Preferred setup on 308/6.5CM large frame?

[cloverleaf22]

How does everyone like their large frames setup (i.e. role/optic/barrel length/profile) and what do you think makes the most sense? Lets say you could have one or two large frames rather than a bunch setup in specific ways.

I tried the lightweight battle rifle type setup with a lpvo a lot of people seem to be doing lately but pretty much came to the conclusion that for anything within the range of 5.56 the weight, cost, recoil, and noise outweigh the positives. I'm now going the 20" medium-heavy barrel route with a 2-10 to take advantage of the range the cartridge offers, that is the biggest benefit over 5.56 after all. It's going to be a pig but even my "lightweight" build was heavy with a mag and optics, so oh well.

 

[Mattrmvpd]

I run a 12.5” (.308). Mounted is a Vortex 1-8 in a QD mount. Its a pig but I prefer the extra knock down power of the .308.

I use it as my 350-ish yard and IN gun.

 

[gac700]

Check out V Seven Weapon Systems

I’m running a suppressed 16” .308 with Halo thermal for hogs. It is a sweet setup.

 

[CaptArab]

I've played with lots of setups. Suppressed 16" with lightish 2-12, 2.5-10, even 3-9 is where it's at IMO.

I'd take a 13.5 with LPVO too but I'm too lazy to SBR and need a legit stock for 308 recoil.

Anything past 16" and I'll take a bolt gun.
That's after running an 18" 308 and 20" 6.5

I also really like the Moe rifle stock.

 

[nn8734]

How does everyone like their large frames setup (i.e. role/optic/barrel length/profile) and what do you think makes the most sense? Lets say you could have one or two large frames rather than a bunch setup in specific ways.

I tried the lightweight battle rifle type setup with a lpvo a lot of people seem to be doing lately but pretty much came to the conclusion that for anything within the range of 5.56 the weight, cost, recoil, and noise outweigh the positives. I'm now going the 20" medium-heavy barrel route with a 2-10 to take advantage of the range the cartridge offers, that is the biggest benefit over 5.56 after all. It's going to be a pig but even my "lightweight" build was heavy with a mag and optics, so oh well.

Here’s mine (Mk11 mod 0), SB 4-16x42. Soft shooting, effective to 900m+.

20” bbl. I also had an ACC (16”) with a mk6 1-6 but reached the same conclusion you did in that the extra weight made the juice not worth the squeeze inside 500m.

 

[erlarson74]

Larue Tactical OBR 308 with Leupold 6.5x20 LR/T. I know the Leupold is not the latest or greatest but it works.

 

[the monk]

Check out V Seven Weapon Systems

I’m running a suppressed 16” .308 with Halo thermal for hogs. It is a sweet setup.Did you get

Did you get the Harbinger or just a V Seven barrel?

 

[gac700]

I purchased the Harbinger 20” 6.5 Creedmoor which is roughly a pound heavier than the .308. I returned my lower to have a .308 upper fitted for hog hunting. I was going for as light of a build as possible.

The 6.5 had an Eotech Vudu 5-25 on it. It was also a nice setup but I haven’t shot it as much as the .308.

V Seven was great to work with. I added adjustable gas blocks to both uppers. I have a .338 Federal barrel that I may send in for a third upper.

Their rifles are light, which you have to handle to appreciate. The .308 is handy locked into a RRS tripod while trudging through plowed fields chasing hogs.

 

[the monk]

I purchased the Harbinger 20” 6.5 Creedmoor which is roughly a pound heavier than the .308. I returned my lower to have a .308 upper fitted for hog hunting. I was going for as light of a build as possible.

The 6.5 had an Eotech Vudu 5-25 on it. It was also a nice setup but I haven’t shot it as much as the .308.

V Seven was great to work with. I added adjustable gas blocks to both uppers. I have a .338 Federal barrel that I may send in for a third upper.

Their rifles are light, which you have to handle to appreciate. The .308 is handy locked into a RRS tripod while trudging through plowed fields chasing hogs.

How are they on accuracy? I have one of his 556 barrels on a Recce I built out and its half moa but always wondered what his 308 / 6.5 barrels would do.

 

[Thorbeast]

I agree with the comments above... Lightweight large frame wasn't worth the effort. Full mag, larger receivers, heavier BCG and optics meant it was going to be heavy relative to an ar15 no matter what. I settled on a 4-16x42 NF, arca rail, supercal bipod and 16" 308 and 20"6.5 creedmoor barrel for a LMT MWS.

 

[GUNNER10]

Personally, I am a fan of shorter 308's with a LPVO. I have 13.5 lmt mws that I really like, and honestly depending on what's hanging on it, it can do carbine stuff if it's stripped down to an RDS.

I also have a 20 inch 6.5 that's a laser with a 3-18 class optic.

 

[tate1976]

I run a wilson combat 6.5 creed with a khales 6/24 it’s a bit heavy but I don’t mind.

 

[r.tenorio671]

How does everyone like their large frames setup (i.e. role/optic/barrel length/profile) and what do you think makes the most sense? Lets say you could have one or two large frames rather than a bunch setup in specific ways.

I tried the lightweight battle rifle type setup with a lpvo a lot of people seem to be doing lately but pretty much came to the conclusion that for anything within the range of 5.56 the weight, cost, recoil, and noise outweigh the positives. I'm now going the 20" medium-heavy barrel route with a 2-10 to take advantage of the range the cartridge offers, that is the biggest benefit over 5.56 after all. It's going to be a pig but even my "lightweight" build was heavy with a mag and optics, so oh well.

....we don't always let "logic" rule our gun decisions

...despite having a 16" .308 and it is fun for me, my 20" 6.5CM upper is better suited for distance beyond a .223/556's and the 16" 308's range capability....as I get more time on the 6ARC, it could possibly supplant the large frame

.... 16" 300BLK and .223Wylde/556 NATO cover a broader range of uses inside of 500M, more so the 223/556 beyond 300M

.... 10" 300BLK is my preferred HD/Urban platform

...in a worst case scenario, I anticipate .223/556 and .308 ammo will be more commonly attainable (6.5CM is getting there, slowly).

....In an absolute ROL failure and chaos, whatever calibers the LE and MIL, or occupying force, are using may be the only source of re-supply

YMMV

 

[BCP]

I had a PWS mk214 with a Leupold M3 scope that I liked a lot. Have had POFs, Larue, DPMS SASS, ones I built etc.

They always get sold because I find 223 more fun to shoot, more economical, you can have just as much fun for a fraction of the cost.

 

[Thorbeast]

I had a PWS mk214 with a Leupold M3 scope that I liked a lot. Have had POFs, Larue, DPMS SASS, ones I built etc.

They always get sold because I find 223 more fun to shoot, more economical, you can have just as much fun for a fraction of the cost.

I think 6arc could replace most of my large frame needs.

 

[Jsp556]

16” MWS with a NF2.5-10 just works

 

[theLBC]

i run a piston driven scar 20s with a 3.6-18x mark 5hd.
i think 10x is a bit on the low side to pick up smaller targets at distances you can reach with 20" .308 on a precision platform.

 

[RUTGERS95]

16” MWS with a NF2.5-10 just works

1-8x here

 

[freedom71]

16" KAC SR-25 .308 APC with a March 4.5-27 and Spuhr mount and an offset Shield SIS with Arisaka offset mount. My older eyes need more magnification, so the March scope functions as a nice 18-20x on the upper end. I chose it because it's lighter and shorter and has a wider FOV.

I'd like to get a 22" KAC 6.5 upper when they become available.

 

[hlee]

If I’m taking the weight penalty of a large frame gasser, it better be better at SOMETHING than a small frame. With that in mind, mine is an 24” bull barreled 308. I only have two regrets. One, the muzzle isn’t threaded. Two, it is 308 and not 6.5 creedmoor.

For hits on steel, I prefer a 6.5 Grendel. The ballistics are a wash, and the smaller rifle is both lighter and softer shooting.

 

[Pappasniper]

I like my big frame gassers, MWS guns, 16CL, 20SS, 6.5CM and Colt CM 6.5. My favorite optic for big gassers is an ATACR 4-16X42, love that optic. I have an ACOG on one gun, fun to play with as well.

PB

 

[Paradox]

How does everyone like their large frames setup (i.e. role/optic/barrel length/profile) and what do you think makes the most sense? Lets say you could have one or two large frames rather than a bunch setup in specific ways.

I tried the lightweight battle rifle type setup with a lpvo a lot of people seem to be doing lately but pretty much came to the conclusion that for anything within the range of 5.56 the weight, cost, recoil, and noise outweigh the positives. I'm now going the 20" medium-heavy barrel route with a 2-10 to take advantage of the range the cartridge offers, that is the biggest benefit over 5.56 after all. It's going to be a pig but even my "lightweight" build was heavy with a mag and optics, so oh well.

308 DPMS, 24" Bull, buts its not for carting around, and weighs almost 17lbs unloaded, but stable, very little recoil and doens't get hot and lose its zero, my 20" PSA is good for 10 rounds then won't even hit paper at 200 yards till it cools for 30min, worthless any long range target use. Only thing worse i've seen is a $6500 AR in 300 Win Mag with a 22" carbon barrel, those are good for 2-3 shots then useless for 15 minutes. If its for running around with and taking a shot or two here and there fine, but for target its a bull or you just toss the gun and throw stones, as youll at least you'll hit something.

If I’m taking the weight penalty of a large frame gasser, it better be better at SOMETHING than a small frame. With that in mind, mine is an 24” bull barreled 308. I only have two regrets. One, the muzzle isn’t threaded. Two, it is 308 and not 6.5 creedmoor.

For hits on steel, I prefer a 6.5 Grendel. The ballistics are a wash, and the smaller rifle is both lighter and softer shooting

I have the same setup, but you don't get much from the 6.5 till your past 5-600 and with factory loads, at 1000 hitting steel its just spending 3x the money with zero benefit, and after 1000 an AR is really at is limits aside from the few 300wm and 338 lapuas, and after watching a carbon barreled 300 this weekend, 100yards was hard. If you have a specific need then the 6.5 is the better choice, but even then why not .260, 7mm-08 etc. if i'm paying a premium for something i'm gonna pay the biggest premium for the buck. here a cool AR for the just because crowd in 338 Lapua lol

Semi Automatic Rifles - SLR Rifles for Sale : Noreen Firearms

The semi automatic rifles for sale at Noreen Firearms. SLR Rifles Used for target practice and hunting for faster follow up shots and bolt action accuracy. Our semi autos are very accurate because of our tight tolerances, craftsmanship, and attention to detail.

onlylongrange.com

 

[RUTGERS95]

16" cut down so that with dead air break it's right at 16" so the shorter barrel 308 with a 1-8x is a perfect set up. I don't need to hit anything past 700yds

 

[Vynz]

I end up building the same rifle over and over again; I obviously have a lack of imagination.

In the AR-10 size the most recent iteration is: SLR B30 receiver with Ion Hybrid 16” Handguard, 18” BSF 6.5 Creedmoor barrel, SLR titanium gas block, Helix 762Ti, HiperFire trigger, Forward Controls Safety, Magpul UBR G2 stock, Magpul K2 grip, JP VMOS BCG and SCS, with a Vortex LHT 4.5-22x50 scope with offset RDS (508T with backordered ACRO P2).

I simultaneously built my wife invented an excuse to build an AR-15 size rifle with ADM UIC lower, Aero Enhanced Upper with 12” Handguard, 16” BSF 6ARC barrel, SLR Titanium gas block, Q Half-Nelson, HiperFire trigger, Forward Controls Safety, Vltor EMOD stock, K2 grip, JP LMOS BCG and SCS, with a Vortex Razor G3 1-10x24.

Now that both builds are done I keep looking at my “wife’s rifle” wondering why I didn’t just build two of those. The majority of shooting I enjoy with a semi-auto is covered by the 6ARC build in a lighter, more handy package. The part the 6ARC build can’t do - is covered by rifles I have setup specifically for longer range shooting which performs way better than my SLR build. Currently I’m thinking I may just change the SLR build into an 8.6 Blackout build by purchasing a 12.5” Faxon 8.6 barrel, SLR 8 - 11” handguard, and a 338 silencer to save face.

 

[Naaman]

Interesting thread. I've been looking at a large frame in the medium term and been trying to figure out whether weight savings is more or less important than performance.

Some good info in this thread.

 

[acudaowner]

right now it's a mtu 26'' barrel all the mdt weights inside and out + 2 , 7lb steel bars one on each side weight with the extra weights is 44lbs in total and I wanted to get a thicker barrel ( non tapered ) and longer 28''+ 2'' break not sure how much extra it would add but i am sure It will be fun .

 

[Paradox]

Interesting thread. I've been looking at a large frame in the medium term and been trying to figure out whether weight savings is more or less important than performance.

Some good info in this thread.

To me the sole purpose of the 308 platform 1000 yard shots prone with a bipod, with 24" plus heavy target barrels, for running around there's plenty of capable AR15 calibers and with 224 Valkyrie you can reach 1200. all depends on purpose, for the house a short 300AAC, for small frame target an 18" match 5.56, etc. and as for the dime a dozen 16" M4 appearing majority, you just buy it to say you have one, because its not much good for anything else except maybe a throwaway so if you actually use it, you won't have to worry about law enforcement destroying it from collecting dust in an evidence lockup

 

[Naaman]

To me the sole purpose of the 308 platform 1000 yard shots prone with a bipod, with 24" plus heavy target barrels, for running around there's plenty of capable AR15 calibers and with 224 Valkyrie you can reach 1200. all depends on purpose, for the house a short 300AAC, for small frame target an 18" match 5.56, etc. and as for the dime a dozen 16" M4 appearing majority, you just buy it to say you have one, because its not much good for anything else except maybe a throwaway so if you actually use it, you won't have to worry about law enforcement destroying it from collecting dust in an evidence lockup

My only .308 is a Model 70. But my shooting isn't at a level where the additional reach makes a difference... for now.

My perception is that, for the same money, a bolt gun is "more accurate" at a given distance than a semi (but that AR10s are more accurate than other semis).

I suppose that if I were going to only shoot prone at long distance, it wouldn't much matter which platform I had in 99% of situations, but that hits would be more likely with a bolt gun, while obviously slower and less capacity.

I read an article by Jack Carr talking about how much of a game changer the SASS and MK12 were (he lumped them together, as a departure from the traditional bolt actions). The kinds of things he and others have said about the large frames in the DMR/sniper role got me thinking about what a large frame is and what it isn't (but I haven't reached a definite conclusion on that issue yet ).

Maybe I'll just slap irons on it and start from there before trying to "set it up" a certain way.

 

[Paradox]

A good bolt will always out do an autoloader as it was just too many moving parts and play in an AR platform they have however come along way since the old days hitting 1000 yards with one is relatively easy but even in the military the M1 10 as it’s called wasn’t light because they jammed and even at say 900 or 1000 yards still a world away from with the 300 win mag and 338 Lappula we’re capable of , And as for the Mark 12 I built a replica of one and that’s actually a functional A.R. 15 it has an 18 inch mash barrel full rifle stock and with the proper am home there’s a 5 to 600 yard gun, the ones I hate however are the diamond dozen M4 look-alikes basically the M4 itself is a crappy gun and the government only pays around 650 bucks for them then you take away that selector switch few lighter parts in a 16 inch barrel and you have the worth of civilian model, most people don’t realize that the reason there’s so many crazy A.R. 15 calibers is that the original M 16 was a 20 inch gun designed fire specific ammunition and length wasn’t a concern, to me unless you’re in a building trying to clear it a couple inches shouldn’t make a difference either thing is the M4 once he started chopping the barrel down wiped out the velocity this was just like I was telling someone earlier who built his building and 11 1/2 inch 308 is completely useless he was so much velocity and there’s so much bullet drop even if you can manage a 3 to 500 yard shot the bullet is traveling so slowly that it hits with less than 200 foot pounds of energy which is zero literally in the short range the big 308 has half the energy of a 75 grain 223.
Personally in my opinion nearly any gun on the market is better than they are eject the M1 a for instance is a very finally manufactured weapon and then just take a look at an accuracy international ball gun you can get a nice 308 version for under 5000 or less than half of what the silly M110 goes for

 

[Jsp556]

I’d like to try a 14.5” 6.5Creedmoor in a MWS if they’ll gas them can friendly. Hopefully they will offer them in both stainless and chrome lined.

 

[Rudy Gonsior]

A good bolt will always out do an autoloader as it was just too many moving parts and play in an AR platform they have however come along way since the old days hitting 1000 yards with one is relatively easy but even in the military the M1 10 as it’s called wasn’t light because they jammed and even at say 900 or 1000 yards still a world away from with the 300 win mag and 338 Lappula we’re capable of , And as for the Mark 12 I built a replica of one and that’s actually a functional A.R. 15 it has an 18 inch mash barrel full rifle stock and with the proper am home there’s a 5 to 600 yard gun, the ones I hate however are the diamond dozen M4 look-alikes basically the M4 itself is a crappy gun and the government only pays around 650 bucks for them then you take away that selector switch few lighter parts in a 16 inch barrel and you have the worth of civilian model, most people don’t realize that the reason there’s so many crazy A.R. 15 calibers is that the original M 16 was a 20 inch gun designed fire specific ammunition and length wasn’t a concern, to me unless you’re in a building trying to clear it a couple inches shouldn’t make a difference either thing is the M4 once he started chopping the barrel down wiped out the velocity this was just like I was telling someone earlier who built his building and 11 1/2 inch 308 is completely useless he was so much velocity and there’s so much bullet drop even if you can manage a 3 to 500 yard shot the bullet is traveling so slowly that it hits with less than 200 foot pounds of energy which is zero literally in the short range the big 308 has half the energy of a 75 grain 223.
Personally in my opinion nearly any gun on the market is better than they are eject the M1 a for instance is a very finally manufactured weapon and then just take a look at an accuracy international ball gun you can get a nice 308 version for under 5000 or less than half of what the silly M110 goes for

Ummm…

A 168 SMK lobbed out at 2200ish still has almost 700ft. lbs at 500y, While a 77 SMK smoking at 2750ish is only 500 or so ft. lbs. at the 500y mark You’d have to start that .308 at subsonic velocity to even start dabbling down into 200ft. lbs.

I am not saying a 11.5” .308 is in any way optimal or an efficient use of the cartridge but your fuddy math doesn’t line up with the actual science. The projectiles efficiency (BC) has a significant impact on how much energy is carried down range.

 

[KYAggie]

There are ways to build large platforms very light if you are so inclined. Here’s a link to a 20” barreled 6.5 I built that weighs 6.5# without mags and optics.

Lightweight 2A Arms Xanthos 6.5 CM Build

First, I want to say this is ALL Breastroker’s fault on M14forum. I had not given the AR10 platform the slightest look of interest because they are as heavy as the M14/M1A and they are not standardized as far as parts go; why bother was how I saw it, so I continued playing with the M14/M1A...

www.snipershide.com

Here’s a picture of a 16” Faxon gunner barreled 308 I built that weighs 6# before optics and mags. Very similar weight to a 5.56.

 

[Paradox]

Ummm…

A 168 SMK lobbed out at 2200ish still has almost 700ft. lbs at 500y, While a 77 SMK smoking at 2750ish is only 500 or so ft. lbs. at the 500y mark You’d have to start that .308 at subsonic velocity to even start dabbling down into 200ft. lbs.

I am not saying a 11.5” .308 is in any way optimal or an efficient use of the cartridge but your fuddy math doesn’t line up with the actual science. The projectiles efficiency (BC) has a significant impact on how much energy is carried down range.

I used a balistics computer for the math, and my own 168s clocked at 2640, that said most 308 specs are based on a 24" Barrel, so cutting it donwn to 11.5 you're losing big, at 500 yards the 24" hits with1055 ft lbs, and he same round in the 11.5 is down to 170 ft lbs and 676fps, not to mention the 300" of drop, vs 65" on the 24" thing is all you get is a noisy, heavier weapon that does't do anything well, AR10s, LR308s are for target or mid range sniper duty, to each his own, but the SR lower is the Ferarri and the 11.5" barrel is the set of k-mart tires you plan on using at the 24 hours of daytona, and for home use all this stuff sits in the safe and i keep an 870 Rem nearby and carry a combat commander in 38 super with very hot ammo, its cool to build odd ball stuff but using any intermediate caliber in short barrels just kills velocity very quickly, and thats why they developed the 300AAC, purpose built for short barrels and probably the quietest suppressed rifle caliber out there. so i've got that with 7.5 inch and my 11.5" 5.56 needs 75 grain for decent effectiveness, and only reason even have it was because i had enough parts to put it together, otherwise the 300 would win. oh and most online computers don't offer a field to change barrel length and without the ability to edit that field you can't get good numbers.

 

[Paradox]

There are ways to build large platforms very light if you are so inclined. Here’s a link to a 20” barreled 6.5 I built that weighs 6.5# without mags and optics.

Lightweight 2A Arms Xanthos 6.5 CM Build

First, I want to say this is ALL Breastroker’s fault on M14forum. I had not given the AR10 platform the slightest look of interest because they are as heavy as the M14/M1A and they are not standardized as far as parts go; why bother was how I saw it, so I continued playing with the M14/M1A...

www.snipershide.com

Here’s a picture of a 16” Faxon gunner barreled 308 I built that weighs 6# before optics and mags. Very similar weight to a 5.56.

Problem is light barrels are only good if you don't plan on using them for target work, because the minute they get hot a 300 yard shot is a challenge, my 20" 308 is good for 10 rounds last round can be 850 yards, and can't even hit paper at 300, cool it and it shoots again. Just curious what the draw is towards short barreled ARs in calibers meant for range?

 

[Ledzep]

I've tried large frame AR's from 6.5 to .308, 8lb to 18lb, 16" to 26", and each time I ended up with a rifle that sat in the safe.

AR-15's handle the 0-600 space with less weight and better reliability. Bolt actions handle the 300-1200yd space with equal/less weight and better precision. YMMV.

 

[Paradox]

I've tried large frame AR's from 6.5 to .308, 8lb to 18lb, 16" to 26", and each time I ended up with a rifle that sat in the safe.

AR-15's handle the 0-600 space with less weight and better reliability. Bolt actions handle the 300-1200yd space with equal/less weight and better precision. YMMV.

I treat mine like any precision rifle, table top with a bipod and shoot to a 1000, its stable, with very little recoil and a solid sub minute performance. I have a MK12 kinda clone, with an 18" match barrel, but 600 is pretty much it. I did however just throw a 20" 224 Valkyrie together which would be both worlds, its light and if it really does 1200 yards on factory match, its got my 308 beat target wise, so curious how that will turn out, plus it was so cheap it was like stealing. $125 PSA lower and the 224 upper was a blem in the finish i still haven't found, but landed that for $240, so prob my cheapest build to date.

 

[Rudy Gonsior]

I used a balistics computer for the math, and my own 168s clocked at 2640, that said most 308 specs are based on a 24" Barrel, so cutting it donwn to 11.5 you're losing big, at 500 yards the 24" hits with1055 ft lbs, and he same round in the 11.5 is down to 170 ft lbs and 676fps, not to mention the 300" of drop, vs 65" on the 24" thing is all you get is a noisy, heavier weapon that does't do anything well, AR10s, LR308s are for target or mid range sniper duty, to each his own, but the SR lower is the Ferarri and the 11.5" barrel is the set of k-mart tires you plan on using at the 24 hours of daytona, and for home use all this stuff sits in the safe and i keep an 870 Rem nearby and carry a combat commander in 38 super with very hot ammo, its cool to build odd ball stuff but using any intermediate caliber in short barrels just kills velocity very quickly, and thats why they developed the 300AAC, purpose built for short barrels and probably the quietest suppressed rifle caliber out there. so i've got that with 7.5 inch and my 11.5" 5.56 needs 75 grain for decent effectiveness, and only reason even have it was because i had enough parts to put it together, otherwise the 300 would win. oh and most online computers don't offer a field to change barrel length and without the ability to edit that field you can't get good numbers.

Bro, what you’re saying does not entirely make sense in regards ballistic data. Ballistic solvers don’t offer a field for barrel length because they utilize the rifles estimated muzzle velocity for calculating solutions.

I ran a Mk17 (13” 7.62x51mm) for the better part of a ten month deployment. The specific configuration of that platform was for a suppressed, compact-lightweight SASS, with decent barrier performance, effective from 0-600m which it did well.

More importantly real world MV data that I collected from AB39 (175 grain FGMM) delivered just a smidge over 2300fps. Anyone with an actual 11.5 can chime in but I’ll ball park and say a 168 SMK at 2200fps is totally achievable but let’s get crazy and say we have a MV of 2100fps with a 168 SMK…

Now I am not sure what ballistic solver you running but JBM is pretty not bad at pumping out accurate results with the parameters we’re discussing. I’d highly recommend you double check your inputs. Because frankly speaking you are wrong by a fair margin.

Now again when you compare the slow moving .308 against the zippy little .223, you can see the performance is agreeably superior in regard to most categories WITH THE EXCEPTION of energy.

There’s as saying “no replacement for displacement” I think that applies well in regards to this.

I think SBR in .308 are niche as fuck but if that niche is extra energy in a small package then it’s a viable option.

 

[hlee]

The above, not to mention that drop at distance can be accounted for- if you have a good range estimation. And, the wind correction is a wash between the two estimates above. Ebbiv has been a pretty prolific poster since his arrival last month. But, I would suggest more reading and less posting, as much of what he has posted is... flawed...

 

[Paradox]

Bro, what you’re saying does not entirely make sense in regards ballistic data. Ballistic solvers don’t offer a field for barrel length because they utilize the rifles estimated muzzle velocity for calculating solutions.

I ran a Mk17 (13” 7.62x51mm) for the better part of a ten month deployment. The specific configuration of that platform was for a suppressed, compact-lightweight SASS, with decent barrier performance, effective from 0-600m which it did well.

More importantly real world MV data that I collected from AB39 (175 grain FGMM) delivered just a smidge over 2300fps. Anyone with an actual 11.5 can chime in but I’ll ball park and say a 168 SMK at 2200fps is totally achievable but let’s get crazy and say we have a MV of 2100fps with a 168 SMK…View attachment 7861934
Now I am not sure what ballistic solver you running but JBM is pretty not bad at pumping out accurate results with the parameters we’re discussing. I’d highly recommend you double check your inputs. Because frankly speaking you are wrong by a fair margin.

Now again when you compare the slow moving .308 against the zippy little .223, you can see the performance is agreeably superior in regard to most categories WITH THE EXCEPTION of energy.

There’s as saying “no replacement for displacement” I think that applies well in regards to this.
View attachment 7861933
I think SBR in .308 are niche as fuck but if that niche is extra energy in a small package then it’s a viable option.

I get what you're saying but heres where i think we're drifting apart, take the first bullet company data will print velocities based on a 24" barrel, so populate the database specs for the round and get your calculation, or you clock the bullet real time and use an average of 3 or 4 samples.

Now for the shorter barrel you either need a calculator with the formula available or you clock that bullet realtime and get your average, plug those numbers in and now you have your spread. So what am I missing? the only other way is if you can find online data for that exact bullet and barrel. I used real data from real testing of my own rifle and ammo in formula. so for me i had to use a formula with length becauase there was no short barrel for me to test, so if im still wrong please explain

 

[Bigjake83]

I've found the sweet spot for most rifles is a 20" Barrel.

 

[Rudy Gonsior]

I get what you're saying but heres where i think we're drifting apart, take the first bullet company data will print velocities based on a 24" barrel, so populate the database specs for the round and get your calculation, or you clock the bullet real time and use an average of 3 or 4 samples.

Now for the shorter barrel you either need a calculator with the formula available or you clock that bullet realtime and get your average, plug those numbers in and now you have your spread. So what am I missing? the only other way is if you can find online data for that exact bullet and barrel. I used real data from real testing of my own rifle and ammo in formula. so for me i had to use a formula with length becauase there was no short barrel for me to test, so if im still wrong please explain

You’re missing sooooooo much.

I see you seem to be using the Norma Ballistic App…which honestly looks like garbage. I downloaded it to get a look at what you’re look at and all I can say is I am embarrassed for Norma. There’s some serious fucker with it.

I’d highly recommend something like BallisticArc (it’s free) as it’s super easy to work with and has a good library. But pretty much most reputable ballistic solvers are the same in that they use point of mass based algorithms to provide solutions.

Sure they all got their own user interfaces and some have better libraries but at their core there’s not much of a difference especially inside transonic flight.

Key points of input into any solver is the current atmospherics which define density of the medium (the air) which your projectile is traveling through. That’s fairly Cut and dry.

- Station pressure
- Ambient air temperature
- Relative humidity

Secondly is rifle/projectile profile. You’ll have all the little things like, zero range twist rates, hight over bore, etc. but the BIG ticket inputs are:

- Muzzle Velocity
- Ballistic Coefficients

The fact that the Norma App doesn’t have a Muzzle Velocity input is HUGH RED FLAG.

It has “barrel length” but that’s not at all helpful because barrels with the same chambering, shooting the same projectiles and of the same length …can produce two total different velocities, sometimes with 100 FPS differences.

There’s several ways of estimating MV but barrel length only puts you in a really rough ball park. Optical chronographs usually I’m not terribly reliable either unless calibrated to the variations in light conditions. A lab radar or magneto speed will get you +/- 1% of your actual MV and truing drops complete that last bit.

The numbers for my 13” MK17 are real world collections from truing and only an 1.5 “ of difference from your theoretical short-barreled 308.

Bottom line is your calculations via Norma’s app and general miss understanding of ballistics has led you astray. Don’t take it personal I just what to get this information back into correct context and the information presented was simply not factual.

 

[KYAggie]

Problem is light barrels are only good if you don't plan on using them for target work, because the minute they get hot a 300 yard shot is a challenge, my 20" 308 is good for 10 rounds last round can be 850 yards, and can't even hit paper at 300, cool it and it shoots again. Just curious what the draw is towards short barreled ARs in calibers meant for range?

As to your first sentence regarding short barrels; that 6.5 I built has a 20“ Faxon heavyweight fluted 5r match barrel. It’s not a lightweight barrel and the gun still weighs 6.5#. The 308 has a 16” Faxon gunner weight, which again is not exactly a lightweight barrel; I could have gone with their pencil weight to shed even more weight. I wanted a 18” fluted, but I came upon a really great deal on the 16 and since that Faxon gunner weight is still a good suppressor host I bought it. As far as how accurate they are when they get hot, I’ll have to do more testing. I haven’t shot the 6.5 hot enough to loose accuracy. The 308 has only been to the range once and I need to do further playing around with it, but here are a couple targets from that day:

The first one was shot with 168 Federal Match. I have the area 419 Hellfire brake on it and my can has been modified by Ecco machine to fit that mount. I was testing the POI shift between the can and brake. The group circled was going back and forth between the can and the brake adjusting the scope 1.3 MRAD between shots. Looks promising and repeatable to me. The second group was shot with 1982 Malaysian surplus ammo. I’ve never had surplus shoot that well. Both of these groups were shot with a 1-6 SWFA SS scope; I wonder what it would do with a higher power scope at range and I’ll find out someday.

I like the short barrel large frames because they can be built as light and fast as a small frame, pack a considerable additional amount of energy, and I’ve found are plenty accurate for the 600 yard range I have access to. I don’t plan to run 168’s out of the 16” 308 though. I have Nosler 125 BT’s, 140 and 155 CC’s, and Sierra 125 Match I’ll try in it. Those weights across 600 yards should do very well.

 

[Paradox]

You’re missing sooooooo much.

I see you seem to be using the Norma Ballistic App…which honestly looks like garbage. I downloaded it to get a look at what you’re look at and all I can say is I am embarrassed for Norma. There’s some serious fucker with it.

I’d highly recommend something like BallisticArc (it’s free) as it’s super easy to work with and has a good library. But pretty much most reputable ballistic solvers are the same in that they use point of mass based algorithms to provide solutions.

Sure they all got their own user interfaces and some have better libraries but at their core there’s not much of a difference especially inside transonic flight.

Key points of input into any solver is the current atmospherics which define density of the medium (the air) which your projectile is traveling through. That’s fairly Cut and dry.

- Station pressure
- Ambient air temperature
- Relative humidity

Secondly is rifle/projectile profile. You’ll have all the little things like, zero range twist rates, hight over bore, etc. but the BIG ticket inputs are:

- Muzzle Velocity
- Ballistic Coefficients

The fact that the Norma App doesn’t have a Muzzle Velocity input is HUGH RED FLAG.

It has “barrel length” but that’s not at all helpful because barrels with the same chambering, shooting the same projectiles and of the same length …can produce two total different velocities, sometimes with 100 FPS differences.

There’s several ways of estimating MV but barrel length only puts you in a really rough ball park. Optical chronographs usually I’m not terribly reliable either unless calibrated to the variations in light conditions. A lab radar or magneto speed will get you +/- 1% of your actual MV and truing drops complete that last bit.

The numbers for my 13” MK17 are real world collections from truing and only an 1.5 “ of difference from your theoretical short-barreled 308.

Bottom line is your calculations via Norma’s app and general miss understanding of ballistics has led you astray. Don’t take it personal I just what to get this information back into correct context and the information presented was simply not factual.

I use strelok, the norma app was soley because it had the length input, and i used their match ammo, and i could get 20 different number depending on the bullet itself, obviously M80 crap will be far worse than 168 or 175 match, i have a wide range of AR15 lengths so next time out i'll clock them all and have real numbers, and true up my dopes with live data, and it was a labradar borrowed from a local Sheriffs Dept and operated by one of their veteran snipers, and my scope hights are measured, as for temp, pressure and humidity, under a 1000 its gotta be pretty wide spread to make much difference., if you wanna talk flying and altimeter settings on the other hand, that might very well kill you if your off. anyway, pretty much all my data been verified, and my dopes at that range are as perfect as you'd get. like i said I attempted the norma simply for the extra field. that link you sent shows massive losses in velocity with the base surplus crap,

Heres what i'm missing, I have accurate data from 100 on up to 1000, drop, velocity and energy along with the corresponding dopes that got the shot done, and out of a 1.10 twist 24" barrel with 175gr Norma GTX , now without another upper handy, where am i supposed to get data for this round on this day, with these conditions without live testing? I just want to know where the data data is comming from to create another chart with all he numbers tied to the shorter barrel. and if that makes me stupid so be it, but i'd like to know

 

[theLBC]

i'd go with a 20" heavy profile on a piston driven gun and decent optic that isn't a boat anchor.
while not ideal for carrying around, it is at least doable, without sacrificing that much in effective range (at that point, a bolt gun would be better).
something like a scar 20s that can shoot all day.

 

[rlsmith1]

16” 308 for me with a Sandman S on the end and a MK5 3.6-18 on top. It’s a great setup and I’ve got offset irons but don’t think they are really necessary. No light or laser at this point because the only use it gets at night is with a PVS30. I should probably have a white light on there though.

I also have an 18” 6.5 Creed upper with a criterion barrel that absolutely hammers. Not crazy speed but if I’m shooting consistently past 1,200 I’ll grab a bigger bolt gun.

I do notice the longer barrel of the Creed and have thought about chopping the 16” back and pinning to 16” but I shoot it unsuppressed enough I wouldn’t really like that. Both are braked as opposed to my 556’s that are almost exclusively FH.

My goal was to have a 308 I can shoot cheap (while honing fundamentals) and a 6.5 for when I want to be more precise at distance. I have no need to shoot an AR of any type past 1,000 but the Creed could do it if needed. Long range is Norma and Lapua range

 

[Paradox]

As to your first sentence regarding short barrels; that 6.5 I built has a 20“ Faxon heavyweight fluted 5r match barrel. It’s not a lightweight barrel and the gun still weighs 6.5#. The 308 has a 16” Faxon gunner weight, which again is not exactly a lightweight barrel; I could have gone with their pencil weight to shed even more weight. I wanted a 18” fluted, but I came upon a really great deal on the 16 and since that Faxon gunner weight is still a good suppressor host I bought it. As far as how accurate they are when they get hot, I’ll have to do more testing. I haven’t shot the 6.5 hot enough to loose accuracy. The 308 has only been to the range once and I need to do further playing around with it, but here are a couple targets from that day:

The first one was shot with 168 Federal Match. I have the area 419 Hellfire brake on it and my can has been modified by Ecco machine to fit that mount. I was testing the POI shift between the can and brake. The group circled was going back and forth between the can and the brake adjusting the scope 1.3 MRAD between shots. Looks promising and repeatable to me. The second group was shot with 1982 Malaysian surplus ammo. I’ve never had surplus shoot that well. Both of these groups were shot with a 1-6 SWFA SS scope; I wonder what it would do with a higher power scope at range and I’ll find out someday.

I like the short barrel large frames because they can be built as light and fast as a small frame, pack a considerable additional amount of energy, and I’ve found are plenty accurate for the 600 yard range I have access to. I don’t plan to run 168’s out of the 16” 308 though. I have Nosler 125 BT’s, 140 and 155 CC’s, and Sierra 125 Match I’ll try in it. Those weights across 600 yards should do very well.

It was interesting, just shoot a bunch out to max distance then go back to a hundred and see if your grouping changes, or misses the paper completely, it was only my gun the first time so thought maybe just too light or something, but then watching a 2 guys with carbon barrels completely go to hell was bizarre, Watch a 300 win mag make couple 5-600 yard shots, then scratch there head as they miss the next try, so then take a shot at a hundred and land the round a good 4 inches off the paper, i didn't even think that was possible

 

[Paradox]

16” 308 for me with a Sandman S on the end and a MK5 3.6-18 on top. It’s a great setup and I’ve got offset irons but don’t think they are really necessary. No light or laser at this point because the only use it gets at night is with a PVS30. I should probably have a white light on there though.

I also have an 18” 6.5 Creed upper with a criterion barrel that absolutely hammers. Not crazy speed but if I’m shooting consistently past 1,200 I’ll grab a bigger bolt gun.

I do notice the longer barrel of the Creed and have thought about chopping the 16” back and pinning to 16” but I shoot it unsuppressed enough I wouldn’t really like that. Both are braked as opposed to my 556’s that are almost exclusively FH.

My goal was to have a 308 I can shoot cheap (while honing fundamentals) and a 6.5 for when I want to be more precise at distance. I have no need to shoot an AR of any type past 1,000 but the Creed could do it if needed. Long range is Norma and Lapua range

Unless you're hand loading a thousand is about all you need and can be done at 50cents a shot. that's always been my issue with the Creedmoor, guys are getting them and never shooting past 4-500 yards for 3x the price of a 308 and and barrel that's shot to shit in a quarter the time. the Creedmoor's advantage over the 308 isn't fully realized till your at the 600 plus mark

6.5 Creedmoor Ballistics Chart - 1000 yards

6.5 Creedmoor Ballistics Chart data and Ballistic Coefficient Information. Muzzle Velocity and Bullet Drop at various ranges. 1000 yards to see how well the High Ballistic Coefficient performs for long range shooting! See how the 6.5 CM compares to the Classic 308

www.mcarbo.com

 

[Rudy Gonsior]

I use strelok, the norma app was soley because it had the length input, and i used their match ammo, and i could get 20 different number depending on the bullet itself, obviously M80 crap will be far worse than 168 or 175 match, i have a wide range of AR15 lengths so next time out i'll clock them all and have real numbers, and true up my dopes with live data, and it was a labradar borrowed from a local Sheriffs Dept and operated by one of their veteran snipers, and my scope hights are measured, as for temp, pressure and humidity, under a 1000 its gotta be pretty wide spread to make much difference., if you wanna talk flying and altimeter settings on the other hand, that might very well kill you if your off. anyway, pretty much all my data been verified, and my dopes at that range are as perfect as you'd get. like i said I attempted the norma simply for the extra field. that link you sent shows massive losses in velocity with the base surplus crap,

Heres what i'm missing, I have accurate data from 100 on up to 1000, drop, velocity and energy along with the corresponding dopes that got the shot done, and out of a 1.10 twist 24" barrel with 175gr Norma GTX , now without another upper handy, where am i supposed to get data for this round on this day, with these conditions without live testing? I just want to know where the data data is comming from to create another chart with all he numbers tied to the shorter barrel. and if that makes me stupid so be it, but i'd like to know

And here’s M80 FMJ at 2200fps, still well over 500ft. lbs. in standard atmospheric conditions…

Look man, this shit isn’t hard and frankly you’d be better off talking less and listen a bit more. I’ve bounced around various threads and the trend I am seeing is you post a lot of opinions, while repeatedly demonstrate that you lack understanding of basic concepts.

Again I don’t want to be a Dick but you’re flat out wrong with the information you’re presenting to others and whether it’s a honest mistake or flat out trolling, I’ll call you on it.

Short barrel .308’s while suffering greatly from ballistic handicap, STILL out perform .223’s in the energy department even with M80 ball.

 

[Naaman]

Skimming the most recent posts, I'm glad to see the thread isn't a back and forth of "dude, you don't know sh!t/I've been there done that since before you were born" etc, etc.

 

[Paradox]

The above, not to mention that drop at distance can be accounted for- if you have a good range estimation. And, the wind correction is a wash between the two estimates above. Ebbiv has been a pretty prolific poster since his arrival last month. But, I would suggest more reading and less posting, as much of what he has posted is... flawed...

Which is the flawed post this time? and i read a lot, and i ask a lot of questions, nobody know everything and nobody can do everything well, but anyone can be their own best and exceptional at anything they set out to do, here's an example, i needed both knees replaced, and roughly 30% are worse off then before, crippled up, in pain, and so on. reason? the didn't post their asses off asking questions. and those that did got the shit comments people on here like. I posted, researched, i even called the manufacturer to spec the knees i needed and then told the doctor what he was going to do, so like you know all this stuff i have the same in my realm so have surgery and components come loose cripple me and require a do over, most can't handle one let alone four, so respect the new set with cement and stabilizing spike, discuss post op recovery and told probably limited from the trauma, and pain, tell him hes wrong, then spend half hour discussing drugs and dosages i want if he wants to do the surgery and off we go. wake up go home do my own therapy because i know that better too, 7 weeks later i go from crippled to one of less than 800 patients to not only recover, but recover with range of real knee in and fully heal in 5 months while the rest suffer for a year and end up with legs that bend 80 degrees to my 153. Its because i spent endless hours of study, i can do drug dose calculations in my head, I'm where I'm at now because it was required. this is no different , its just knew and i'll master it as needed and in the end at worst be consistent. and it might take longer, because when someone reads what you consider rants on knee forums, the ask me a million questions so they can be their best, and i'm happy to help them get to the goal, so they can be their best. when you're really good at something the cost of that experience is sharing it with others. and nobody thats truly ever god at something ever uses it to belittle like this fucking place. So just like the knees, i'm master this with or without help and then thank myself and hopefully outshoot some of the mouths on here.