6x45mm vs 6.5 Grendel

[shooter3225]

Hey guys I've been undecided on which to build and read a bit of the pros/con's of each. I have a couple lowers and was looking into a long range build for the range. Will be shooting steel/paper out to 600-700 yards max. If I already had a rifle length AR I would choose the 6x45, but I'm going to be buying a whole new upper/barrel/bolt etc anyways. Yes I have a lot of 223 brass and my pmags will work but that's not a HUGE concern with me. I wouldn't mind starting a new caliber I just want you guys' opinion if its worth it?? Ballistically is it that much superior? Don't the 6mm bullets have a better BC?

Those of you that have both or have used both, your opinion is most definitely appreciated!!

Thanks

 

[DirtyDave]

The 6x45 is simple and great if you want to shoot something a bit heavier than a 223. Mine shoots the 75gr V-max's very well. Have not tried heavier, but have no need as this gun is for coyotes. You can load the heavier 6mm bullets in a 6x45, but they eat up a lot of case capacity. Mine is a compressed load with 75gr bullets. Probably anything heavier than 85-87gr bullets will limit your powder capacity enough to be a diminishing return. There are lots of guys that load 100gr soft points for hogs, but they are shooting short range.

There are lots of other options if you like 6mm bullets in an AR.
6mmAR, 6x6.8, 6 Grendel, 243 WSSM, to name a few.

 

[thespecialist]

If you're building a new upper anyways, I'd go with the 6x6.8 over either the Grendel or the 6x45. The 6x45 can push 87gr Bergers over 2900fps, but they are singe load only. I was able to push 87gr Hornady BTHP's around 2900 with 8208XBR from a 24" barrel in LC brass, loaded to 2.34" IIRC. I trimmed a notch in the front of some 10 round mags to allow the longer OAL, but it cut the capacity to 5 rounds. The load was mild, but I was out of room for more powder.

The Grendel just made me want to push 6.5's faster, which caused me to build a 260. Couple that with expensive brass and I sent that upper on down the road.

Between 6x45 or 6.5 Grendel though, I'd take the x45 purely because of brass cost. I am a bit of a tightwad though

 

[Scottmilk9]

6.5 grendel hands down, better ballistics than the 6x45 and the 6x6.8. i have made all three and keep going back to my grendel for my go to gun and have hit targets past 1000yds with it.

 

[shooter3225]

Okay I haven't really looked into the 6x6.8 but I have a .308 bolt rifle that I use right now for matches. I'm gonna be building a .260 bolt rifle next but I have some extra lowers and wanted to build a long range 20" AR. Instead of .556 I was thinking maybe 6x45 and pushing something 90-100gr which I've been seeing people have mv around 2600-2700+ which was intriguing. But now thinking about the Gendel it might be nice pushing something heavier since I am going to be building a whole new upper.

If the ballistics were much better I would go Grendel but isn't the BC better on the 6mm rounds

 

[bustin]

Okay I haven't really looked into the 6x6.8 but I have a .308 bolt rifle that I use right now for matches. I'm gonna be building a .260 bolt rifle next but I have some extra lowers and wanted to build a long range 20" AR. Instead of .556 I was thinking maybe 6x45 and pushing something 90-100gr which I've been seeing people have mv around 2600-2700+ which was intriguing. But now thinking about the Gendel it might be nice pushing something heavier since I am going to be building a whole new upper.

If the ballistics were much better I would go Grendel but isn't the BC better on the 6mm rounds

The BCs on the 6mms are better for the weight. A 6mm with the same case capacity as a 6.5 will beat the 6.5. A 6mmAR or 6mm Hagar, 6mmWOA with 95s or 105s would be a very good long range choice.

 

[Scottmilk9]

The problem with the 6mm rounds(i personally own a 6woa and a 6x45), is using the heavier bullets like the 105's, you won't be able to mag feed them and still push them at a velocity that will beat the grendel. The 123gr Amax with a bc of .510. With the 20" barrel and IMR 8208 i can shoot to 1000 before it goes subsonic. Don't get me wrong the 6-6.8(6woa) and the 6x45 have their place, but its not in the long range performance category.

 

[Drifter™]

...looking into a long range build for the range. Will be shooting steel/paper out to 600-700 yards max. ...I have a lot of 223 brass...

... wanted to build a long range 20" AR.

For paper and steel at stated distances, I suggest sticking with the 223 (unless you really want to dabble with another cartridge).

If you haven't already tried it, 223 performance (with appropriate bullets) might surprise you at those distances.

 

[Armored Transport]

If you want rounds that will hammer that you don't have to load yourself look at the Grendel. I took a 264LBC 20" barrel with a Rainier arms ultramatch upper and with A.A. factory Lapua with 123 Scenars holds 1/3moa all day. The ammo for how it's made is a great deal and if you reload the Lapua brass will pay for itself in the long run.....

 

[shooter3225]

For paper and steel at stated distances, I suggest sticking with the 223 (unless you really want to dabble with another cartridge).

If you haven't already tried it, 223 performance (with appropriate bullets) might surprise you at those distances.

Yea my buddy has a .223 bolt rifle that he can hit out even further than that. It was impressive but I think getting away from the 223 is kind of my goal here to some extent. I like the idea of pushing something heavier and I def can use this for some yotes or other varmints out in the desert even tho that wont be the primary use.

I will be loading these myself so that wont make a difference but looking into the other 6mm options it seems if Im understanding this correctly, because of mag issues and powder capacity it might not be the best option to try and push a 90-100gr through the 6x45. If I want to go that heavy or even heavier seems like the Grendel is the better option I just dont know if thats necessary. Seeing how I need a whole upper anyway I was considering though. Most of what Ive read is the best success with the 6x45 is staying with 75s or 87s

 

[LRRPF52]

Will be shooting steel/paper out to 600-700 yards max.

That's where I just start to have fun registering my 16" Grendel carbine. With a 20" rifle chambered in Grendel, you typically will get ~100fps more velocity than a 16", which isn't a huge deal for drop and drift.

To beat the 123gr 6.5mm pills, you need to use the longer VLD-type 6mm pills, and Berger reduced the 6mm 105gr VLD Target bullets from .532 G1 to .493 for BC, with the G7 now at .251 due to the punch out rod.

The 6mm 105gr Hornady A-MAX has a .500 BC, while the 105gr has a .530 BC.

You can get them faster than the 123gr in the Grendel, but for your purposes at 600-700yds, especially if you live in the desert, I would lean to the heavier pills hitting the steel. Even though you say you plan on hand loading for everything, there are a lot of great factory ammunition sources for the Grendel. I got into it thinking I would exclusively hand load as well, and I shoot a lot of factory ammo-have done so for years now.

With Hodgdon's CFE or LeveRevolution underneath the 123gr target and hunting bullets, you can easily get 2600-2650fps with a 20" Grendel. Most of the folks pushing the 6mm's in the AR15 are using as long of a barrel as they can get to break the 2800fps mark with the longer pills with BC's over .500 G1/.250 G7.

 

[nuclear_shooter]

Have you looked at 6mmAR?

Sent from my Nexus 5 using Tapatalk

 

[B.A.C.]

I'm thinking about switching over to a 6x45 after I get some use out of my 223. I probably won't shoot past 300 yards and the only reason I'm considering it is because Iowa requires a 24 caliber or larger for shooting deer. I don't want to mess around with specialty magazines and I've heard the Grendel is notorious for breaking bolts.

 

[steve123]

Have you looked at 6mmAR?

Sent from my Nexus 5 using Tapatalk

^^^

I think if I were to do a 6mmAR over again I'd do the 6mmART non 40 degree version and either shoot the 95 grain Berger VLD or the 105 grain hybrid.

The 224 AR is an even better choice than 6mm IMO. 90's at 2900 fps is doable in a longer barrel or 75 Amax at 3100 fps. Now your getting up into BC's and FPS capable of taking on the likes of 6.5 Creed and such.

 

[nuclear_shooter]

^^^

I think if I were to do a 6mmAR over again I'd do the 6mmART non 40 degree version and either shoot the 95 grain Berger VLD or the 105 grain hybrid.

The 224 AR is an even better choice than 6mm IMO. 90's at 2900 fps is doable in a longer barrel or 75 Amax at 3100 fps. Now your getting up into BC's and FPS capable of taking on the likes of 6.5 Creed and such.

I looked at this as well but didn't think you could load em to mag length.

Sent from my Nexus 5 using Tapatalk

 

[shooter3225]

What's the benefit of 6mmAR over the Grendel? Its a 6.5 necked down to 6mm right, so better choice in bullets with better BC than Grendel, and more capacity than 6x45?

 

[steve123]

What's the benefit of 6mmAR over the Grendel? Its a 6.5 necked down to 6mm right, so better choice in bullets with better BC than Grendel, and more capacity than 6x45?

Same or higher BC but faster by using a lighter bullet = less drop, drift and recoil.

Take for instance a 90 grain Berger VLD with a .55 BC going 2850-2900fps out of a 224AR. Compared to 6.5G with a 123 gr/.52 BC going 2500-2550fps.

The Grendel case holds approx 29 grains of medium burn rate powder. 6x45 holds about 3 grains less. Both of these at mag length.

 

[shooter3225]

I'm going to be shooting closer than that on most occations I would guess 2-500 mostly but occasionally wanting to reach out. That's why I was looking at the 6x45 but the 6mmAR is pretty interesting.

 

[fmsniper]

I am getting 6 inch groups at 1K with a 6.5 Grendel, I kill antelope and deer with it out past 300 yards easy, grat cartridge

 

[jasonfaz]

I'd take my 6.5 G over just about anything if it's getting the furthest effective range as possible out of the AR15 in a hunting application. I'm not sure I would compare powder capacity of the two cases at "mag length" considering there are many mfg'ers out there making mags that will feed a COAL up to 2.3" compared to the PMag's 2.250". More importantly, even with a 2.8" COAL I'm having zero issues running 123 gr Scenars (.527 BC) and.......wait for it..... the 129 gr Nosler AccuBond LR (.561 BC). Hell, even Hornady factory loads their 129 SSTs for the 6.5G now. That Nosler is going to buck wind 3-4 inches better than the skinny 87 grainer. The terminal performance wouldn't even be worth comparing between the two. The 6.5G with std loads will have an effective range past 600. Mine was built specifically for Idaho Grey wolf. If I end up seeing one at 800 I'm still going for the shot...

 

[shooter3225]

Nice rifle Jason! All things considered what's the barrel life difference on average b/w these two rounds..just curious. A lot of love it seems for the 6.5

 

[BoilerUP]

I'd have to think 6x45 would have longer life than a Grendel...not that the Grendel is remotely a barrel burner given capacity-to-bore.

 

[LRRPF52]

Jasonfaz, that rifle is sick! There is an Alexander Arms factory hunting load with the 129gr Hornady SST that has been around since the Grendel was brought to market, and the new Hornady factory load is the 123gr SST with .510 BC. I just got a case of them for $17.99 per box of 20 from Selway Armory, with 2 days no BS shipping BTW.

I'd have to think 6x45 would have longer life than a Grendel...not that the Grendel is remotely a barrel burner given capacity-to-bore.

6x45 will have a lower barrel life due to pressure. Fast burning powders combusted at high pressures will erode the throat faster, although I doubt there are a lot of high volume 6x45 shooters out there. Either way, the lower pressures of the Grendel lead to unusually long throat and barrel life, especially when you start looking at the really efficient powders, such as H335.

 

[SRSDriver]

Jasonfaz, that rifle is sick! There is an Alexander Arms factory hunting load with the 129gr Hornady SST that has been around since the Grendel was brought to market, and the new Hornady factory load is the 123gr SST with .510 BC. I just got a case of them for $17.99 per box of 20 from Selway Armory, with 2 days no BS shipping BTW.



6x45 will have a lower barrel life due to pressure. Fast burning powders combusted at high pressures will erode the throat faster, although I doubt there are a lot of high volume 6x45 shooters out there. Either way, the lower pressures of the Grendel lead to unusually long throat and barrel life, especially when you start looking at the really efficient powders, such as H335.

I'm loving my new Grendel - Does anyone know the actual difference between the hornady factory 123g SST load and the hornady factory 123g AMAX Load? Looking up the projectiles they both have a BC of 0.510...

 

[*Nine]

I had a 6mmAR for a while, it was great. Slinging the .530BC Hornady 105 bullets at 2770 out of a 24" barrel was no problem and the rounds fed great from the magazine. In a 6.5 Grendel the high BC bullets (the heavy/long 140ish grain stuff) won't fit in a magazine so you're stuck shooting the lower BC stuff slower than the 6mm variant can push the 105s.

 

[45ar]

I got a Grendel barrel when I built my last upper.
I figured the 123SST's would be better past 300 yards over the 6mm 105's for hunting.
Half inch groups are easy using AR Comp.
I'm getting 2550 fps with 123's.
2850 fps with 95 grain V-max's using 2230 or Viht-133.
Get 3/4 inch groups.
I think that's pretty good for an 18 inch barrel.
The 95's at 2850 would slam coyotes.
Going to use them on woodchucks soon.
The most impressive thing I like about the Grendel is it's so accurate.

 

[jasonfaz]

Nobody mentioned any "140 grain stuff". What was mentioned were the 123 gr Lapua Scenar and the 129 gr Nosler AB LR. It was specifically pointed out that those respective BC's are just as high (Scenar w/.527 BC) and higher (Nosler w/.561 BC) than the afore mentioned 87 and 105 gr 6mm. It boils down to terminal performance and wind drift. Terminal performance past 300 is no contest, I feel the heavier projectile with at least an identical BC will buck wind better every time.

 

[*Nine]

Nobody mentioned any "140 grain stuff". What was mentioned were the 123 gr Lapua Scenar and the 129 gr Nosler AB LR. It was specifically pointed out that those respective BC's are just as high (Scenar w/.527 BC) and higher (Nosler w/.561 BC) than the afore mentioned 87 and 105 gr 6mm. It boils down to terminal performance and wind drift. Terminal performance past 300 is no contest, I feel the heavier projectile with at least an identical BC will buck wind better every time.

His initial post stated "Will be shooting steel/paper out to 600-700 yards max." and only later did he mention even a possible use on coyotes or varmints, but he still maintained the paper/steel would be the main use. Now, I understand that all else being equal the higher BC is better, but even if he wanted to shoot those $.50/ea Noslers at paper and steel he still can't push them fast enough in the 6.5G for their slightly higher BC compared to the 105s to make up for the fact they'll be going ~250 fps slower than the 105. As for use on varmints or coyotes, there are plenty of excellent bullets for such a task in 6mm.

 

[steve123]

Nobody mentioned any "140 grain stuff". What was mentioned were the 123 gr Lapua Scenar and the 129 gr Nosler AB LR. It was specifically pointed out that those respective BC's are just as high (Scenar w/.527 BC) and higher (Nosler w/.561 BC) than the afore mentioned 87 and 105 gr 6mm. It boils down to terminal performance and wind drift. Terminal performance past 300 is no contest, I feel the heavier projectile with at least an identical BC will buck wind better every time.

Jason,

I just went to JBM calculations and ran the numbers for these parameters in their simple trajectories.

All calculated at 700Y - drop - drift/10mph - energy

6.5G 129SST, .561BC, 2500fps, = 150"- 33.6"- 794

6mmART40 105 Berger hybrid, .545BC, 2850fps = 112"- 28.5"- 858

224AR 90 Berger VLD, .551BC, 2900fps = 108"- 27.4"- 773



That is a very cool AR you have there!!!

I'm not against 6.5G at all, I might even get a upper for convenience sake for now until 5.68DMR comes to fruition.

 

[*Nine]

Indeed, the 105s will more than likely hit with MORE energy at anything past 200 or so and do it with less drop and drift compared to the 120-130gr stuff in the 6.5 Grendel.

I should point out though that cramming a long 105 Hybrid into the 6AR (or similar) case and getting it into a magazine might be a trick. I just stuck with the shorter Hornady 105 (the hpbt match bullet, not the amax) bullets in my 6AR and had great results out past 900 on steel.

 

[LRRPF52]

I'm loving my new Grendel - Does anyone know the actual difference between the hornady factory 123g SST load and the hornady factory 123g AMAX Load? Looking up the projectiles they both have a BC of 0.510...

123gr A-MAX has the new AMP jacket manufacturing process, more uniform lead alloy, and tighter tolerances all around.

123gr SST uses the manufacturing technology from the new production capabilities, but has an interlock jacket and a cannelure, so it is specifically designed to expand and retain weight at the base with the locked jacket, for hunting purposes.

We've seen that the 123gr A-MAX behaves like a Nosler Ballistic Tip on game, and at Grendel velocities, it holds together well, especially when shot with slower mv from a carbine. Long-range effectiveness has been proven on Antelope out to 752yds.

The 123gr SST has a bit of a different ogive shape, which I think is a result of the cannelure forming, and shoots very well. Performance on game has been exceptional, including twofers on hogs, DRT on Caribou at 275yds, and quick kill at 400yds on Caribou from an 18" barrel using factory ammo. The 123gr SST is one of the best dual-use hunting/target bullets currently on the market.

A fellow long range shooter recently used my 16" Grendel with my load of 31.2gr of CFE under the 123gr A-MAX at 2.275" COL to clean a Know Your Limit rack at 500yds.



The SAAMI Grendel throat is very forgiving as to shooting a lot of bullets accurately. This is the gun:

 

[Twelve208]

I have both the 6x45 and Grendel.IMO they are not even in the same class.When I go out and ring steel,the difference in kenetic energy is night and day between the two.Dont get me wrong, my 6X45 is a lazer and fun to shoot.The Grendel is very well suited as a hunting cartridge,and the ultimate wolf hunting gun.I have shot wolves with a 6X45 as well,however the stopping power the Grendel had over the 6X45 was again apples to oranges.Guess it all depends on your stlye of shooting.Mine is hunting,and if there is something out there that has better long range knock down, in a lightweight autolading platform that has 20+ rounds on board..Im all ears.I'm already working on getting a 6 Grendel going,rock chucks will not be too happy about that!
The grendel has proved its worth for me this year.

 

[Scottmilk9]

^^^ what he said, minus the wolf hunting. My buddys son took a cow elk with a 6.5 grendel and dropped it in its tracks.

 

[Twelve208]

^^^ what he said, minus the wolf hunting. My buddys son took a cow elk with a 6.5 grendel and dropped it in its tracks.

Speaking about getting a 6 grendel in the works...

 

[lte82]

6 fat rat is what I'm going with with my 6AR turbo 40 barrel wears out. They are nearly the same cartridge, just the fat rat barrels are cheaper to get.

Oh, and they absolutely hammer with very little recoil with the 105 vld. Amazing little round.

 

[BERTMAN77MK2]

The Grendel is a fantastic long range round and the fact that is in a std AR15 chassis makes it even more endearing. I have many other uppers that I would absolutely hate to give up but would be okay if I were limited to only one---a Grendel. I like all the calibers for their specific uses but can use the 6.5 for almost anything I would encounter. I was ecstatic when it became a SAMMI round so more people could discover its versatility. Most all the other rounds mentioned are favorites for a particular task. My EDC AR is a 14.5 Grendel, though I have 18 and 22 also. I think the 6X45 is a phenomenal varmint (up to coyote) round that is superbly accurate and easy to reload for. And I do plan to try the 6mmFatRat (after I finish 9mm and 300 BO uppers). Interested in that .22Grendel round for varmints also but my .204 is a riot on prairie dogs and such! I have JP, Les Baer, and Alexander 6.5 bolts and have never had any problems thus far. I got "wolves" on my bucket list of Grendel targets!

 

[jasonfaz]

Steve, you do realize youre comparing the 6mmAR Turbo with data derived from a 30" tube to a grendel with a 20" tube. Not sure why people even consider a 30" barrel on an AR in the first place, but it happens. Even the 6mmAR data is coming from a 26" bartlein. No f'in way. My rig is shorter WITH the can. The 105gr vld hybrid has overwhelmingly been considered a projectile that wont reliably feed in an AR. The best you'll do is the .530 A-MAX if you wanted to make it a legitimate comparison. You also pushed down the velocity a 6.5G is going to push a 129gr (the 129 gr SST does not have a .561 BC, it has a .485BC). As was previously mentioned, a 20" 6.5G will easily push a 129 gr projo faster than 2500, but I understand that pushing it to that level made your case a little better. Here's what I come up with based on my real data from an 18" 6.5G and spreadsheet data using what is considered the highest BC projo for a 6mmAR out of a SA platform (albeit a 26" barrel):

Input Data:
Wind: Full value wind at 10mph
Pressure: 29.92InHG
Zero: 200 yds
Sight CL Height: 1.18"
Temp: 45F
Altitude: 6500 ft (i live in CO)
Drop & Drift at: 700 yds

Note* 6mmAR tests with 26" Bartlein on 6mmAR.com resulted in an AVERAGE velocity of 2767fps pushing 105 gr Berger BT-M. Using 2700 as an ultraconservative estimate of what you would get out of a 22" rather than the traditional 20fps per inch of barrel. That way it'll at least get close in length and we dont have to factor in lugging around rifles that are 6 feet long. Further, ill use the better .530 BC of the A-MAX in calculations. I'm using Bullet Flight:
Drop: 115.5"
Drift: 32.0"

6.5 Grendel 129 gr Nosler AB w/.561 BC at 2625fps:
Drop: 120.2"
Drift: 31.2"

Drop is fixed and no issue, its wind that I want to buck and the 6.5 does it better in a compact package than does a 6mmAR. With respect to energy, try taking into account John Taylor's KO formula and factor in momentum (or get in the field and see what happens). You'd see the same as myself, overwatcher and LRRP have seen. Using Taylor's formula the 6mmAR is putting out no more than 75% of the energy a 6.5 G does. Generally speaking, heavier weight maintains energy downrange better than light weight and that doesnt change here either. I also never mentioned anything about energy. I did, however, mention that terminal performance would not be anywhere near the same. Obviously, one would see significant difference in terminal performance when using projectiles designed for target shooting when compared to projectiles designed for hunting.

The KO formula is available through JBM btw. Go give it a looksie and enjoy. One last thing, do you really shoot an AR with a 30" pipe? If so i bet you conceal carry a 22lr like this right?
SilencerCo: The Wizard Staff - YouTube

 

[jasonfaz]

Overwatcher,
NICE round up my man!! What GMU did you hit? I am trying to talk myself out of heading all the way up to Lolo - the only place I had any luck - once everything opens back up. I was dissappointed to see the early Mar 31 close dates. I was used to going for spring bear and would just grab my wolf tags at the same time. Season got 2 months shorter all of the sudden. Heard anything about why that change occurred?

 

[DirtyDave]

I'm going to be shooting closer than that on most occations I would guess 2-500 mostly but occasionally wanting to reach out. That's why I was looking at the 6x45 but the 6mmAR is pretty interesting.

For this and Coyotes thrown in the mix, the 6x45 with 75gr V-max is the ticket. I shoot mine out to 600yds on steel plates just fine.
No need for heavier bullets like 90gr+ in the 6x45

 

[1slow01z71]

With the newish 6.5x6.8 why would you even consider the 6.5 grendel? From what I can tell it basically has all the benefits of the grendel without the bolt shortcomings. I know those have largely been rectified but now theres talk of a new reamer for grendel, is that going through? I dont follow the grendel as I have no real need for one. I like the 22x6.8 personally, 75gr Amaxs are cheap and hang right in there with the grendel with a better bolt design and I've already got 6.8 brass. A 75gr amax at 3200 out of a 24" is pretty tough to beat IMO.

 

[Scottmilk9]

With the newish 6.5x6.8 why would you even consider the 6.5 grendel? From what I can tell it basically has all the benefits of the grendel without the bolt shortcomings. I know those have largely been rectified but now theres talk of a new reamer for grendel, is that going through? I dont follow the grendel as I have no real need for one. I like the 22x6.8 personally, 75gr Amaxs are cheap and hang right in there with the grendel with a better bolt design and I've already got 6.8 brass. A 75gr amax at 3200 out of a 24" is pretty tough to beat IMO.

You should ask, why a 6.5x6.8? The 6.8 and the grendel have theoretically the same case capacity and the grendel has been proven for years. Also, the bolt issue is non-existent. A 75gr amax might hang with a grendel at short and medium distances but guarantee anything beyond 500yds it wont hang, nor will it have any kind of energy.

 

[Twelve208]

6.5x68? With all the commercial backing the Grendel has and now being SAAMI,seems like a winner for anyone starting from scratch and not the wildcatter type.
Another pitfall I see with the x68,is the longer case will not allow for longer bullets, and still be able to load at mag length.Hence the design of the shorter Grendel case that allows for a large variety of bullets.Again I'll be all over it if there is something out there that can beat the Grendel.

 

[Metal Gear]

Fantastic thread gentleman! What a great read during a mid week lunch break while eating my sandwich. I have been pondering up a 20" barrel 223 AR build as of late for my next rifle, but now the 6.5 Grendal has all my attention.

 

[steve123]

Steve, you do realize youre comparing the 6mmAR Turbo with data derived from a 30" tube to a grendel with a 20" tube. Not sure why people even consider a 30" barrel on an AR in the first place, but it happens. Even the 6mmAR data is coming from a 26" bartlein. No f'in way. My rig is shorter WITH the can. The 105gr vld hybrid has overwhelmingly been considered a projectile that wont reliably feed in an AR. The best you'll do is the .530 A-MAX if you wanted to make it a legitimate comparison. You also pushed down the velocity a 6.5G is going to push a 129gr (the 129 gr SST does not have a .561 BC, it has a .485BC). As was previously mentioned, a 20" 6.5G will easily push a 129 gr projo faster than 2500, but I understand that pushing it to that level made your case a little better. Here's what I come up with based on my real data from an 18" 6.5G and spreadsheet data using what is considered the highest BC projo for a 6mmAR out of a SA platform (albeit a 26" barrel):

Input Data:
Wind: Full value wind at 10mph
Pressure: 29.92InHG
Zero: 200 yds
Sight CL Height: 1.18"
Temp: 45F
Altitude: 6500 ft (i live in CO)
Drop & Drift at: 700 yds

Note* 6mmAR tests with 26" Bartlein on 6mmAR.com resulted in an AVERAGE velocity of 2767fps pushing 105 gr Berger BT-M. Using 2700 as an ultraconservative estimate of what you would get out of a 22" rather than the traditional 20fps per inch of barrel. That way it'll at least get close in length and we dont have to factor in lugging around rifles that are 6 feet long. Further, ill use the better .530 BC of the A-MAX in calculations. I'm using Bullet Flight:
Drop: 115.5"
Drift: 32.0"

6.5 Grendel 129 gr Nosler AB w/.561 BC at 2625fps:
Drop: 120.2"
Drift: 31.2"

Drop is fixed and no issue, its wind that I want to buck and the 6.5 does it better in a compact package than does a 6mmAR. With respect to energy, try taking into account John Taylor's KO formula and factor in momentum (or get in the field and see what happens). You'd see the same as myself, overwatcher and LRRP have seen. Using Taylor's formula the 6mmAR is putting out no more than 75% of the energy a 6.5 G does. Generally speaking, heavier weight maintains energy downrange better than light weight and that doesnt change here either. I also never mentioned anything about energy. I did, however, mention that terminal performance would not be anywhere near the same. Obviously, one would see significant difference in terminal performance when using projectiles designed for target shooting when compared to projectiles designed for hunting.

The KO formula is available through JBM btw. Go give it a looksie and enjoy. One last thing, do you really shoot an AR with a 30" pipe? If so i bet you conceal carry a 22lr like this right?
SilencerCo: The Wizard Staff - YouTube

LOL, yep that's how my upper looked except my scope was bigger but the 6mmART40 did make me feel supernaturally endowed at times, smile.


The reason I had my heavy and long 6mmART40 upper was for competition, both field course and tactical. I agree it wasn't practical for hunting Yotes although I did kill a bunch of PD's and a few Yotes with it. 105 Amax put both Yotes down hard at a RF'ed 333Y that's for sure!

I had the 6mmART40 with a 26" Krieger and shot two different 6.5G's, one in 24" and the other in 20". I only have experience with a few AR's in a few of these cartridges. 223, 6mmART40, 6.5G and 5.68DMR.

I shot side by side using my 6mm against both 6.5's on a couple different occasions. My loads were 105 Amax or 105 JLK's at 2875 fps. Their's were normal fps for 6.5G with 107's and 123's. I'll just say that the 6mmART40 was noticeably superior than my friends 6.5G's in the wind. It was much easier for me to hit steel at longer distances. Heck, I've even won a few long range matches with mine competing against 243, 260 etc. I know I could not have done that if I were shooting a 6.5G, at least with their rifles and loads. One time I watched a friend who had borrowed my 6mmART40 hit a 10" plate at 809Y six times in row while the rest of us with our flat shooting bolt guns couldn't repeat his performance in the same conditions, this was in 5-10 mph winds. Honestly I'd put that 6mmART40 closer to my 6x47L vs 6.5G.

Berger 105 vld's fed fine in my rifle, I sold it before 105 hybrids were available and had not heard that they do not feed well. Anyway there isn't much difference in BC between the two. Even though it is a crappy powder (AA2520) I was able to push 105 Bergers at 2925 fps in summer, come winter the velocity dropped 125 fps so I quit using it. Thought I'd mention this.

Yes I agree on the barrel length comparison. 6.5G would be closer in velocity compared to the other cartridges mentioned using shorter barrels. I'll say this...if you are pushing 129's at 2625fps out of a 20" then that has got to be a 60,000 plus psi load. I'll also stick with my 2500 fps estimate as a normal expected velocity for 6.5G with 129's.

I didn't fire the 5.68 DMR but 80 rounds. It had the recoil of a 223 with heavy bullets, pretty sweet! 2820 fps with 90's was a medium load, this was in a 24" barrel. The inventor of the cartridge has found a good load at 2900 fps using 90's with a different powder than I was using. I'm not into hunting all that much so this is the cartridge that suits me the best for a long range AR cartridge. In other words KO is of no consequence to me. Since my 223 is 15" I'll get the 5.68 in 20".

 

[LRRPF52]

If we're looking at 129gr SST speeds in the Grendel, 2662fps from a 24" is about the fastest I have seen, .7gr below max load in Hornady's 9th Edition, which used an 18" barrel. The 8th Edition used a 14.5" barrel. The 129gr SST isn't the bullet to compare for target work, as it has a lower BC than the 123gr stuff.

I'm not sure we can extrapolate data from the 129gr SST over to the 129gr ABLR, as the ABLR has some pretty soft jacket material, which will build pressure fast. The ABLR also has a very long bearing surface to it, and is meant to expand down to some pretty low impact velocity thresholds. Another bullet in that weight range is the 130gr Swift Scirocco, but it builds pressure quickly too, and is limited to around 2400fps in most of the data on hand from 24" guns.

123gr is really a good balancing point for the Grendel and target work, unless you're shooting closer distances and want more speed, where the 107gr SMK might make more sense. CFE223 has really changed things a bit for speeds, with respectable ES's, and my little 16" held its own at 500yds on the KYL rack next to .260 Remington's, although the impact energy was night and day difference between a 123gr Scenar going 3100fps mv from a 26" bolt gun, or a 142gr SMK going 2740fps from a 22" AR10, compared to a 123gr A-MAX from a 16" Grendel at 2500fps.

 

[5spd]

Between just the 6x45 & Grendel Id go 6x45.
I built a 6x45 bolt gun, 24" bbl after I sold my AR15 in 6x45, 20: bbl since that was just darned accurate, but wanted a much more accurate build and that's on a bolt action.
I run my 6x45 with a nosler 95g HBT bullet to 700 yards and average 4.5"-6" groups at a 2718 fps.
All my 100 yard 6x45 groups run .510" on average with the 55-95g bullets and that's perfect for my usages.
My basic load is the 65g vmax at 3142 fps, 479 coyote shot with that combo in 4 years.
Every Grendel to date I have seen at the range has run into feed issues/ FTF/ FTE/jambed and other loading issues to make me never want to think about having one in that caliber.
That said, IMO most problems are man made from the end users, not the AR platform its self or for that fact the caliber.
I also built a 6x6.8 that runs even better than my 6x45, but that's another story.
I have taken 8 antelope with my 6x45 a using 85g & 95g bullets to 400 yards.

 

[346ci]

If you are looking at running factory ammo most of the time, .264LBC or the G for sure. My .264gARP was a tack driver with the 123gr Amax, wish I would have kept it.

If you want to get into reloading, the sky is the limit for the wildcats. The 6x6.8 or 6.5x6.8 would be my choice, being a 6.8 guy and having lots of 6.8 brass. Using a ARP superbolt, you would not have bolt issues.

I've seen a 6X45 school some bigger calibers also, that would be my 2nd choice.

 

[1slow01z71]

You should ask, why a 6.5x6.8? The 6.8 and the grendel have theoretically the same case capacity and the grendel has been proven for years. Also, the bolt issue is non-existent. A 75gr amax might hang with a grendel at short and medium distances but guarantee anything beyond 500yds it wont hang, nor will it have any kind of energy.

Nonexistent bolt issue? A quick search of the internet says otherwise. Obviously bolts have gotten better so its not nearly the problem it used to be but to say its imaginary is a lie. You should run the numbers a 75gr amax at 3200fps is not very far at all behind many of the grendel loads. If youre shooting game animals past 500yds with a grendel then that tells me all I need to know about you. 75gr amax out of a 223 still splashes just fine on steel at 800yds and that load is way behind any of the cartridges discussed in this thread.

Maybe I'm a hater but I've never seen the point of shooting expensive compared to 223 bullets out of a grendel when you get a lot more performance out of that same bullet in a creedmoor or 260. With the DPMS G2 out now if it works out almost all of these long range variants on borrowed time. I just like the idea of a 22x6.8 as the 75gr amax is the cheapest long range bullet out there. Long barrel life, 25% less powder than the big cartridges, cheap bullets 17ish cents a bullet and hangs right there with the bigger boys in everything except energy on target way on out there. Although I'd hope no one is using these wildcats on game animals at the 500+ yard distance that there starts to be any real appreciable difference between them.

 

[jasonfaz]

WTF? What bolt issues are you referring to? There are two different chambers offered up for 6.5Gs requiring two different bolts. Ive heard of no issues with either in terms of reliability. As for the comments about taking game at 500+ yards I take personal offense to. I consider myself a very ethical hunter in all regards. I've passed up shots at least 20 times based on the fact I don't know for sure that I can make a hit at a given distance. That said, I've worked my ass off gaining proficiency around reading wind and drop and shoot enough that I'm 100% comfy shooting at 500-700 with a 6.5 on 200-250lb game. No issue there. Not sure what you mean by saying "if you're shooting game animals at 500+ I already know who you are" means, but if you're implying its unethical in anyway I'd recommend you get a little time under your belt shooting at distance with the appropriate tools for the job before you go bitching at people for something they've worked long and hard to accomplish...

 

[jasonfaz]

That was directed towards 1slow01z71 if the name didn't speak for itself....