Barrel Length

[twentyeggs]

Hey all how’s it going!

I am in the middle of doing my first 30 caliber build. It is going to be a dedicated long range build. I want something that uses fairly common loads, not overly expensive to shoot, but will reach out as far as possible. I choose 6.5 creedmore. I can do as much practice as I want shooting 7.62x39mm and enjoy the availability of such rounds. Or switch over to 6.5 CM and stay supersonic all the way up to the 1 mile mark. Although I will probably keep the range for this gun around 1,000 yards. I’ve got my eye on the 300wm or 338 NEMO rifles if I really start getting into ultra long range shooting.

So my question is what to look for when selecting a barrel. One of the big questions is what length should it be? I hear people say 20” is perfect, others say 18” is best, and the others who say 20” should be the minimum. I am not really looking for portability. I don’t plan to carry it anywhere other than from car to bench. I am looking for best accuracy. I

Then twist rate. I will be shooting the heaviest options for either 308 or 6.5CM.

material, manufacturing process ect..

Lastly I don’t want to fall into the marketing trap. I’m looking for a nice quality barrel (and bolt), but don’t want to over spend for something that has a comparable option priced much more reasonably. I’m expecting the barrel to be about 60-80% the cost of the entire build, excluding the optic. Lord have mercy I will be putting a Vortex or Leupold scope on this build. So I don’t want to think about that just yet.

If you made it this far, thanks for reading. Any advice, info, opinions, recommendations are appreciated.

 

[2grim4U]

Depends on how heavy of a weapon you want to deal with. The extra length helps velocity, but doesn't do anything for precision/accuracy.

Barrel twist rate depends on the sectional density of the bullet you intend to use. Long skinny bullets (like a 200+ gr 30 cal bullet) need a faster twist rate to stabilize than a short fat bullet.

You're asking some pretty broad questions. You need to do some research and have a better definition of what your goals are. Mixed use? Dedicated competition platform? Plinker? Hunting? Or something you just want to impress your friends with?

Selecting a faster twist rate will only broaden the range of projectiles you can use. Lots of options on quality barrels. Before you can choose anything you need to have a range of precision your looking to achieve. Lot's of cheap barrels can shoot 2" groups at 100 yards. Start talking about .5" groups, and plan on prices to go up four fold.

Material, post machine finishing, manufacturing process all revolve around your budget and what you're expecting to achieve.

 

[MNhunter1]

If I was looking at 1000 yds in a 6.5 or 308, with no need for portability, I'd go 24"-26" in a heavier profile, rifle length or + on the gas system. The only reason I personally see to go any shorter is for weight savings and/or mobility.

 

[twentyeggs]

If I was looking at 1000 yds in a 6.5 or 308, with no need for portability, I'd go 24"-26" in a heavier profile, rifle length or + on the gas system. The only reason I personally see to go any shorter is for weight savings and/or mobility.

What are the advantages/reason behind going rifle length on the gas system? Does it have to do with the length of the barrel? I was also planning to do an adjustable gas block.

do you know off hand the length of barrel where it starts to negatively impact ballistics?

Thanks for the reply!

 

[acudaowner]

6.5 Creedmoor- Effect of Barrel Length on Velocity: Cutting up a Creedmoor!

Since its introduction by Hornady in 2007, the 6.5 Creedmoor (sometimes shortened to Creed) has established a strong foothold in the US rifle market. The 6.5 Creedmoor balances the excellent exter…

rifleshooter.com

 

[twentyeggs]

Depends on how heavy of a weapon you want to deal with. The extra length helps velocity, but doesn't do anything for precision/accuracy.

Barrel twist rate depends on the sectional density of the bullet you intend to use. Long skinny bullets (like a 200+ gr 30 cal bullet) need a faster twist rate to stabilize than a short fat bullet.

You're asking some pretty broad questions. You need to do some research and have a better definition of what your goals are. Mixed use? Dedicated competition platform? Plinker? Hunting? Or something you just want to impress your friends with?

Selecting a faster twist rate will only broaden the range of projectiles you can use. Lots of options on quality barrels. Before you can choose anything you need to have a range of precision your looking to achieve. Lot's of cheap barrels can shoot 2" groups at 100 yards. Start talking about .5" groups, and plan on prices to go up four fold.

Material, post machine finishing, manufacturing process all revolve around your budget and what you're expecting to achieve.

The purpose of this gun is to take long range shots: over 500 yards. I’ve got other guns to go plinking, hunting, and competition with. I am just getting very interested in long range shooting and want to start attending classes. Eventually I’ll want to take one of those mile long shot classes but I have a ways to go before I am proficient enough to take that shot with any confidence- no luck involved. So this guns purpose is to allow me to practice the basics to advanced techniques.

I’ll be hand loading my ammo with Hornaday A-Tips for those shots but I also don’t want to eliminate the ability to shoot 123gr 7.62x39 either. I am a bit confused with twist rate. I mean I understand the general thumb, faster twist rate for heavier loads and slower for light. And for .223 it’s pretty basic, 1:7 for 70-85+gr, 1:9 for 45-75gr.
But the differing and inconsistent information out there for 308 is confusing me.
for example, one website says:
1:12 for 110-147gr
1:11 for 147-175gr
1:10 for 175+gr
And then Hornaday throws me for a loop with their own recommendations for the A-tip rounds with:

1:8.5 for the 135gr
1:8 for the 150gr
Then go the opposite direction:
1:9 for the 230gr
And then they go back again to
1:8.5 for the 250gr
Like what???

And then how much dbarrel length affect twist rate. Between a 16” and 24” barrel you could have an entire extra revolution.

I would like to shoot the 230/250gr A Tips, since they have a BC of 0.878 but I’m pretty sure that would rule out being able to shoot the normal .123gr loads that are readily available. A more likely spread would be to top out at the 150gr which has a BC of 0.704 at 2,850fps vs the 2,400fps of the 250gr.

I am new to all this ballistic stuff but the goal here is to be able to shoot the fastest flattest line possible while retaining the ability to shoot the readily available 7.62x39 ammo. So I am trying to figure out what sort of compromise I will be settling for, the minimum and maximum weight/gr

 

[Yondering]

I am new to all this ballistic stuff but the goal here is to be able to shoot the fastest flattest line possible while retaining the ability to shoot the readily available 7.62x39 ammo. So I am trying to figure out what sort of compromise I will be settling for, the minimum and maximum weight/gr

What exactly do you mean by "while retaining the ability to shoot the readily available 7.62x39 ammo"? You're talking about choosing a 6.5 Creedmoor, but also talking about a 30 caliber build, and seem to be all over the map here. Are you talking about building a 7.62x39 to shoot long range with heavy bullets?

Or are you so new at this that you think you can shoot 7.62x39 in a 6.5 Creedmoor? No offense intended; I really can't tell.

I thought at first that you wanted to build a 6.5 Creedmoor for long range and will shoot 7.62x39 in a different rifle for shorter range, but your last comment seems to indicate otherwise.

 

[twentyeggs]

Ah shoot.. yeah this is the inexperience showing. I’ve never owned a 30 caliber rifle before and am just starting my research on it. For some reason I was confusing the ability of the AR10 rifle to shoot the 6.5 CM with just a barrel swap with it being able to shoot both rounds. I see now that the 6.5 is slightly smaller in length and diameter. I’m not sure where I got the idea they could be interchangeable like the .223/5.56

Ok that simplifies things a bit. I’m just going to go back an edit the last post and paste it below lol...

The purpose of this gun is to take long range shots: over 500 yards. I’ve got other guns to go plinking, hunting, and competition with. I am just getting very interested in long range shooting and want to start attending classes. Eventually I’ll want to take one of those mile long shot classes but I have a ways to go before I am proficient enough to take that shot with any confidence- no luck involved. So this guns purpose is to allow me to practice the basics to advanced techniques.

I’ll be hand loading my ammo with Hornaday A-Tips for the 1,000+ yard shots to keep things consistent. However I am a bit confused with twist rate. I mean I understand the general thumb, faster twist rate for heavier loads and slower for light. And for .223 it’s pretty basic, 1:7 for 70-85+gr, 1:9 for 45-75gr.
But the differing and inconsistent information on Hornadays website is throwing me for a loop. Here with their own recommendations for the A-tip:

1:8.5 for the 135gr
1:8 for the 150gr
Then go the opposite direction:
1:9 for the 230gr
And then they go back again to
1:8.5 for the 250gr
Like what???

And then how does barrel length affect twist rate. Between a 16” and 24” barrel you could have an entire extra revolution. Will the barrel length determine what is the best twist rate for the ammo I’ll be using?
Say I plan to shoot mainly 125-135gr ammo. Would I choose a 1:8 twist for both a 16” barrel and a 24”? Or go 1:9 since the billet will spend more time getting spun in the longer barrel?

What exactly do you mean by "while retaining the ability to shoot the readily available 7.62x39 ammo"? You're talking about choosing a 6.5 Creedmoor, but also talking about a 30 caliber build, and seem to be all over the map here. Are you talking about building a 7.62x39 to shoot long range with heavy bullets?

Or are you so new at this that you think you can shoot 7.62x39 in a 6.5 Creedmoor? No offense intended; I really can't tell.

I thought at first that you wanted to build a 6.5 Creedmoor for long range and will shoot 7.62x39 in a different rifle for shorter range, but your last comment seems to indicate otherwise.

 

[cleric]

Barrel length is a velocity vs maneuverability trade off. for you situation you don’t care about maneuverability but you do want max range so I would tend toward the longer side 20-24 inches. Someone posted the link earlier to show you how much velocity you are going to get with different lengths.

most of the longer barrels will have rifle or +2 systems. There is different length gas tubes for different barrel lengths, to optimize the rifle

you Could build a separate 308 upper if you a wanted both.

 

[GUNNER10]

Slow down... you are all over the place...

So you are interested in a Large frame AR in 308 and 6.5cm, Are you planning on building up two separate uppers or are you planning on pulling the barrel when you want to change calibers?

With that being said, understand that when loading ammo for Gas guns you are going to be restricted rounds that can fit in the mags, While I have not done any experimenting with the 150/230/250 gr A-tips, they are pretty long bullets and I am not sure they are going to play well jammed into the case in order to make oal.

for practical uses, unless you are shooting to the outer edges of the rounds capability, the average person is not going to see a difference between say a 1:10 vs 1:12 at 800 yards in 308.

I would recommend not overthinking alot of this stuff and just build or buy a solid rifle to figure out what works for you. Find something with an 18 to 20 inch barrel and get out there and shoot.

 

[oniak]

If your going 6.5 CM, I would do 18” if compactness is a priority, otherwise 22”.

 

[twentyeggs]

Slow down... you are all over the place...

So you are interested in a Large frame AR in 308 and 6.5cm, Are you planning on building up two separate uppers or are you planning on pulling the barrel when you want to change calibers?

With that being said, understand that when loading ammo for Gas guns you are going to be restricted rounds that can fit in the mags, While I have not done any experimenting with the 150/230/250 gr A-tips, they are pretty long bullets and I am not sure they are going to play well jammed into the case in order to make oal.

for practical uses, unless you are shooting to the outer edges of the rounds capability, the average person is not going to see a difference between say a 1:10 vs 1:12 at 800 yards in 308.

I would recommend not overthinking alot of this stuff and just build or buy a solid rifle to figure out what works for you. Find something with an 18 to 20 inch barrel and get out there and shoot.

Yes, I will be building two uppers (minus the BCG, Charging handle and possibly handguard). The thing is I am kinda planning to shoot to the outer edge of the rounds capabilities. At least far enough that I might as well get the twistrate right for each round. I’ve got a property where I have a bunch of targets set up and that I am currently planning to set up plates at 100, 200, 500, 800, and 1000 yards. And then there’s another close by where I have permission to set up a few plates, I’m planning on 800, 1500, and 1760 yards when I get proficient at my own 1,000 yard target. I’ll probably stay within 500-800 yards with the 7.62 upper as I’m learning and then continue on with the 6.5CM.

thanks for the replies! I think I’ve settled on 24” I’ve been looking at a few brands and Criterion and BSF have some 24” barrels that look great. I was also told Krieger has great barrels but it seems they are specific to certain bolts and uppers... however there is an option to have the chamber cut by your own gun smith, does that option allow you to fit it to your own setup, like Aero upper and say I donno toolcraft BCG, I haven’t figured out yet which bcg/firing pin will work with both 7.62 and 6.5CM. I hear there is an issue with piercing primers if you don’t get it right. But I also don’t want a cheap BCG that can handle both if there are better quality/higher accuracy ones out there that are specific to each caliber; I’ll just buy two if that’s that case.

 

[BikePilot]

For your uses I think a 6.5cm bolt gun might make more sense. Large frame ARs are awesome, but a bit hard to shoot and for dedicated long-distance stuff a bolt gun is easier imo.

For length in 6.5cm I'd go at least 22" and ideally 24" in a gas gun or 26-28" in a bolt gun. Large frame stuff is not totally standardized, but generally parts fit either AR10 or DPMS patterns. The bolt will need to be headspaced to the barrel regardless of what parts you buy. For barrels JP, Craddock, Krieger, etc. are well regarded. You can't go wrong with JP BCGs. You'll need to pay attention to your gas setup, carrier weight, and buffer weight as it all needs to work together. I'm far from expert in actually getting this right. With 6.5cm you'll want a Rifle +2" gas system I think. That's a lot of barrel and 6.5cm runs pretty high pressure, so moving the gas port out helps keep from over-gassing.

 

[twentyeggs]

Well I am pretty well set on a semi auto for this build/purpose. Ill eventually build a bolt gun in 300 win mag or .338 lapua, probably from a remington 700.

The general consensus is 24" for my barrel length and I'm good with that length. But in coming to that conclusion I now have more questions, mainly on compatibility. I did look into twist rate and barrel length. The length does not affect twist rate. Which surprised me. I thought bullets gradually sped up (rpm) as it travels down the barrel, spinning the fastest, up to the twist rate, as it leaves the muzzle. Which isn't true. The bullet actually spins the twist rate of the barrel from start to finish (exiting the muzzle).

As for the compatibility issues I think I'm just going to start a new thread.

 

[GUNNER10]

Yes, I will be building two uppers (minus the BCG, Charging handle and possibly handguard). The thing is I am kinda planning to shoot to the outer edge of the rounds capabilities. At least far enough that I might as well get the twistrate right for each round. I’ve got a property where I have a bunch of targets set up and that I am currently planning to set up plates at 100, 200, 500, 800, and 1000 yards. And then there’s another close by where I have permission to set up a few plates, I’m planning on 800, 1500, and 1760 yards when I get proficient at my own 1,000 yard target. I’ll probably stay within 500-800 yards with the 7.62 upper as I’m learning and then continue on with the 6.5CM.

thanks for the replies! I think I’ve settled on 24” I’ve been looking at a few brands and Criterion and BSF have some 24” barrels that look great. I was also told Krieger has great barrels but it seems they are specific to certain bolts and uppers... however there is an option to have the chamber cut by your own gun smith, does that option allow you to fit it to your own setup, like Aero upper and say I donno toolcraft BCG, I haven’t figured out yet which bcg/firing pin will work with both 7.62 and 6.5CM. I hear there is an issue with piercing primers if you don’t get it right. But I also don’t want a cheap BCG that can handle both if there are better quality/higher accuracy ones out there that are specific to each caliber; I’ll just buy two if that’s that case.

For a gas gun, twist rate really not going to have a substantial impact on what your doing.

Are you planning on single or mag loading?

 

[Yondering]

Ah shoot.. yeah this is the inexperience showing. I’ve never owned a 30 caliber rifle before and am just starting my research on it. For some reason I was confusing the ability of the AR10 rifle to shoot the 6.5 CM with just a barrel swap with it being able to shoot both rounds. I see now that the 6.5 is slightly smaller in length and diameter. I’m not sure where I got the idea they could be interchangeable like the .223/5.56

Ok that simplifies things a bit. I’m just going to go back an edit the last post and paste it below lol...

The purpose of this gun is to take long range shots: over 500 yards. I’ve got other guns to go plinking, hunting, and competition with. I am just getting very interested in long range shooting and want to start attending classes. Eventually I’ll want to take one of those mile long shot classes but I have a ways to go before I am proficient enough to take that shot with any confidence- no luck involved. So this guns purpose is to allow me to practice the basics to advanced techniques.

I’ll be hand loading my ammo with Hornaday A-Tips for the 1,000+ yard shots to keep things consistent. However I am a bit confused with twist rate. I mean I understand the general thumb, faster twist rate for heavier loads and slower for light. And for .223 it’s pretty basic, 1:7 for 70-85+gr, 1:9 for 45-75gr.
But the differing and inconsistent information on Hornadays website is throwing me for a loop. Here with their own recommendations for the A-tip:

1:8.5 for the 135gr
1:8 for the 150gr
Then go the opposite direction:
1:9 for the 230gr
And then they go back again to
1:8.5 for the 250gr
Like what???

And then how does barrel length affect twist rate. Between a 16” and 24” barrel you could have an entire extra revolution. Will the barrel length determine what is the best twist rate for the ammo I’ll be using?
Say I plan to shoot mainly 125-135gr ammo. Would I choose a 1:8 twist for both a 16” barrel and a 24”? Or go 1:9 since the billet will spend more time getting spun in the longer barrel?

OK that clears things up a little.

For clarity - 6.5 Creedmoor is a "large frame AR" cartridge like the 308 Win (AR10 or DPMS LR308, like a big block Chevy), while the 7.62x39 is a "small frame" cartridge like the 5.56 (AR15 and AK-47, like a small block Chevy) although not a great AR choice IMO, see more below. Comparing to 6.5 Creedmoor, perhaps you confused the 7.62x39 AK round with the 7.62x51 (308 Win) round? Or if you were thinking small frame all around, maybe you confused the 6.5 Creedmoor with the 6.5 Grendel? (The Grendel is another small frame round, with a case derived from the 7.62x39 AK round by way of the 6mm PPC.) Hope that doesn't just confuse the issue more.

Another detail - 7.62x39 has a slightly different 30 cal bore size than the American 30 calibers like 7.62x51/308, 30/06, etc, so it doesn't use the same bullets. The 6.5mm bore size uses .264" bullets.

When considering "cheap to shoot", consider the 6.5 Grendel - most of the good ammo is still fairly expensive, but Wolf FMJ steel case ammo is (or was pre-panic) very cheap at $5-$6 per 20 rd box. Apparently it's become a common AK chambering as well in the eastern Europe and Russian countries, hence Wolf's involvement. It makes sense, since the Grendel can use the same bolt as the 7.62x39 (there are bolt depth differences in ARs, but that's a side note) and just requires a straighter magazine and different barrel.

Notice how 7.62x39 AK47 magazines have a lot of curve to them, like a banana? That's because the case body has a lot of taper, and that's what makes it a less desirable cartridge in an AR15. The AR magazine well is fairly straight, so the top ~10 rounds or so of the mag can't be as curved as it should be. There are (or have been) AR15 lowers made specifically for this cartridge that use a more curved magazine, but those lowers are non-standard and don't fit other cartridges as well.

Something else to know - once you get on the same page of looking at cartridges of the same frame size, you can change calibers by swapping barrels, but it's not something you would do on a regular basis. Instead, you'd swap complete uppers, along with any necessary magazine changes. You'll eventually figure out though that while just swapping uppers sounds reasonable, it's better to just add another lower and have two complete rifles. A lower set up for long range is not usually ideal for a short range knock-around blaster anyway.

On twist rate - for the 6.5 Creedmoor, 1:8 is generally the accepted twist rate, although going a little faster twist like 1:7 or 1:7.5 etc is fine. Twist rate requirements are based on bullet length, not weight, so you can't really compare twist rate values across different calibers. Longer bullets need faster twist (1:8 is faster twist than 1:10, etc.)

Hope that helps. Now that we're getting this stuff cleared up, could you tell us about your background, and why the sudden interest in this stuff? Thanks!

 

[nn8734]

Well I am pretty well set on a semi auto for this build/purpose. Ill eventually build a bolt gun in 300 win mag or .338 lapua, probably from a remington 700.

The general consensus is 24" for my barrel length and I'm good with that length. But in coming to that conclusion I now have more questions, mainly on compatibility. I did look into twist rate and barrel length. The length does not affect twist rate. Which surprised me. I thought bullets gradually sped up (rpm) as it travels down the barrel, spinning the fastest, up to the twist rate, as it leaves the muzzle. Which isn't true. The bullet actually spins the twist rate of the barrel from start to finish (exiting the muzzle).

As for the compatibility issues I think I'm just going to start a new thread.

Have you actually spent money yet on parts for your build(s)? If yes, ignore the rest of what I’m about to say.

If no, I’d consider buying a later model LMT MWS with stainless 6.5 Creedmoor and .308 Winchester barrels. Barrel/caliber change consists of loosening two fasteners, withdrawing and reinstalling each barrel and takes like 30 sec to a minute. No messing around with building multiple upper receiver groups, etc. Also, the newer MLOK rail versions are a bit lighter than the legacy cheese grater quad rail versions.

Then build a small frame AR set up in a chambering of your choice with none of the complexity that comes with building a large frame.

Just throwing it out there for someone who is so new to the sport, it might save you some frustration and money in the long run while still giving you one hell of a semi auto platform for precision long range.

 

[Baron23]

I'm not a gas gun guy (in rifles that is and that should be a "not yet" and not a "not") and sort of wonder why you want to go in the AR-10 direction if long range shooting is your goal... versus a good bolt gun.

I have a 6.5 CM and the barrel length is 24", MTU contour, with a 7.5" twist and it shoots great...better than I do (ask me how I know this! LOL).

My deer gun, Rem 700 5R in .308, has a 20" barrel for maneuverability considerations. But you said that your goal is long range shooting and portability is not a consideration so I wonder why you are agonizing over barrel length (and yes, I had the same concerns and questions at one point but got over them! haha).

If me, I would go 24-26", heavy contour, and probably an 8 twist.....but I'm NOT one of the experts here so take all of this with a grain of salt.

With that said, I enjoyed seeing @lowlight shooting the Seekins SP-10 and grinning about it. Made me want one. But my competence isn't even in the same universe as Frank and other like him, so there is that.

 

[twentyeggs]

OK that clears things up a little.

For clarity - 6.5 Creedmoor is a "large frame AR" cartridge like the 308 Win (AR10 or DPMS LR308, like a big block Chevy), while the 7.62x39 is a "small frame" cartridge like the 5.56 (AR15 and AK-47, like a small block Chevy) although not a great AR choice IMO, see more below. Comparing to 6.5 Creedmoor, perhaps you confused the 7.62x39 AK round with the 7.62x51 (308 Win) round? Or if you were thinking small frame all around, maybe you confused the 6.5 Creedmoor with the 6.5 Grendel? (The Grendel is another small frame round, with a case derived from the 7.62x39 AK round by way of the 6mm PPC.) Hope that doesn't just confuse the issue more.

Another detail - 7.62x39 has a slightly different 30 cal bore size than the American 30 calibers like 7.62x51/308, 30/06, etc, so it doesn't use the same bullets. The 6.5mm bore size uses .264" bullets.

When considering "cheap to shoot", consider the 6.5 Grendel - most of the good ammo is still fairly expensive, but Wolf FMJ steel case ammo is (or was pre-panic) very cheap at $5-$6 per 20 rd box. Apparently it's become a common AK chambering as well in the eastern Europe and Russian countries, hence Wolf's involvement. It makes sense, since the Grendel can use the same bolt as the 7.62x39 (there are bolt depth differences in ARs, but that's a side note) and just requires a straighter magazine and different barrel.

Notice how 7.62x39 AK47 magazines have a lot of curve to them, like a banana? That's because the case body has a lot of taper, and that's what makes it a less desirable cartridge in an AR15. The AR magazine well is fairly straight, so the top ~10 rounds or so of the mag can't be as curved as it should be. There are (or have been) AR15 lowers made specifically for this cartridge that use a more curved magazine, but those lowers are non-standard and don't fit other cartridges as well.

Something else to know - once you get on the same page of looking at cartridges of the same frame size, you can change calibers by swapping barrels, but it's not something you would do on a regular basis. Instead, you'd swap complete uppers, along with any necessary magazine changes. You'll eventually figure out though that while just swapping uppers sounds reasonable, it's better to just add another lower and have two complete rifles. A lower set up for long range is not usually ideal for a short range knock-around blaster anyway.

On twist rate - for the 6.5 Creedmoor, 1:8 is generally the accepted twist rate, although going a little faster twist like 1:7 or 1:7.5 etc is fine. Twist rate requirements are based on bullet length, not weight, so you can't really compare twist rate values across different calibers. Longer bullets need faster twist (1:8 is faster twist than 1:10, etc.)

Hope that helps. Now that we're getting this stuff cleared up, could you tell us about your background, and why the sudden interest in this stuff? Thanks!

Thanks for the reply! Yeah things are definitely starting to clear up.

Pretty much my background has always been tied to guns. My dad is a collector, and whole family is heavily into them. I’ve been hunting, shooting, ect since I was about 14. So when it comes to a small few bolt rifles, AR15s, 22s, and shotguns I am super proficient and pretty knowledgeable. About 4 years ago is when I started getting into handguns, my first one being a Glock 19 and is still my favorite. I am really into the guns I have and research them relentlessly, but when it comes to stuff I’m unfamiliar with, I know nothing. Something I need to change.
I was born and raised in Commiefornia, mostly the suburbs, acre parcels, and by the time I was 18 I was living in apartments, going to school, then moving into a condo for a few years, then a quarter acre size house/parcel the last few years. So any time I ever wanted to go shooting, I’d have to drive away from my house and go to an indoor shooting range or take a trip to some blm land in the national parks. So I’ve always shot within 200-300 yards max, mainly plinking around within 100 yards. There just isn’t enough land to shoot farther and I never really cared to try and find something more open. The only times I ever really found myself in an open area was while hunting pretty far away from where I lived, and that’s not the most ideal time to go off making noise and scaring everything away.

About 4 months ago my entire family decided enough is enough and decided to move out of California. I was the last one left here and during a visit to Tennessee, where my parents ended up, my dad and I went out to the back yard with some guns and allll the way at the end of his property, about 800-900 yards right before a lake was a big tree and he had out his Remington Magnum 7mm. So I took the atv and set up a swinging gong right next to the tree. He worked his magic on the scope like it was nothing and I took a few shots at it, hitting it on the 6th or 7th shot. The whole experience of pulling the trigger, nearly a 1 second delay and then GONGggggg... which I was able to hear really well as it was amplified through the active ear pro I was wearing, I was instantly hooked. I wanted to know how my dad knew how much to adjust the scope, all the little variables he jotted down on his phone to get it pretty darn close, and the fact that I wasn’t able to hit it again just got me super motivated to want to learn how to shoot long range. I shot about 10 more rounds at it and kept flinging up dust all around the gong after that lucky hit, and then my dad nailed it 3 times in a row only missing the first shot. I didn’t want to waste his ammo fishing for another lucky hit. But something clicked when I did hit it, like when you discover a hobby for the first time.
So since then, I’ve bought my own house in Tennessee, and have been setting up a little shooting area and then some long range targets along the side of my property and having a blast with my AR15. My property is kinda in the backwoods but there is almost a mile and a half stretch line of sight in one direction that I am fully intent on using up. I’m going to really have to treck to get a target up at the mile mark since there is a little lake and wetland area making up about half of the last part. And I wonder if shooting over water is going to affected bullet’s flight characteristics..Hmm. Just thought of that.

I’ve been going through the TiborasaurusRex Sniper 101 Series. And I can tell it going to take a loooong time to get where I want to be. So that’s why I’m looking into getting a new rifle. And as much as I appreciate bolt guns for hunting, I am definitely a Semi Auto guy. That may change when I start shooting past 1200 yards but for now a SA gun is what I want. I know there are a few exotics like NEMO Arms that make some great AR style rifles. I’ve been eyeballing the Nemo Omen Watchman In 300WM and RockRivers BT-6 .338 lapua. But seeing as how I am already going to be throwing a painful amount of money on a viper razor HD or Leupold Mark 5, that’s going to have to wait. I also want an Acog (lmao) Not to mention I am nowhere near the skill level to actually utilize what those rifles can do. Yet.

lol... sorry for the massive reply lol But that’s where I’m at.

 

[308pirate]

So this is what all the panic buying has brought us. People without a clue who want all the answers right fucking now........

 

[MarshallDodge]

I am more of a 6mm guy but I will lend you some of my experience. 15 years ago I had a DPMS LR-308 with the heavy barrel. It shot fine but was big and heavy for what it did. With 77 grain bullets I can do the same thing in a standard AR, just without the energy but for my needs I don't need it, and it costs way less to shoot.

A few years ago I picked up a used 20" FN 308 with a 1:12 twist barrel that will shoot sub MOA, and will hit 12" steel at 1000 yards as long as I get the wind read right. Load is 155 Berger Target with 8208. I've never tried 175 grain bullets in it, and probably won't because I use my 6x47L for the longer stuff.

You don't need anything special to get to 1000 yards. What you need is something you will enjoy shooting for thousands of rounds so you get proficient.

 

[twentyeggs]

.

You don't need anything special to get to 1000 yards. What you need is something you will enjoy shooting for thousands of rounds so you get proficient.

This! Is exactly what I am thinking with the two different setups. What I really want to do is build a large chamber/M5 chambered in 7.62x51/.308 and shoot the hell out of that, learning the basics, learning the techniques, knowledge, and refining my skill.

THEN, when I start getting proficient and want to shoot longer ranges without having to twist the hell out of my scope, that will deal with wind drift a little better, and making my job of 800-1500 yards a more doable, I will have a platform ready to turn into a 6.5 Creedmoor.

So my issue right now is compatibility. I love Aero Precision, and already have an upper and lower by them ready for the build. So I am just trying to understand the different types of fitment.
I just want a high quality/high accuracy barrel, BCG, that will fit an Aero threaded upper/lower.

like does DPMS work essentially like mil spec? So long as it says DPMS it should work together? What I understand is, the M5/.308 and it’s parts are basically built by a few different companies, like DPMS, and there is no standard for fitment like the AR15. So if your going to build one, you’ve gotta pick a company and base the platform around it’s somewhat proprietary parts. Did I get that right?

So if that is the case, I’m fine with doing that. I have the Aero Upper and Lower, I’ll go with the Aero Lower Part Kit, a nice drop in trigger of course, Aero Charging Handle unless I can find a nice high profile ambi CH for a good deal.


So here is where I start to get into unknown waters.
I don’t particularly like the Aero Handguards, especially don’t like the big round enhanced versions for their enhanced upper. And I want a nicer, more accurate barrel than what Aero provides. And because I want a different barrel, I also want a really nice high quality BCG that is made or known to match up with that barrel.
(Since the barrel, BCG, and trigger are the main components that influence accuracy, I’m willing to afford around $1k for these parts.)

What do I look for, how do I know if the barrel is compatible for the Aero M5 upper? Are there compatibility issues with the barrels or do they all fit DPMS/Armalite platforms? What causes the difference if there is any?
-I’ve noticed that the barrels all specify a thread pitch such as 5/8thx24 which will fit the DPMS specs Aero uppers are made to. Is that is? Or is there another area of measurement I need to consider?


The BCG, are there compatibility issues with this also depending on the AR-10/LR-10 platform?

the hand guard should be easy to find, as I believe it just needs to be a high profile that matches the Aeros high profile upper.

Then there is buffer spring. I assume as long as I also go with Aeros BS I should be good.

 

[twentyeggs]

So this is what all the panic buying has brought us. People without a clue who want all the answers right fucking now........

Are you smoking crack?

I didn’t even go out and buy ammo since all this COVID junk happened. How is wanting to slowly build a 6.5CM, over the course of several years, panic buying. I’ve mentioned several times now I already own an AR15 among other guns which are far more suited for personal defense Vs a heavy 24”+ bench gun... like wtf?

And what’s your issue with people who “don’t have a clue,” wanting to learn quickly? Is there a rule to how fast we are allowed to learn things? Is it one answer to one question every 24 hours? Or am I restricted to one answer every 30 days? What is the rate of knowledge, that you privilege someone like me, when it comes to learning about building a .308 rifle? Am I asking too many questions and breaking the rules?

 

[Coffee_and_Pipes]

Unless you really want the experience of putting something together yourself, I’m going to second what @nn8734 said and recommend an LMT MWS. As I was reading your posts, that’s what kept coming to mind for me. The benefit of picking up an MWS is that you get a system where all of the parts have been proven to place nicely together. If you were planning on buying 2 uppers that means 2 sets of optics. With an MWS, you would save money by only needing one scope and mount. You might look through the LMT MWS thread that’s pinned toward the top of the semi-auto rifles page. I think the thread goes back about 8 years, so there’s plenty of material to skim through.

edited to add: if you want some of the experience of assembling your rifle, you might consider buying a stripped MWS lower. Then, you get to assemble something, but if you’re sticking to all LMT parts (aside from maybe the stock or trigger) you’ll know you have parts that have been tested as a group. The only downside to that is that certain parts might be tougher to find at times. For instance, I’m looking for a NIB bolt carrier group for the MWS I’m assembling, and I haven’t found any at the moment. They’ll be available later, but that means that I can’t shoot this rifle for the time being.

 

[MK20]

Don’t worry. Just keep asking questions and you will get answers. Make your questions a little more pointed and less of a life story though and you will get more answers.

 

[DavidAR10]

If you're going with an AR build:
A) The bolt gyz have proven that Proof Research knows how to make barrels that win. So, I trusted the notion
that PR also knows how to make std & lrg frame AR barrels and grabbed the 24" CF 6.5CM.
What The Pros Use
What I bought PR10 #100059
I don't believe PR knows how to make a bad barrel.

B) Schuyler Arms is where I purchased my AP M5E1 build kits. Between Thanksgiving and Christmas 2018, SA was selling the kits for $300 ea, non-blems.
I loved the quality of my first kit so much I grabbed more for different manufacturer's pipe builds.
Cut & Paste of a few SA Sales Receipts during those crazy Holiday Sales from www.schuylerarmsco.com
Item Details

Product ID	Item	Qty​	Price​
APRH100386C	M5 .308 Lower Parts Kit, Minus FCG/Pistol Grip	2	$60.00
1775298	Aero Preclusion M5E1 Builder Set w/ 15" M-LOK Handguard	1	$300.00
APRH308186C	.308 / 7.62 Bolt Carrier Group, Complete - Black Nitride	1	$150.00
Subtotal:​	$510.00​
Shipping:​	$17.00​
Tax:​	$0.00​
Total Amount:​	$527.00​

Item Details

Product ID	Item	Qty​	Price​
803894	Aero Precision .308 / 7.62 Bolt Carrier Group, Complete - Black Nitride	1	$145.00
775083	M5 .308 Lower Parts Kit, Minus FCG/Pistol Grip	1	$30.00
APPG308556	M5E1 Complete Upper, 22" 6.5 Creedmoor SS Rifle Barrel, EM-15 HG - Anodized Black	1	$375.00
Subtotal:​	$550.00​
Shipping:​	$10.00​
Tax:​	$0.00​
Total Amount:​	$560.00​

Item Details

Product ID	Item	Qty​	Price​
1823027	VG6 Lambda PRS30	2	$140.00
Subtotal:​	$140.00​
Shipping:​	$8.75​
Tax:​	$0.00​
Total Amount:​	$148.75​

I replaced all four of the AP bolts in each AP BCG with a JP Rifles High Pressure bolt kit:

JPBC-EB308HP

JP High Pressure EnhancedBolt™ Assembly Completion GroupCaliber: .308 Win. Finish: Black DLC

$213.95​

I have four 6.5CM ARs built on AP M5E1 frames: two BA barrels 22" & 24", one PR CF 24" and one DRACOS SJ 22". I need to build my last kit and grab another PR barrel.
I wish PR built barrels with ARMALITE barrel extensions. Well hell, there AIN'T nothing wrong with a Krieger or Craddock Precision pipe.

Best to you.

 

[Yondering]

Don’t worry. Just keep asking questions and you will get answers. Make your questions a little more pointed and less of a life story though and you will get more answers.

Nah he's fine. The life story thing as you referred to it was a direct answer to my question about his background. That helps all of us know how to help him better.

 

[twentyeggs]

If you're going with an AR build:
A) The bolt gyz have proven that Proof Research knows how to make barrels that win. So, I trusted the notion
that PR also knows how to make std & lrg frame AR barrels and grabbed the 24" CF 6.5CM.
What The Pros Use
What I bought PR10 #100059
I don't believe PR knows how to make a bad barrel.

B) Schuyler Arms is where I purchased my AP M5E1 build kits. Between Thanksgiving and Christmas 2018, SA was selling the kits for $300 ea, non-blems.
I loved the quality of my first kit so much I grabbed more for different manufacturer's pipe builds.
Cut & Paste of a few SA Sales Receipts during those crazy Holiday Sales from www.schuylerarmsco.com
Item Details

Product ID	Item	Qty​	Price​
APRH100386C	M5 .308 Lower Parts Kit, Minus FCG/Pistol Grip	2	$60.00
1775298	Aero Preclusion M5E1 Builder Set w/ 15" M-LOK Handguard	1	$300.00
APRH308186C	.308 / 7.62 Bolt Carrier Group, Complete - Black Nitride	1	$150.00
Subtotal:​	$510.00​
Shipping:​	$17.00​
Tax:​	$0.00​
Total Amount:​	$527.00​

Item Details

Product ID	Item	Qty​	Price​
803894	Aero Precision .308 / 7.62 Bolt Carrier Group, Complete - Black Nitride	1	$145.00
775083	M5 .308 Lower Parts Kit, Minus FCG/Pistol Grip	1	$30.00
APPG308556	M5E1 Complete Upper, 22" 6.5 Creedmoor SS Rifle Barrel, EM-15 HG - Anodized Black	1	$375.00
Subtotal:​	$550.00​
Shipping:​	$10.00​
Tax:​	$0.00​
Total Amount:​	$560.00​

Item Details

Product ID	Item	Qty​	Price​
1823027	VG6 Lambda PRS30	2	$140.00
Subtotal:​	$140.00​
Shipping:​	$8.75​
Tax:​	$0.00​
Total Amount:​	$148.75​

I replaced all four of the AP bolts in each AP BCG with a JP Rifles High Pressure bolt kit:

JPBC-EB308HP

JP High Pressure EnhancedBolt™ Assembly Completion GroupCaliber: .308 Win. Finish: Black DLC

$213.95​

I have four 6.5CM ARs built on AP M5E1 frames: two BA barrels 22" & 24", one PR CF 24" and one DRACOS SJ 22". I need to build my last kit and grab another PR barrel.
I wish PR built barrels with ARMALITE barrel extensions. Well hell, there AIN'T nothing wrong with a Krieger or Craddock Precision pipe.

Best to you.

Wow! You got a complete upper with actual name brands for 375... I would do that right now just to have something now, and do my custom build later! lol

 

[drewthebrave]

Wow! You got a complete upper with actual name brands for 375... I would do that right now just to have something now, and do my custom build later! lol

Those look like pre-pandemic prices to me. I bought most of my parts from Schuyler Arms Co during their Black Friday sale and completed my 6.5 Creedmoor build for about $1100 before optics (including a $400 Craddock Precision barrel). These days, prices are a bit higher, and most good deals sell out quickly. If you're patient, you can piece together a build as you find parts in stock, which will give you time to research parts you're on the fence about.

My advice: if you want a Creedmoor, don't waste your time with .308. The improved aerodynamics are going to increase your first shot hit probability at long range, and quality ammo is comparable in cost between the two calibers. Luckily, the only thing you need to change is the barrel (assuming you have a high pressure bolt), so you can gather all the other parts and wait to decide on the barrel until you are 100% sure what caliber you want.

 

[Yondering]

My advice: if you want a Creedmoor, don't waste your time with .308. The improved aerodynamics are going to increase your first shot hit probability at long range, and quality ammo is comparable in cost between the two calibers.

This. There's not much point in building it as a 308 first if you're planning on turning it into a Creedmoor later; that doesn't make a whole lot of sense.

 

[Im2bent]

I am in the process of converting a .308 to 6.5Cm as we speak. As Yondering said don't waste your money on a 308 and then turn it into a CM. I did not know squat about the AR platform being capable of running 6.5CM did not know what 6.5CM was when I put my DPMS style AR together or I would have gone the route I am now following. I am going with a 24" barrel with 1:8 twist. The length of the barrel does not play into the twist. Bullet weights do(basically). For target shooting with the CM you dont need super heavy bullets I believe most use a 140gn ELD and 1:8 twist is the current flavor. As far as the gas system the CM creates a lot more pressure than a .308. You want the longest gas system you can get. Most barrels will only go rifle length max some manufacturers are making longer gas systems such as rifle +2 to tame the pressure so you dont beat your gun and brass to death. Some barrel makers with the rifle length gas systems are going with a smaller port in the barrel to control/reduce pressure. You will want an adjustable gas block to adjust the pressures your BCG is seeing so your ar runs smoothly and functions properly. The 308 has more punch at shorter ranges but once you get past 1000 yards the CM really shines ballistically. You are doing the right thing asking questions and learning before spending money going down the wrong path. Oh you also need what is called a high pressure bolt. This is a bolt with a smaller diameter firing pin and smaller hole for said firing pin. This prevents your primers from being blown out by the higher pressures of the CM. Other than that the rest of the gun is the same as a 308 AR. Good luck with your build.

 

[DavidAR10]

Those look like pre-pandemic prices to me. I bought most of my parts from Schuyler Arms Co during their Black Friday sale and completed my 6.5 Creedmoor build for about $1100 before optics (including a $400 Craddock Precision barrel).

Roger That. I stated the times of purchases in my reply: Thanksgiving - Christmas 2018

www.schuylerarmsco.com is a great company to deal with.