AR10 Build

[Cerisecons]

I am putting together my 3rd Aero Precision M5 build, and I have built a 20" 308 and a 22" 6.5 Creedmoor, I am looking for ideas for the next caliber. I was considering a 260 Remington but after some research into gas issues I think maybe something different. I also considered 7mm-08 as it appears to be a good in-between choice.
I mostly punch paper and ring steel, so hunting is not an aspect I'm considering for this rifle, and I also reload for all my toys, so an odd caliber doesn't bother me, if it has other interesting features and benefits.

 

[6AYoteHunter]

6 creedmoor

 

[G-Dog]

Shameless projection of my personal fantasies: 22 Creedmoor ?

 

[Black max]

I am putting together my 3rd Aero Precision M5 build, and I have built a 20" 308 and a 22" 6.5 Creedmoor, I am looking for ideas for the next caliber. I was considering a 260 Remington but after some research into gas issues I think maybe something different. I also considered 7mm-08 as it appears to be a good in-between choice.
I mostly punch paper and ring steel, so hunting is not an aspect I'm considering for this rifle, and I also reload for all my toys, so an odd caliber doesn't bother me, if it has other interesting features and benefits.

What do you mean by "gas issues" with a 260? You might have a seating longer bullets issue but gas will not be a problem.

 

[Cerisecons]

Thank you for the reply. I have read several forums and possibly a thread on SH, but I recall it was noted to get a +2 on the rifle gas tube, and there were some other gas items noted, that the 260 was designed for BA, and also recall your note about COL for the mags. That actually might be the best consideration, as mag length certainly could become an issue with the longer projectiles we now have.
I am not opposed to the 260R, as I have dies and brass for it, but because of the noted COL issue, may do a bolt gun for it instead.

 

[Cerisecons]

6 Creedmoor... that might be something I need to research ...

 

[Black max]

6 Creedmoor... that might be something I need to research ...

You will need an extended gas system for it as well.

 

[Cerisecons]

You will need an extended gas system for it as well.

OK Good to know, my 22" BA 6.5 is a little finicky with lighter charges as well.
Thank you

 

[Cerisecons]

Shameless projection of my personal fantasies: 22 Creedmoor ?

Would that be like a 224 Valkarie on steroids? LOL

 

[G-Dog]

Would that be like a 224 Valkarie on steroids? LOL

Basically! The rumored speeds put it on par with a laser. I don’t have one, but I want one (hence my projecting a bit), and when funds permit will build one.

 

[Cerisecons]

Any thoughts on the 7mm-08?
I'm concerned of barrel erosion on the 6mm Creedmoor from different articles I have read, and didn't see a lot of information on the 7mm-08, either erosion or positive / negative...

 

[7mmFanBoy]

use 18" 7mm-08 ar10 generally shoot 139gr some 150g. My chamber likes 3031 / faster burning powders. I can't use 160g higer bc bullets without dropping alot of pressure dealing OAL. I don't think my throat has moved 1k+ rounds my velocity is around 2600fps ( slower barrel 6 groove x-caliber). Postives : use LC brass , surplus powders, cheap bullets, out at range same longer barrel 24" 308 .

 

[silentsquirter]

It's not an AR10, but I really enjoy my 16.5" 7mm-08 BA. Currently pushing 150 grain ELD-x's @2570. With that being said, it is my go to whitetail deer rifle. If a 7mm-08 is in between a .308 and 6.5 CM in terms of ballistics, wouldn't it be advantageous to try something different? I'm with @G-Dog , I'd go with a 22 creedmoor.

 

[Cerisecons]

Basically! The rumored speeds put it on par with a laser. I don’t have one, but I want one (hence my projecting a bit), and when funds permit will build one.

Good Morning,
So I just looked up 22 Creedmoor as I saw an article on it, and I honestly thought it was a Joke until reading the article...
It definitely is interesting, but I need more research and to see if it can work in a Semi, seems to be in BA from the article I read...

 

[Gatorshark]

Did anyone already mention 6 creed?
I think the 6 creedmoor pretty much nullifies the 243 barrel offerings for the AR10 ish rifle.

 

[bunsen27]

8.6 Blackout should be an option later this year. I'm anticipating Hornady to officially release it at NRA show in April.

 

[Cerisecons]

Good morning, well I went with the 260 Remington. I found a Wilson Combat 24" match barrel. I went with a Superlative Arms Adj gas block by suggestion. Also just acquired some once fired Lapua and Remington brass, now to load up some and get them fire formed to the new barrel.

Thanks again for the suggestions.

 

[G-Dog]

Good morning, well I went with the 260 Remington. I found a Wilson Combat 24" match barrel. I went with a Superlative Arms Adj gas block by suggestion. Also just acquired some once fired Lapua and Remington brass, now to load up some and get them fire formed to the new barrel.

Thanks again for the suggestions.

Thanks for letting us know the final direction. Keep us posted with a range report when the time comes!

 

[Mauserj]

I just picked up a Noreen BN 36 in 300 Win Mag and 30-06. Have not shot them yet but will let you know.
Scoped them with long range Burris 5x20x50mm.

 

[Gatorshark]

Good morning, well I went with the 260 Remington. I found a Wilson Combat 24" match barrel. I went with a Superlative Arms Adj gas block by suggestion. Also just acquired some once fired Lapua and Remington brass, now to load up some and get them fire formed to the new barrel.

Thanks again for the suggestions.

Of course you know not to mix the brass when loading. I bet you have better consistency from the lapua brass.

Sounds like a great build.

 

[Cerisecons]

Of course you know not to mix the brass when loading. I bet you have better consistency from the lapua brass.

Sounds like a great build.

Yes, I separate and load per head stamp, even by weight if the brass is found to be too far out of spec compared to the others. First loads will be mid level just to fire form, the the o.c.d can take over... ?
I'm looking forward to the Lapua, I've looked into it for the Creedmoor, but my results with Starline there have been satisfactory.

 

[Cerisecons]

Thanks for letting us know the final direction. Keep us posted with a range report when the time comes!

I definitely will continue with followup here, as I see more threads on ar10 builds since starting this thread.
Oh I also upgraded the 308 barrel in another AR-10 to a match BA bull barrel, so we'll see how that goes as well. The old barrel was shooting OK, but as I recall was not quite the same quality... Now to hopefully punch little holes in paper next weekend...

 

[padom]

Yes, I separate and load per head stamp, even by weight if the brass is found to be too far out of spec compared to the others. First loads will be mid level just to fire form, the the o.c.d can take over... ?
I'm looking forward to the Lapua, I've looked into it for the Creedmoor, but my results with Starline there have been satisfactory.

Unless that barrel was chambered for a 260 gasser specifically, you'll run into COAL issues. You'll want to make sure you have the longest COAL mags possible to start if handloading (KAC, Larue, ASC SS). You wont be able to get anywhere close to the lands and feed from a mag if it wasnt chambered with a 260 reamer designed specifically for gassers.

This is the reason the 6.5cm is much much more popular in a gasser. You can get all the way to the lands in mag length with room to spare and be able to chase them. That's why a lot of us that have been building and shooter large frame gassers moved away from 260 to 6.5cm a long time ago.

Now, before the dedicated fan boys come and start flaming. Dont misinterpret what I said. Im not saying it wont shoot, or wont be accurate. I'm not saying that at all. You will just be limited on your lengths and what bullets you can load with if it's got a normal 260 chamber. That's all. You'll have to work with that. Possibly jump a large distance. Especially with pointy, long high BC bullets like 140 Hybrids, 130 Hybrids etc. and still feed out of a mag.

 

[Cerisecons]

Unless that barrel was chambered for a 260 gasser specifically, you'll run into COAL issues. You'll want to make sure you have the longest COAL mags possible to start if handloading (KAC, Larue, ASC SS). You wont be able to get anywhere close to the lands and feed from a mag if it wasnt chambered with a 260 reamer designed specifically for gassers.

This is the reason the 6.5cm is much much more popular in a gasser. You can get all the way to the lands in mag length with room to spare and be able to chase them. That's why a lot of us that have been building and shooter large frame gassers moved away from 260 to 6.5cm a long time ago.

Now, before the dedicated fan boys come and start flaming. Dont misinterpret what I said. Im not saying it wont shoot, or wont be accurate. I'm not saying that at all. You will just be limited on your lengths and what bullets you can load with if it's got a normal 260 chamber. That's all. You'll have to work with that. Possibly jump a large distance. Especially with pointy, long high BC bullets like 140 Hybrids, 130 Hybrids etc. and still feed out of a mag.

Good morning, that is one of the reasons I didn't jump into the 260 early and was looking at other calibers, but the others I looked at besides the 308 and 6.5 CM I have on my other AR-10s didn't hit my "build it" sence. I plan on lots of tests with the COAL etc and will also single load to verify loads. I have the appropriate gauges and we will see how it plays out.

 

[padom]

Good morning, that is one of the reasons I didn't jump into the 260 early and was looking at other calibers, but the others I looked at besides the 308 and 6.5 CM I have on my other AR-10s didn't hit my "build it" sence. I plan on lots of tests with the COAL etc and will also single load to verify loads. I have the appropriate gauges and we will see how it plays out.

My experience with reamers not specifically made for 260 gassers I need 2.92 or so to get to the lands with 140 Hybrids, 2.90 for 130 Hybrids, etc. Max in your longest COAL mags will be 2.71 in KAC Or Larue... so just test your distance to the lands with your overall length gauge with the bullets you plan to reload with to see what your distance is. You will know right away. Good luck

 

[Cerisecons]

My experience with reamers not specifically made for 260 gassers I need 2.92 or so to get to the lands with 140 Hybrids, 2.90 for 130 Hybrids, etc. Max in your longest COAL mags will be 2.71 in KAC Or Larue... so just test your distance to the lands with your overall length gauge with the bullets you plan to reload with to see what your distance is. You will know right away. Good luck

Good evening,
Well my quick COAL for 143g ELD X is 2.92...123g H ELDM is 2.86.
I have a few others that fit below the 2.82 max COAL for the magazine.

My fire form session will be with some 144g Fmj BT bulk that gives me 2.82, these I can fit into my Pmag for the first go. I may do a few of the 143s and single load to see how they group, or not...
I'll report later with the first results, knowing that this first set is a rough test.

 

[padom]

Good evening,
Well my quick COAL for 143g ELD X is 2.92...123g H ELDM is 2.86.
I have a few others that fit below the 2.82 max COAL for the magazine.

My fire form session will be with some 144g Fmj BT bulk that gives me 2.82, these I can fit into my Pmag for the first go. I may do a few of the 143s and single load to see how they group, or not...
I'll report later with the first results, knowing that this first set is a rough test.

Yep. That's why you dont see lots of 260 gassers. Ditch those pmags and get some ASC SS or KAC mags. They do up to 2.871.

 

[Cerisecons]

Yep. That's why you dont see lots of 260 gassers. Ditch those pmags and get some ASC SS or KAC mags. They do up to 2.871.

Absolutely, I have my LGS on that, but until it arrives, this PMag will work for the test...