AR10 (DPMS pattern)

[itchyTF]

What would you suggest? I bought an AR10 (LR308) upper and 80% lower from AMT and can't decide what cartridge to set it up for. I want to keep it in 6mm. In bolt guns I have 6mm-250, 6x47L and 243AI. So, what would the community suggest for a cartridge for this thing (and why)?

 

[mac86951]

What would you suggest? I bought an AR10 (LR308) upper and 80% lower from AMT and can't decide what cartridge to set it up for. I want to keep it in 6mm. In bolt guns I have 6mm-250, 6x47L and 243AI. So, what would the community suggest for a cartridge for this thing (and why)?

Well, 308 is great all around. What do you want to do with it?

 

[itchyTF]

I gave my 30 cal rifles and components to my son. I decided to max out on 6mm recoil. I was afraid someone was going to ask what I want to do with it. Good question! I don't do competition anymore and the only "hunting" I've done in the past number of years is groundhogs (PA) and prairie dogs. Haven't seen too many hogs around here (E TN) and PD's are about 1,300 miles away. I guess at this point the build is more for a project than anything else. I know, sounds lame.

 

[270Wby]

I would go with whichever provides access to the cheapest brass. This system isn’t gentle on brass by any means. Mine is a 308, rifle length adjustable gas system, which I built the same way you are. It beats brass up pretty well. I can’t speak for how many reloads you can expect as I’m only on the 2nd go around for the cases I’ve ran through it. But, my AR15 brass is averaging 3 reloads on commercial cases and 4-5 on military 5.56 cases.

 

[itchyTF]

I've got 3 AR15's, one is .223 and the other two are .20 Practical. All my brass is military and they don't look beat up at all. Don't know what larger cases would look like through an AR10.

 

[half]

I’ve got a large frame .243, and I love. I found a load that shoots well with new unprocessed brass. I use it mostly to hunt coyotes, so if I loose a few pieces of brass over the winter, it’s not a big deal. Just my .02

 

[slm9s]

Plain Jane 2 4 3

 

[mac86951]

If you want something different; but 6mm and slightly longer barrel life than 243; I'd go 6XC, but wow id hate to lose brass in the weeds. 243 would be fantastic as well. I've heard of a few that have troubles with gas system timing, personally, I'd look at a rifle+2" gas system for that. It would mean a custom barrel most likely (if that's what you're planning no biggie). White Oak will make you a custom gas tube. Last I recall they were $30? Nickels n dimes compared to the brass savings from case head swipe if you want factory ammo.

-Mac

 

[Oso]

Food for thought - I built my first upper in 308 under the "If SHTF there will be ammo" knowing that this round was utilitarian and I could bang away with high round count. My 2nd upper for precision shooting is 6.5 Creedmoor. For me I have bolt guns in 6mm and 50 rounds is a good shooting session over a couple of hours. I have found that with an AR15 OR AR10 most people, including seasoned, disciplined shooters, throw out their normal consideration and don't think about rate of fire or barrel temperature nearly as much. Suddenly, 100 rounds in an hour seems fine with a gas gun and 20 round magazine.

How much do you plan to shoot this rifle?

Keep in mind that all 6mm intermediary cartridges (6mm Creedmoor, 243 Winchester, 6mm Remington, etc) all suffer from limited barrel life ... 1,500 precision rounds and a bit more for MOA. Generalization - the barrel life is lower in an AR platform as a result of shooting habits... higher round counts per session and more rapid pace of shooting both translate into more heat/hotter barrel ---> shorter barrel life. How often do you want to replace the barrel?

A .308 Win means you have a barrel life approaching 5,000 rounds. If you don't want .308 then give the 6.5 Creedmoor a hard look with better design for feeding in gas gun, and barrel life that is 1.5-2x that of 6mm cartridge.

Last thought - the recoil on a AR15/AR10 is always less then a bolt rifle. Include an adjustable gas block to reduce amount of excess backwards force / recoil.

 

[velocette]

Oso do speak the truth.

 

[urbanrifleman]

Whichever 6mm you choose I suggest you start with a small gas hole. Probably no bigger than 80 thou.

 

[itchyTF]

What size gas hole would be good with a 6.5 Creed?

 

[duke260]

Look up Accuracy Systems out of Colorado. Ask to speak with Carl. He built my upper with my 6xc reamer, and did a great job. It shoots the 107 mk great. My grandson shot this 3 shot group at 500 meters.

 

[msalm]

Whichever 6mm you choose I suggest you start with a small gas hole. Probably no bigger than 80 thou.

Start at .060”.... test fire and go up from there or use an adjustable gb.

I’ve built many calibers in the 10 platform from 6x47 Lapua to 358 Win and the smaller bores definitely have a higher port pressure that are easy to over gas.

As for caliber, 6 Creed would be a pretty good choice as brass and ammo is common and it does fit the platform well.

 

[itchyTF]

Anybody have any experience with X-Caliber barrels?

 

[Txhillbilly]

I have a couple X-caliber barrels on bolt actions. They shoot rather well.

 

[Loudenboomer]

I'm building DPMS AR-10 in 7-08. I have most of the parts. Waiting on the SA adjustable gas block and the X-Caliber barrel. Ordered a 22" HBAR with +2" gas length. I have more than a lifetimes supply of JLK 180 vld bullets so I went with 1-8 twist. I think I'll try Staball 6.5.

 

[Pinetreebbs]

I'm building DPMS AR-10 in 7-08. I have most of the parts. Waiting on the SA adjustable gas block and the X-Caliber barrel. Ordered a 22" HBAR with +2" gas length. I have more than a lifetimes supply of JLK 180 vld bullets so I went with 1-8 twist. I think I'll try Staball 6.5.

I have a PSA AR-10 in 7mm-08, the thing is a tack driver with Varget and Speer 115 grain HPs