Hi All,
New guy here from Maine. Glad to be here! I'm looking for guidance in selecting an AR10 in .308 for suppressed use, so am considering my first AR10 specifically for this purpose. Uses will include range, defense, varminting. Ideally will be piston (minimize backwash into rifle and face), adjustable gas block, MOA or better accuracy with the right ammo, mechanical durability, good customer support  and availability of critical parts. At the top of the current considerations is the LMT MARS H piston which checks all the boxes (have an LMT LM8 MWS DI rifle which is fantastic-routinely sub-MOA but not a great suppressor host), but have questions about some on line concerns raised about current QC, fit/finish, and availability of parts with LMT's military contracts.  I do get that posts are often biased toward negatives.  Would appreciate any first hand experience with this system, especially running suppressed. Of course, other systems to consider with pros/cons are also welcome. Hope this in the right forum heading. Thanks  so much!

Rise Armament 1121xr 308
guaranteed sub-1 MOA

More like a 1/4 moa or less

Mine love's pmc match 168gr
or federal gold metal 175 gr.

Call them and they will tell you what ammo works best in them.

Don't know about all your other requirements.

I would love to see some .25” or less 5+ round groups.

16” barrel, rifle length gas system, adjustable gas block, armalite/vltor A5 length buffer tube (with H3 buffer).

Use Aero M5 receiver set as its semi-monolithic. Combine with Criterion 16” barrel. You’ll spend less then any factory rifle, have a softer recoil impulse then most factory rifles, and accuracy will be equal to if not better.

I just went this exact route but with a 16" Noveske switchblock barrel. Basically building an Noveske N6 (noveske parts) except with Aero upper and lower. It's a significant cost savings over a factory N6.

might want to consider a 14.5" or 13.9" barrel, with pinned & welded suppressor-mount muzzle device to get that ATF-legal 16", so that your overall length with suppressor is slightly shorter than with a 16" barrel.  just food for thought.

Thanks for the replies so far. No experience in building, so leaning more toward factory build

If you're in the price range of the LMT in 308, you should also research the Larue OBR or PredatOBR. https://www.larue.com/category/rifles/predatobr-7-62/

They're both combat proven and durable enough for specops, with the ability to keep on cycling even when filthy. The main difference is that the Larue is inherently more accurate than the LMT, which may come in handy if you get a chance to stretch it out.


The LMT is still a very good choice though, just wanted to highlight a direct competitor that might be interesting for your use case.

Yes, please...

I doubt this was accomplished with a statistically significant amount of rounds

Thanks for this option. While the LaRue has the adjustable gas block, it looks to be DI rather than piston and is $1K higher priced than the LMT. If I were to give up the piston for DI and kick in another $1K, probably would also look into a JP LRP 07... but is the price difference gaining much or anything at all over the LMT?

The main difference will be the long distance accuracy of the Larue over the LMT. If you don't have access to ranges beyond 500 yards, the accuracy difference probably isn't enough to justify the extra cost. If you want to shoot longer ranges though, the Larue will take you to happy places.

Got it-thanks! Not a lot of wide open spaces here on the east coast. The range I belong to goes to 100 yds, while on our property, I can run out to 500 yds, but that's about as far as my reality will permit.

Cmmg mk3 dissent

I'm always for buying new guns, but why not pickup a piston barrel and BCG from LMT?

Brilliant and staring me right in the face- of course! Take advantage of the modular system. I'll check in with LMT to see if the piston barrel and BCG is available for and compatible with my rifle. If so, totally makes sense. If not, well, looks like the new gun route will be the path of least resistance. Thanks!!! This could save a bundle!!!

You’re best off getting a DIbgun because of availability, if you’re willing to spend LMT money you could get a noveske n6 switchblock which would be better suppressed than other DI guns.

Waxster60,

Being a beginner to the AR-10 and I'm assuming you don't have a lot of expeirience with suppressors, I suggest you start your career with a commercialiy built 20" or 18" AR-10. Commercially has a wonderful benifit called a warranty.

Either an 18 or 20" barrel with a rifle length gas tube or a +2 rifle length gas tube will be the easiest for you to tune to your liking. Being a suppressor host, you will want an adjustable gas block on the upper. 308 gas guns may be a little over gassed. At this point in your gas gun career, shorter gas systems can give anyone troubles. Check out the troubleshooting section of this forum, you will see plenty of threads about short gas systems.

I also suggest that you don't go with a physically light AR, a 308 gas gun can have a sharp recoil. An AR does a bunch of moving when you crack a primer. the difference between the recoil cycle of a bolt action rifle and a gas gun is night and day. Basically, a gas gun is much harder to shoot than a bolt gun. The gas gun jumps around a bunch. I suggest you check out the "How to shoot a gas gun" training available. It took a gob of practice for me to finally watch my round impact my target through the scope. Being able to get to the point of watching my rounds impact my target, showed me how accurate a regular old DPMS GII can be.

I will finally suggest that you start with a rifle that doesn't cost an arm and a leg. Start with a good general rifle. Put on a good general scope and mount. I have heard that the Ruger offering is a good value.
Look around, just about every commercial firearm business will have an offering or two. Have a great time learning the gas gun world and a few years out you'll know exactly what you want and can have it built for you or even better, build it yourself.

I wish you the best in your gas gun career. Learn your stuff and the next time you pass through the Bitterroot valley, let me know and we'll go roll pine cones up the hill.