Question: I see the beauty of the AR 10…

[Kerf]

It’s calling me hither.

Actually, the STI .400 Corbon project I envisioned got canceled, so I sent a donation for Joplin and Col. Allen West and have decided to go with the AR 10. Never cared much for military type rifles, a la Quigley, but starting to see the need in that direction. I’ve decided to go with the 338 Federal round for starters. (Or, the .45 ACP, and if that, why not the .460 Rowland?) Since I know less than nothing about the AR system, I have a question. (Looked in various forums and on the Internet, even bought several books).

?Has anyone done some decent research, (scientific, of course), regarding the difference in accuracy between the gas piston and the direct impingement method with the AR platform? (I hope I’m using the correct nomenclature there.)

The reason I ask is, I’ve come across people saying that the gas piston is less accurate than the direct impingement. And, I’ve never seen that claim going the other way. Personally, I don’t see that it would make much difference one way or the other. But, not knowing anything about it, and not wanting to go down the wrong road, I need reassurance from you AR types with more experience in such matters. Don’t want to start a border war!

I like the gas piston for the sole reason that you can dial it down and work the bolt manually, and hopefully save the brass for reloading.

Your thoughts…?

Thanks,

kerf

 

[dawico]

Piston guns have more moving parts, therefore are going to be limited on accuracy. But they do run cleaner. Good high quality guns of either type are accurate and reliable, so lets just get that out there.

I have been watching the Scar 17 (piston .308) and there are some guns shooting under MOA (not every group, but a good percentage in my view). I guess the question is how much accuracy do you need? The good DI guns shoot MOA all day, and some down to 1/2 or even 1/4 MOA.

You will just have to find your brass if you want the more accurate gun. Neither gun is very hard on brass if that is a concern.

 

[Rubber_Duck]

Generally for a precision set-up you should stay with DI, The most accurate 7.62mm ARs are all DI, just take a look at the Noveske N6, the LaRue OBR, LMT MWS, and the Knight's SR-25.

OTOH, there are some high quality piston-operated 7.62mm ARs as well such as the LWRC REPR (sorry, only one that comes to mind right now). Do some research on all and decide which is right for you. Novekse offers a gas block called the switchblock which will allow you to shut off the gas for single-shot manual operation if that is important for you.

ETA: Nevermind, Noveske only offers the Switchblock on 5.56mm and 6.8mm barrels, disregard what I said about it for 7.62mm.

 

[Kerf]

Thanks for your info. I guess I'll stick with gas piston on this first one and can always try out the DI system on the next one, if there is a next one. MOA with a 338 I think will be okay.

Thanks again,

kerf

 

[madcratebuilder]

There are several adjustable gas blocks for the 7.62 AR platform rifles available, Noveske offered a switchblock at one time on their N6. DI in the 7.62 runs pretty clean. POF offers a piston 7.62 rifle, read good things about it. There's no free ride, you clean the piston or you clean the bolt.

 

[Zerodefect]

Don't screw around with the gas system. All the more accurate AR10 builds I've seen were all DI.

If you need a bolt action rifle to save wear and tear on brass, then get a bolt action precision rifle.

Besides you can get way more accuracy for your dollar and use hotter ammo like the 6.5 or 6mmbr.

 

[sansone]

There are several adjustable gas blocks for the 7.62 AR platform rifles available, Noveske offered a switchblock at one time on their N6. DI in the 7.62 runs pretty clean. POF offers a piston 7.62 rifle, read good things about it. There's no free ride, you clean the piston or you clean the bolt.

I like the adjustable gasblocks, very few moving parts

 

[Kerf]

Basically, I'm just lazy and don't want to have to chase my brass while at the range, so I thought the gas piston single shot system would work well. Some ranges frown on shooters picking up brass from the range. They grab the brass and sell it as scrap. Or, other people step on it or pick it up, etc.

I have a 6.5-06 bolt gun that shoots 1/2 moa, good 'chuck gun. And, they have the 260 Rem available on the AR platform which looks appealing. Like I say, if I like the first one in 338/gas block, I'll try a DI in 6.5 on the next one and compare the two. I just like the idea of being able to switch the top off from caliber to caliber as needed. Even a 45 acp as a house gun is a possibility.
Thanks again,

kerf