Which is the best gas system on an AR10 style rifle?

[Mags]

Which gas system do I want on an AR10 styled rifle chambered in 308/7.62x51? I want a pretty light setup so 16 inch barrels are prefered.

Carbine length with 16 in barrel.
Mid length with 16 in barrel.
Carbine length with 18 in barrel.
Rifle length with 20 inch barrel.

 

[hso]

I think you'll see the preponderance of advice as follows:

16 is too short for a 7.62 NATO round. Too much velocity/range and accuracy are sacrificed.

18 is barely tolerable. While you still loose out on velocity/range you can maintain reasonable accuracy out to 500 yards.

20 is about as short as you want to go and still have any reason to shoot that round.

If you insist on a 16 inch barrel look at a 7.62X39 AR.

 

[EdLaver]

16 is too short for a 7.62 NATO round. Too much velocity/range and accuracy are sacrificed.

The op never stated his intended purpose/range. I like my AR10 Carbine just fine, I can make decent hits out to 400 yards using a 1-4x scope and 147 FMJ and even better using 168's.

 

[Mags]

3-500 yards is my planned range.

 

[-v-]

16" will still put you supersonic out to 800 yards. I'm not sure where this 16" barrel = 400 yard accuracy keeps cropping up from. Probably from shooters getting a slight flinch from the amount of blast a 16" produce and throwing their shots and being unable to pattern farther than 400 yards.

18" will put you to about 1,000 yards, and a 24" is good to about 1,500 or so yards.

18" gives you a good middle ground between a 24" rifle and a 16" rifle. The velocity curve of the .308 begins to flatten out right at 16" and gets fairly stable from 18" and on.

If you hand-load, you can squeeze that envelope even farther by loading a fast-burning rifle powder.

I have a 16" and its not bad, but I think 18" gets you the best compromise of weight, range, muzzle blast, and maneuverability for a .308.