20" Barrel with Midlength gas system?

[LeeEnfieldNo.4_mk1]

Would a 20" barrel and a mid length gas system function? Reason I ask is I think If I pick the components right It could lead to a very interesting looking rifle, especially in .308, the long exposed barrel, with a triangular type of hand guard might resemble a certain type of prohibited firearm we cannot own here.

Any opinions? I am aware I would have to get a custom turned barrel, which I am ok with.

 

[JTF#]

on my 18.5" ACR barrel I used on my AR build it had a mid system. so I am sure 20" will work no problem.

 

[LeeEnfieldNo.4_mk1]

One Thing i was wondering was it might be over gassed with the longer barrel and shorter gas system.

 

[Ar180shooter]

You could likely compensate for that by having a smaller gas hole drilled than normal.

 

[deemoney]

Its a 223 not 308 but thats the way my mossberg mmr(ar15) came from the factory with 20in barrel with a mid length gas system. Its possible mossberg used the same setup on there 308ar hunter.

 

[LeeEnfieldNo.4_mk1]

Since Im going for a certain thing here, I might try out a piston system. a lot of the piston systems have gas regulators so that might help. Will the piston kits for a .223 or similar rifle work with a .308?

 

[Blastattack]

Since Im going for a certain thing here, I might try out a piston system. a lot of the piston systems have gas regulators so that might help. Will the piston kits for a .223 or similar rifle work with a .308?

No, they will not.

 

[F22_RaptoR]

For a DI gun, an adjustable gas block would help. For a piston gun I don't think you'd have too much of an issue, it just means the gun would unlock at the same pressure as a midlength rifle vs a rifle length rifle.

 

[LeeEnfieldNo.4_mk1]

No, they will not.

What prevents them form being used? Would it be due to a longer stroke of the .308 Bolt?

 

[A.T.R.]

The 18" Daniel Defense S2W barrel is midlength, as is the NEA DMR barrel.

So yes, it will work.

 

[Non-phixion]

Personally, if you are running a 18 or 20, rifle length would be preferred.

 

[F22_RaptoR]

What prevents them form being used? Would it be due to a longer stroke of the .308 Bolt?

Some of the general dimensions are different. Even if your gas block seat diameter was the same, the distance from the torque shoulder (where the gas block seats into) to the gas port may be different, the height above bore is usually quite a bit different, and the length of the stroke (the length of bolt travel is irrelevant on a short stroke piston system) is generally different. Not to mention the pressure levels and the weight difference of a .308 BCG and a .223 BCG would make cycling the gun incorrect.

And on top of that, the gas carrier-key on the .308 AR's are not compatible with the OP-rod, and I don't see any way to get a one-piece .308 piston AR10 bolt carrier.