6.8 spc gas length

[jeremy44]

Hey guys, I'm needing some suggestions on gas length for my 6.8 spc build. I've seen some 22" and 24" barrels with rifle length but have heard they don't like feeding bullets 90gr and lower. I don't want to go shorter than 18" for I am wanting the accuracy at long range. History has shown me that longer barrels have better accuracy...with the correct twist. Maybe someone has experience with these setups? Thanks

 

[docsleepy]

What do you mean by "gas" lengths?

 

[rcmodel]

Put a rifle length gas system on it for smoother cycling and less recoil.
With a slightly over-size gas port, and an adjustable gas block.

Then you can dial it in with whatever bullet weight you choose to use.

rc

 

[jeremy44]

6.8 gas length

To clarify... Gas tube length. Thanks. That's kind of what a guy at a local gunsmith shop told me today. But, can I drill the orfice in the barrel to match the orfice in the adjustable gas block or do I need to use another method?

 

[snakeman]

I just recommend going the simple route. I've never seen a problem with a carbine or mid length gas system. I have no experience however with a rifle length gas system in that caliber.

 

[68wj]

Rifle gassed 6.8's tend to not favor the light/fast bullets (< 90 gr) because they use fast powders in an efficient case that causes the pressure to drop with such a short dwell time. This is mainly applicable to 20" barrels though. If you are wanting such a long barrel, a rifle length system should be fine since the bore is further from the gas port.

I don't think you will gain as much accuracy as you think with such a long barrel though. Short barrels are stiff and velocity gains in this cartridge are minimal with the longer tubes as it is really designed around carbine performance. Long sticks can be fun though if that is what you want. Look up member floatpilot. He has some good 6.8 data from a 24" AR.

 

[ssyoumans]

Go 18" Mid-length gas, that's what I did. get a quality barrel. That will do more for accuracy than length.

Plenty of people are shooting sub-MOA with 16-18" barrels. Length doesn't help accuracy, just increases velocity approx 50 fps / 2". 6.8 isn't a long range round anyhow, 6.5 would be the ticket for long range and uses long barrel more efficiently than the 6.8 SPC.