Gas tube lengths???

[Robocop1051]

Is there a measuurable difference in ballistics and/or bullet performance when you compare the varying lengths of gas tubes? I have seen every type of barrel-length:gas-tube combination. I'm looking at buying a custom 18" barrel and I want to optimize my performance.

[98Z5V]

The gas tube isn't going to have anything to do with accuracy, unless... 

You can run it too short (think carbine gas tube length in a 20" barrel), and have the rifle cycling extemely hard.  That would have the bolt unlocking very, very fast, and it would kick like crazy (which would wipe out chances of accurate follow-up shots).  In addition, cycling that hard will affect the life of the moving/interfacing hard parts.

It's pretty important on the AR-15s, but the .308s will cycle just about any combination.  I'd go as long as you can on the gas tube length (rifle-length tube), and have it shooting as soft as possible.  Even then, you might be needing a heavy buffer, or Tubb's CWS, in order to soften it up as much as you can.  If you can give your bolt the longest lock time possible, that'll have the greatest effect on follow-up shot accuracy.  Mechanical accuracy of the weapon will depend on other things.

[Robocop1051]

There's nothing longer than "rifle-length"??

[survivalshop]

18 " bbl. , go rifle length gas system .

My 16" with rifle length gas system works just fine .

[survivalshop]

There's nothing longer than "rifle-length"??

Not that I'm aware of .

[cz777]

The gas tube isn't going to have anything to do with accuracy, unless... 

You can run it too short (think carbine gas tube length in a 20" barrel), and have the rifle cycling extemely hard.  That would have the bolt unlocking very, very fast, and it would kick like crazy (which would wipe out chances of accurate follow-up shots).  In addition, cycling that hard will affect the life of the moving/interfacing hard parts.

It's pretty important on the AR-15s, but the .308s will cycle just about any combination.  I'd go as long as you can on the gas tube length (rifle-length tube), and have it shooting as soft as possible.  Even then, you might be needing a heavy buffer, or Tubb's CWS, in order to soften it up as much as you can.  If you can give your bolt the longest lock time possible, that'll have the greatest effect on follow-up shot accuracy.  Mechanical accuracy of the weapon will depend on other things.

this will effect life of the weapon over all ! di system is not so nice if you port before a curtain point in the pressure crave of the barrel ......so why push a weapon to a early grave and you too!

[jeffreyC]

From what I can find about the .308AR, the only time to have a gas tube shorter than rifle length is if it would put the gas block in front of the muzzle.

The .308 has plenty of gas, over-gassing is more likely than under.