I was curious other than the has tubes that expand in diameter. Does anyone make a rifle length gas tube that would work on a carbine length barrel? I want to try and soften the recoil up. I've seen pigtail style but that's for AR pistols. Any thoughts ideas

Or where to find such a thing. Does it exist?

Diameter is not the issue, making the tube wider wouldn't help, plus it may not fit. The diameter at both ends can't be mucked with because it still has to fit the gas block and then fit through the receiver and gas key. At most your would get an expansion chamber in the middle and I suspect that would be a bad idea for timing and consistent pressure reasons. 

 

Realistically you have a couple of options, none of them cheap, if you want soften up recoil

 

0) Get a really good comp. 

1) Get a new barrel with longer gas system, either midlength, intermediate, or rifle.  Hard to make rifle length work reliably on anything other then 18" or longer.

2) Get an adjustable gas block and control the volume of gas the source, but that means taking off the muzzle device and installing a new one because as far as I can tell none one makes a two piece adjustable gas block. 

3) get a lighter weight carrier/buffer. 

 

Ideally you do all of the above combined. 

4) Get a piston system because pistons are better than DI.

PIgtails and flared tubes won't do much for recoil. With a carbine length system, you vent the gas at a point where pressure is crazy high compared to the port position on a rifle length setup. They will drop it slightly, but they are primarily designed to delay unlocking so that the bolt's locking lugs aren't fighting as much pressure (i.e. the space behind the bullet has increased enough to provide a lot more volume for the gas column). you canb cet carbine length pigtails and flared tubes. 

 

http://www.brownells.com/rifle-parts/gas-system-parts/gas-tubes/ar-15-m16-pigtail-gas-tube-prod1591.aspx

 

The usual thing is to go with an adjustable gas block, a decent comp, and fiddle with the BCG and buffer weight as needed. From experience, I can tell you it doesn't change the behavior that much if adjusted to run with a wide variety of ammo all year round with an m-16 styl carrier and a heavy buffer. To get any real difference, you would be wading into the deep end of the pool on gas system tuning/balancing.  Unless you can remove and replace your gas block, you are talking about a barrel replacement anyway to put an adjustable block on. Or you could go with adjustable tube or carrier key. The tubes tend to have their quirks and suck when they fail. 

Am I the only one confused about this question?

Am I the only one confused about this question?

He wants a rifle length gas tube twisted like a pigtail to a carbine length.

Well, he wants to make his gun shoot softer and he was led to believe that the gas tube can help that. In reality, as raz-0 said, the pressure is too high and the dwell time to long to solve the problem with a longer gas tube alone.

He wants a rifle length gas tube twisted like a pigtail to a carbine length.

Oh. I didn't know such a thing existed

 

 

Might not be the solution he is looking for but maybe a voter a5 buffer tube/buffer may help