Hey guys,  been building a 16" Dissapator for the past couple of months.
Discarded the gas tube with the recycleables....DUMB ASS!

I assume I need the gas tube for the CAR.  Is this correct?

There are only two lengths of gas tubes that I'm aware of, I think you need the rifle gas tube, NOT the carbine length.

Mike

Added: btw, as their both the same diameter (size) I believe it's the "length" that's most important.

Actually there are 3 lengths of gas tubes.  carbine-midlength-rifle

It depends on how you are building the dissy.

If you are doing it like bushmaster, then yes you need the carbine gas tube since the functional gas port is at the carbine location.

There are some other manufacturers (I believe) that use the rifle gas tube, but I think they have to open up the gas port.

Then you could always do your own custom thing and create a dissy out of a midlength barrel.

Basically, you need the tube to match the barrel gas port.  So which barrel did you buy (probably a carbine, maybe a midlength, probably NOT a rifle)?

I'm building it in the Bushy configuration.  I searched their site high and low for which gas tube their dissy used without any luck.  Visually, it seemed more like the carbine but I just wasn't sure.  Thanks for the info Joe.  One more visit from Big Brown and I'll be a happy man.

Quoted: I'm building it in the Bushy configuration.  I searched their site high and low for which gas tube their dissy used without any luck.  Visually, it seemed more like the carbine but I just wasn't sure.  Thanks for the info Joe.  One more visit from Big Brown and I'll be a happy man.

I would call Bushmaster for sure, they have been very helpful when I have called them for tech support.

Realize your "building", but my comments above are based on the fact that Bushmaster sells only 2 gas tubes on their web-site.....

Gas Tube - Standard - $14
Gas Tube - CAR        - $12
Gas Tube Pin             - $0.40

IF your rifle looks like this:


and it has the FSB positioned where Bushmaster positions theirs, (which is where the normal 20" service rifle FSB is positioned) then as stated above you need the "standard/rifle" gas tube.

IF your building a Diss-forgery then it should be a simple process to measure and tell what you've got, either the gas block is shaved off and set-back, up under the handguards/FF tube, OR it's some "mid-length" something or other, wannabe dissy.

Hate to say it, but it doesn't say much for a builder not to have a clue what he needs, one should not toss out parts before having replacements in hand.

Mike

added:  would have been easier to say IF you'd have mentioned WHAT type of barrel your using, a carbine barrel, rifle barrel or this mid-length whatever.....

Quoted: Realize your "building", but my comments above are based on the fact that Bushmaster sells only 2 gas tubes on their web-site..... Gas Tube - Standard - $14 Gas Tube - CAR        - $12 Gas Tube Pin             - $0.40 IF your rifle looks like this: www.bushmaster.com/shopping/uppers/Images/pura2b16d.jpg and it has the FSB positioned where Bushmaster positions theirs, (which is where the normal 20" service rifle FSB is positioned) then as stated above you need the "standard/rifle" gas tube. IF your building a Diss-forgery then it should be a simple process to measure and tell what you've got, either the gas block is shaved off and set-back, up under the handguards/FF tube, OR it's some "mid-length" something or other, wannabe dissy. Hate to say it, but it doesn't say much for a builder not to have a clue what he needs, one should not toss out parts before having replacements in hand. Mike added:  would have been easier to say IF you'd have mentioned WHAT type of barrel your using, a carbine barrel, rifle barrel or this mid-length whatever.....

Someone correct me if I'm wrong, but it is my understanding that the Bushmaster Dissapator uses a shaved gas block, in the normal carbine position, under the guards. The FSB, in front of the handguards, is ONLY a front sight base and does NOT have a gas port under it nor a tube. Gas port is under the shaved block, under the handguards, and uses a normal carbine length gas tube.

The whole purpose of the Dissapator, is to provide a reliable 16 inch barrel rifle with the long sight radius of a 20 inch barrel. Chopping a normal 20 inch barrel down to Dissapator profile, leaving the gas block in the original position, would cause functioning problems due to the reduction of "dwell" after the bullet passes the port and before it leaves the barrel.



Lonny

My friend, just call Bushmaster, It'll save you a headache.

Bushmaster Dissipators use a carbine gas tube.