Rifle length gas system on 16" barrel

[IHaveAMustang]

Commonly referred to as "Dissipator"?

Basically I have my first AR-15 I ever built and I am bored with it. Is it possible to buy a 16" barrel with the gas port about 1 - 2" behind the FSB, add a rifle length gas tube and put rifle length MOE handguards on it? Or is there a gunsmith around that can fill the old carbine length gas hole and create a new one wider one further down?

I think that looks dead sexy. I don't want to buy a new upper, just modify my current one.

[CJ]

You would need a barrel with a rifle length gas port.

[BERNIE MOSFET]

You might get a low profile gas block that will fit under full length hand guards and move the front sight forward. This is how my "dissipator" is setup. I love the way the full length hand guards look.

Look into problems with the dwell time on having rifle length gas tube on a carbine length barrel. I've read that there may be issues cycling the carrier group like that.

[CJ]

You might get a low profile gas block that will fit under full length hand guards and move the front sight forward. This is how my "dissipator" is setup. I love the way the full length hand guards look.

Look into problems with the dwell time on having rifle length gas tube on a carbine length barrel. I've read that there may be issues cycling the carrier group like that.

That might work with some specialty FSB, but most barrels gas blocks measure .750" and the barrel will be considerably less than that so the FSB would just be loose. Some of the pin style might work, but I would think they would still be far too loose.

[Mach1Run]

how about swap in a dissy barrel and skip the issues that seem common to rifle gas on a 16"?

http://www.adcofirearms.com/itemdetails_.cfm?inventorynumber=5202

If you hunt around you can fin 18" barrels with rifle gas and the have it cut down.

I an thinking I am going with the adco dissy on my next build, or possible their SPR in 18"

[IHaveAMustang]

You might get a low profile gas block that will fit under full length hand guards and move the front sight forward. This is how my "dissipator" is setup. I love the way the full length hand guards look.

Look into problems with the dwell time on having rifle length gas tube on a carbine length barrel. I've read that there may be issues cycling the carrier group like that.

I've done some reading on Dwell Time. Basically to overcome the reduced pressure (because the gas line has been extended) you have to open the gas port to about .90 = .110. This makes it reliable, but the kick becomes more noticable and the wear on the parts is higher due to a more violent gas kickback.

I was trying not to "cheat" by hiding a carbine length gas block and then adding a new one, but the main reason for me going this route is for looks and maybe so I can get a better sight radius.

Guess it can't hurt. This is my very first rifle and I mangled the FSB up pretty bad trying to tap the pins out when I first started working on AR-15's. Wouldn't make me sad one bit to file it down a low profile and just bolt on a new FSB at the front...

Any pics of yours?

[IHaveAMustang]

how about swap in a dissy barrel and skip the issues that seem common to rifle gas on a 16"?

http://www.adcofirearms.com/itemdetails_.cfm?inventorynumber=5202

If you hunt around you can fin 18" barrels with rifle gas and the have it cut down.

I an thinking I am going with the adco dissy on my next build, or possible their SPR in 18"

This is what I was looking for, but man...that is expensive for just a barrel...

[CJ]

This is what I was looking for, but man...that is expensive for just a barrel...

how much is it?

[Mach1Run]

225$

[CJ]

225$

I paid that for a 9.5" barrel.

[Mach1Run]

I think it's a pretty good price and adco seems to be good to go. I just can't decide to build a Dissy first, or an SPR. Will build them both eventually lol.

[BERNIE MOSFET]

That might work with some specialty FSB, but most barrels gas blocks measure .750" and the barrel will be considerably less than that so the FSB would just be loose. Some of the pin style might work, but I would think they would still be far too loose.

Ah. Perhaps mine has a specialty FSB, then.

I've done some reading on Dwell Time. Basically to overcome the reduced pressure (because the gas line has been extended) you have to open the gas port to about .90 = .110. This makes it reliable, but the kick becomes more noticable and the wear on the parts is higher due to a more violent gas kickback.

I was trying not to "cheat" by hiding a carbine length gas block and then adding a new one, but the main reason for me going this route is for looks and maybe so I can get a better sight radius.

Guess it can't hurt. This is my very first rifle and I mangled the FSB up pretty bad trying to tap the pins out when I first started working on AR-15's. Wouldn't make me sad one bit to file it down a low profile and just bolt on a new FSB at the front...

Any pics of yours?

Ok, yeah I wasn't sure what the fix was to make a full length gas line work. If going for looks, I don't see why not "cheat" at it. I went with the style for the same reason.

Somewhere I've got a picture, but it's standard A2 build with a 16" barrel. Not terribly exciting!

[ThreeFingerPete]

16" rifle gas guns aren't popular in any circles for a reason. They don't run well, they're just too finicky. Grind down your FSB, have steve at Adco pin on a new one in the rifle location and slap on some handguards. Done.

[goofygrin]

Low profile gas block + long quad rail + flip up (or bolt on fixed) front site? Potentially cheaper than a new barrel and/or futzing with the rifle gas system (like I had to in order to get marginal ammo to run reliably -- I had to cut my buffer spring in order to get the bcg to cycle).

[IHaveAMustang]

1 Grind down your FSB, have steve at Adco pin on a new one in the rifle location and slap on some handguards. Done.

That would probably be cheaper than $225. Anyone ever done something like that before? Trying to get a ballpark amount.