RIFLE LENGTH GAS SYSTEM ON 16IN.BARREL

[newguy]

Considering a new build.

What are your thoughts on a rifle length gas sys on a 16 in. barrel for semi auto only.

What would be the neg's and positives of this system.


I know how highly thought of the middy's are as far as parts wear.

I like the rifle length site system on a 16 in.

Would this be a good set up since I want a fixed FSB and rifle length rail

[kmrtnsn]

The only company that I know that makes a 16" barrel with a rifle radius FSB is Bushmaster and it still retains a carbine length gas system and is 1/9. Why not just go 18"?

[xrayoneone]

Colt tried this with the model 605. It had the full length gas system and the 16" barrel. It was unreliable and only saw limited service.

I have one of the Bushmaster Dissipator barrels and like kmrtnsn says it has the carbine length gas system. The gas system is located in a cut down FSB behind the full FSB. With A2 style hand guards there is no modification needed. Mine is an accurate barrel and I used it to build a retro style carbine with A1 style hand guards on a Colt A1 upper. With those handguards I had to trim a little of the aluminum heat shield to get them to fit. I like it.

Some rail handguards may not fit on this barrel due to the cut down FSB but others seem like they would do fine.

[newguy]

I saw this setup on CMMG web site it got me currious if COLT had bad luck with it maybe its not a good idea

[The_Biased_Observer]

I have an old SP1 upper cut to 16 inches. Took some breaking in to get to where I could fire a mag without a malfunction, since then though it fires m193 reliably.

I don't remember though if the smith enlarged the gas port or anything and I'm currently running a rifle buffer in it.

[spamsammich]

I would think a rifle length 16" barrel wouldn't have enough dwell time and you would have to muck around with port sizes to try and get enough gas in the system to cycle reliably.

[orionz06]

If you want the longer sight radius go with a longer rail. A 13.2" rail will cover the block on a rifle length gas system.

Check this link for images: http://www.laruetactical.com/pics/Ch...ev-3-16-09.jpg

I know LaRue and Troy make rails longer than 13", so you should be set there.

[SPDGG]

If you want the longer sight radius go with a longer rail. A 13.2" rail will cover the block on a rifle length gas system.

Check this link for images: http://www.laruetactical.com/pics/Ch...ev-3-16-09.jpg

I know LaRue and Troy make rails longer than 13", so you should be set there.

+1 Agree. IMHO: Anything 16" the max gas port length would be Mid-Length 9". Which you can find barrels & gas tubes much easier, Has become Std. Items from most vendors. Also, the not so common Intermediate, believe thats 10"??? Would think getting gas tubes for the Int. 10" system would be a lot harder.

[lindertw]

.....

[LOKNLOD]

I used to have a 16" barrel that had been cut down (by a reputable guy who supposedly knew how to get these to run) from a 20" Gov't profile barrel.

I loved the balance, handling, and appearance, but it did not function reliably. It would run for a while if it started out clean and heavily lubed with hot ammo, but would begin short stroking quickly as it got a little fouled. And you could forget about using any .223 or lower pressure ammo. I wanted to keep it to tinker with and make into a KISS plinker, but unfortunately I ended up without the original FSB so I didn't bother.

As others have said, there is a dwell time gremlin at work on these, much like the shorty-short barrels, but I think it's exasperated even further with the longer system. The rifle system has the lower port pressure, and a larger volume gas tube, so it needs even more dwell time to get the gas back to work the action. That's going to require a pretty large gas port to compensate for the lack of barrel forward of the port.