Your thoughts on a rifle length gas system with a 16" Barrel.

[strider12]

Hey all. I was looking at this http://www.midwayusa.com/product/951250/del-ton-ar-15-dissipator-a3-flat-top-upper-assembly-556x45mm-nato-1-in-9-twist-16-rifle-length-heavy-contour-barrel-chrome-moly-matte-with-a2-handguard-flash-hider and then I found this comment from Del-Ton's blog.

Currently at DTI, our dissipator style of AR-15 rifle (a 16” barrel with a rifle length gas system) has a true rifle length gas system. Many other manufacturers build this style of AR-15 with a mid-length gas system under the handguards using a low profile gas block; a front sight base (that does not serve as a gas block) is then installed at the typical “rifle-length” location. The main advantage of this style would be the very long sight radius. Possible negative aspects include the weapon being a bit “muzzle heavy” and limitations in ammunition selection (see next paragraph).

Many things can affect the cycling and reliable operation of an AR-15. Multiple variations from the original design have created real benefits for some applications. However, these variations may require additional modifications...or they may create new limitations. Having a mid-length gas system on a 14.5” or shorter barrel, or a rifle length gas system on a 16” barrel (true dissipator) can necessitate an ammunition selection that produces higher pressures. This is due to the distance for the gas pressure required for cycling to travel before most of it escapes out of the muzzle behind the projectile. Some of the less expensive ammunition may use lower quality gunpowder that burns inconsistently; this can result in gas pressure that is inadequate for proper cycling. The weight of the bolt carrier and buffer also play an important role in the cycling of a weapon, so the right combination is necessary for peak performance.​

Any comments on any issues this might have especially from those that may have experience?

Thank you!

 

[ed1380]

Midlenth system on my 16" barrel and never had problems cycling

 

[Kain8719]

Pretty much tells you what issues to expect. Due to the gas block being so far forward with little barrel past it you may not get enough pressure to cycle the rifle. This is a pretty well known issue with most dissipators and the reason some places have made mock dissipators with a FSB past the gas block.

 

[Tiberious]

i just did what i think you are looking to do. i took a mid-length delton sierra moe, moved the sight post out to the end, put a low profile gas block on it w/ rifle length hand guards. works perfectly and i really like the set up a lot. BTW, when i say "I" did it, what i really mean is brian at OTT Guns Works did it for me.

 

[DownSouthMach]

Well i ordered one, well see what happens

 

[NWSharpshooter]

I have two Dissipators. One is a CMMG carbine length gas gun with a YHM low profile gas block and a clamp on A2 FSB at the rifle length location.

The other is a 20" Colt cut down to 16" with rifle length gas. The gas port has been opened up some to accommodate the short dwell length.

Both guns function 100% Really, as long as the gas port is opened up you should have no problems. Take a look at all the 10.5, 11.5, and 12.5 inch SBR uppers that are out there rocking away. Same dwell time. Heck, look at a 7.5 inch SBR upper and the dwell is even less. All of these uppers work because the gas port has been enlarged allowing more gas to pass through the gas system with the shortened dwell time.


I can't imagine Del-Ton would turn out a gun without an enlarged gas port, although to be honest with you I am shocked that anybody is actually making a gun like this. Every factory dissipator I have ever seen has always had mid length or carbine gas under the hand guards.


Also, it should be noted that a "true dissipator" is not Rifle length gas. The term Dissipator was coined by Bushmaster and while they were not the first to do it, they were to first to commercially produce it and give it a name. The original Bushmaster Dissipators were carbine length gas systems with low profile gas blocks under rifle length hand guards.

 

[Chuckdog]

I have one of the DTI's. It has functioned flawlessly.

This is my second Dissy, I'm very partial to these. The long sight radius and short barrel are a great combo.

I roll my own, and have had zero issues using H322, W748, Varget, H335, or any other common .223/5.56 powders. These are the same loads that I use in all my AR's. They include midi's and carbine gassers.

I'd buy another Dissy without hesitation.

 

[strider12]

I have two Dissipators. One is a CMMG carbine length gas gun with a YHM low profile gas block and a clamp on A2 FSB at the rifle length location.

The other is a 20" Colt cut down to 16" with rifle length gas. The gas port has been opened up some to accommodate the short dwell length.

Both guns function 100% Really, as long as the gas port is opened up you should have no problems. Take a look at all the 10.5, 11.5, and 12.5 inch SBR uppers that are out there rocking away. Same dwell time. Heck, look at a 7.5 inch SBR upper and the dwell is even less. All of these uppers work because the gas port has been enlarged allowing more gas to pass through the gas system with the shortened dwell time.


I can't imagine Del-Ton would turn out a gun without an enlarged gas port, although to be honest with you I am shocked that anybody is actually making a gun like this. Every factory dissipator I have ever seen has always had mid length or carbine gas under the hand guards.


Also, it should be noted that a "true dissipator" is not Rifle length gas. The term Dissipator was coined by Bushmaster and while they were not the first to do it, they were to first to commercially produce it and give it a name. The original Bushmaster Dissipators were carbine length gas systems with low profile gas blocks under rifle length hand guards.

Thanks man, that's the.info I needed!!!!

 

[NWSharpshooter]

I have one of the DTI's. It has functioned flawlessly.This is my second Dissy, I'm very partial to these. The long sight radius and short barrel are a great combo.I roll my own, and have had zero issues using H322, W748, Varget, H335, or any other common .223/5.56 powders. These are the same loads that I use in all my AR's. They include midi's and carbine gassers.I'd buy another Dissy without hesitation.

Agree 100% Dissys are my favorite.

 

[Xcaliber]

I like dissys too but I would prefer the mid length gas system on it, no worries about dwell time.