16" Anderson A4 Dissipator with Rifle Length Gas System

[prepare]

[RUTGERS95]

love it

[prepare]

Curious about that rifle length gas system with a 16" barrel?

[Todd.K]

Curious about that rifle length gas system with a 16" barrel?

Fun range toy. Too easy to choke with dirt, cold, and / or lack of lubricant for real use. Colt toyed with the idea in the early carbine days but dropped it as too unreliable.

[jsbhike]

Doesn't a Mk 18 have even less barrel past the gas port?

[Slater]

So what does it do that a regular 20 inch barrel won't?

[grizzman]

It'll fit into a shorter gun case, and be easier to use in confined spaces, and........I can't think of anything else.

So what does it do that a regular 16" with mid-length FSB won't? The only answer I can come up with is....nothing. This is especially true with an RDS installed, which negates the increase in sight radius.

If I were forced to use what appears to be a dissipator for anything beyond a range toy (don't have any desire for such a carbine), it'd need to be a mock dissy.

[26 Inf]

So what does it do that a regular 20 inch barrel won't?

They look cock as shit.

Before I retired Sully built us three dissy's with his entry stocks. Nice, smoooth impulse. A mid-length with an A5 or rifle extension and buffer seemed to be just as good.

But the diddy has a high CDIF.

[Disciple]

A page from MicroMOA through Internet Archive on 16" rifle length gas. Might help in trouble shooting if you buy one.

16″ Rifle Gas Competition Setup – Adjustable Gas Tuning

We have tested the following configurations to determine optimal port sizes with this barrel using the MicroMOA Govnah for various common competition configurations. All testing was done with little to no lube and in Florida during summer temps. Ammo used was green box Remington Value Pack .223.
** Special Thanks goes out to RCA Rubber City Amory and Boomfab for their assistance in obtaining these results. **

Carbine Stock Configurations, ‘White Sprinco‘ – standard power spring used for all testing except for JPSCS which is using the standard JP captured spring.
1. .082 – Boomfab Titanium Carrier, JPSCS
2. .089 – Full Weight Carrier, JPSCS
3. .089 – BoomFab Titanium Carrier, carbine buffer
4. .093 – Full Weight Carrier, Carbine Buffer
5. .093 – RCA LW Carrier, Young LW Carrier, Carbine buffer
6. .096 – Voodoo LW Carrier, Carbine buffer
7. .096 – BoomFab Titanium Carrier, H buffer
8. .098 – Full weight Carrier, H buffer

Rifle Stock Configurations, standard power rifle spring used with all rifle stock testing
1. .089 Boomfab Titanium Carrier and Rifle buffer
2. .093 RCA LW Carrier, Young LW Carrier and Rifle Buffer
3. .093 Boomfab Titanium Carrier and Rifle buffer w/ weights removed
4. .096 Voodoo LW Carrier Rifle Buffer
5. .096 Full Weight Carrier and Rifle buffer
6. .099 RCA LW Carrier, Young LW Carrier and Rifle buffer w/ weights removed

We port our 16″ Rifle gas barrels to .101″ to accommodate any of the configurations above.

[Todd.K]

Doesn't a Mk 18 have even less barrel past the gas port?

The velocity increases with a longer barrel. So even if there is the same distance from the port to muzzle there is less time that the port is pressurized.

The pressure drops significantly from carbine to rifle gas, so there is less energy to tap.