View Full Version : 16" Anderson A4 Dissipator with Rifle Length Gas System
https://youtu.be/nzrqJyRfFjY?si=EmGniYyCb1Y0rvPj
Curious about that rifle length gas system with a 16" barrel?
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.
Doesn't a Mk 18 have even less barrel past the gas port?
So what does it do that a regular 20 inch barrel won't?
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.
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.
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.
A middy 16” with FSB is the practical solution. Maybe someone with very long arms needs the rifle handguards, but it’s mainly just aesthetic preference.
But people forget how handy an A1/lightweight 20” barrel is. An 18” lightweight barrel with FSB would be even better, and much more reliable than the 16” rifle gas.
A page from MicroMOA through Internet Archive on 16" rifle length gas. (https://web.archive.org/web/20141121222022/http://micromoa.com/?page_id=1190) 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.
The MK12 uses a .104” gas port with a longer 18” barrel.
That is a good example of competition and fair weather “runs” vs military reliability “runs”.
That is a good example of competition and fair weather “runs” vs military reliability “runs”.
Indeed. But I would be surprised if anyone here would recommend an Anderson for military reliability anyway.
Indeed. But I would be surprised if anyone here would recommend an Anderson for military reliability anyway.
done well in ukraine so be surprised
I always get a kick out of comments like this given that manufacturing, tolerances for parts, materials etc etc etc have narrrowed in quality over the past 25yrs. You realize that in the stan, those haj goat herders were shooting at us with weapons made in mud casts in some shithole house in pakistan from melted coke cans and you are worrying about modern western manufacturing. laughable
I'm not saying to run out and buy Anderson but at the same time, they go bang
A middy 16” with FSB is the practical solution. Maybe someone with very long arms needs the rifle handguards, but it’s mainly just aesthetic preference.
But people forget how handy an A1/lightweight 20” barrel is. An 18” lightweight barrel with FSB would be even better, and much more reliable than the 16” rifle gas.
middies blow in the cold and will choke in sub freezing temps unless you open them up negating the the 'supposed benefit' of the middy. I say supposed because Crane testing was immaterial. Dissy has the rifle length for longer sight picture before dots were a thing. Has nothing to do with someone needing long arms
So what does it do that a regular 20 inch barrel won't?
Be the same length as a 20” rifle with a MG7k, M4SDk, Turbo T2/3, Sandman k, etc.
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.
what Todd.K says below. I do use my mock dissys with irons, so the sight radius is cool, though not a requirement.
A middy 16” with FSB is the practical solution. Maybe someone with very long arms needs the rifle handguards, but it’s mainly just aesthetic preference.
But people forget how handy an A1/lightweight 20” barrel is. An 18” lightweight barrel with FSB would be even better, and much more reliable than the 16” rifle gas.
Yeah, the A1 handles so light you almost forget its 20”. I do have a lightweight 18” setup in a URX 4, that I might someday pin a FSB to and convert to traditional triangle furniture, and make a 18” A1 not-clone. Its already got an A1 stock, and I think I’ve got another set of A1 handguards around. The A1 receiver is the hard part.
Longer handguards also help when shooting off of some barriers, and with modern rails give you somewhere to mount your nightfighting shit, if applicable. Slightly harder to burn yourself during a transition, also. I’m sure a middy is fine for most people…my Kino has a middy FSB, and I love it.
Brownells, on their retro 605 barrel, used .101. Mine ran OK. Some issues with PMC Bronze .223 not locking back on the last round and it felt lethargic with low power ammo. Never tried it in cooler/cold weather.
I have a 20" A2 cut down to 16" by John Thomas and opened up to .109. No issues. Not as soft as the .101, but it chugs along nicely.
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