"Dissipator" barrel ?'s

[JMGlasgow]

Talk to me about these type of barrel configurations. I really like the full length sight radius and shorter barrel. I would like to be able to use the standard rifle handguards, or something similar.

Pros/Cons of different gas tube lengths
Would an 18" barrel be better with full length gas system?
What works and what doesn't, if so why?
Can I cut down a 20" barrel to 16" and still make it work?
Would I have to change the buffer?

I am on a budget and looking to be as inexpensive as possible.

Thanks

 

[MontanaMarine]

My Dissipator is a 16" bbl with a carbine length gas system. A mid-length system works with a 16" bbl, but I'm not sure if a rifle length gas system will be reliable with a 16" bbl. I see some 18" barrels out there with rifle-length gas systems.

 

[LRRPF52]

Talk to me about these type of barrel configurations. I really like the full length sight radius and shorter barrel. I would like to be able to use the standard rifle handguards, or something similar.

Pros/Cons of different gas tube lengths 16"/CLGS = too much dwell time, 16"/MLGS = smooth shooter, 16"/RLGS will run well with 5.56, might choke in the cold, gas port dia. dependent
Would an 18" barrel be better with full length gas system? For velocity, yes. They are also quite reliable and smooth. Depending on your height/weight, they may be more difficult to shoot alternate positions with.
What works and what doesn't, if so why? They all work with different mitigating systems, like buffer weight, gas port diameter, and ammunition selection
Can I cut down a 20" barrel to 16" and still make it work? Yes, with the proper gas port dia.
Would I have to change the buffer? Maybe. Have a Carbine 2.9oz, H1, and H2 on-hand if you're worried about it. Take all the ammunition types you think you will shoot, from 45gr HP up to 77gr Match if it applies. If not, just get 55gr and 62gr beater ammo and have at it.

I am on a budget and looking to be as inexpensive as possible.

Thanks

I would not mess with captivated handguards if you are going to shoot any kind of volume in excess of occasional plinking. If you will be blasting 200rds + per session, free-float and don't worry about it again.

 

[JMGlasgow]

Thanks, I'm looking for it to be able to shoot pretty much anything. Having said that, 18" sounds like that is the way to go.

Here is another thought, could I convert my 16" mid length upper to this setup? I would probably go with a Yankee Hill clamp on folding front sight setup, and a low profile gas block for the gas tube.

 

[LRRPF52]

If one of your primary needs is to have a rifle-length sight radius, and you prefer the FSB to be attached to the barrel, then that makes sense, but most people just attach flip-ups to a 12 o'clock rail on a tube handguard that is floated, and use optics as a primary sighting method anyway.

The Dissipator configuration was really nice in the early 1990's before widespread use of optics had really hit the market.

How will you primarily be using this carbine?

 

[JMGlasgow]

I am going to leave it with iron sights. It is already a flat top so if I wanted to put an optic on it I could. Other than that I really like the basic looks, not really into quad rails and such. Simple is better in my opinion. That is why I wanted to use the standard hand guards. If I want to free float the barrel, I'll just install an NM free float tube that goes under the hand guards.