ARs variations

[kestak]

Greetings,

I know the difference between A2 and A3 : simply carry handle attached on the upper receiver and flat top.

But what about the Dissipator? I can't figure out what is the thing with this one.

Also, what about the mid-lenght? Does that mean the gas is further on the barrel?

Thank you

 

[Bartholomew Roberts]

In the military world, the A2 and A3 both gave fixed carry handles. However, in commercial retail sales, A3 and A4 are used to refer to flattops.

A Dissipator is a 16" barrel with a carbine length gas system and rifle length handguards. It has an extra front sight base in order to give you a rifle length sight radius from a 16" barrel.

A midlength refers to the gas system length. Instead of having it at about 7" (carbine length) or about 12" (rifle length), it has the gas port at about 9" (midlength). The midlength is popular for 16" barrels because it puts the gas port in the place (for that barrel) that lets the cycling times and pressures most clsoely approximate the design of the original 20" barrel.

A general rule of thumb is: 10.5-14.5" barrel = carbine length. 14.5" barrel-17" barrel = midlength, above 17" = rifle length. However those aren't hard and fast limits but approximate limits.

 

[kestak]

Thank you!!

I got it now. Easy to understand.

 

[longdayjake]

Mr. Roberts is correct but left out that some dissipators use a midlength gas system.

 

[Bartholomew Roberts]

Mr. Roberts is correct but left out that some dissipators use a midlength gas system.

True, I described the original "Dissipator" model offered by Bushmaster. These days the term is used more generically to describe any 14.5" or 16" barrel with a rifle length handguard.

 

[MetalHead]

There have even been a few rifle length gas system Dissipators, they have been exercises in frustration.