Sorry if this sounds like a novice question but I was wondering why the military chose HB's over dissipators when contending with extended full auto fire??  Would a dissipator work the same or better than a heavy barrel???  I'm really not that familiar with dissipators and was wondering if you guys could shed some light..  What exactly are the differences in both with extended rapid fire ??

Thanks!

uhh, I dont know what to tell ya but I have a dissipator that IS a heavy barrel. I guess I could shoot it fast as much as I want, haven't tried it.  It is heavy though, doesnt feel like a carbine at all, more like a full size rifle

I too have a HB Dissy.

Handles FA mag dumps great.

I think the fact a HB heats up slower is very beneficial,
course it does seem to cool down slower.  Yet,
when I compare it to thinner barrels it is an
easy decision.  Go with the HB if you can.

Why would a dissipator help heat issues?  They don't dissipate heat any better unlike the name would suggest.  Dissipators are Bushmasters own creation where they use a carbine (I think) barrel and gas system but mount a low profile gas block instead of the standard FSB and then mount a non functional gas block 12" down the barrel so you can use rifle handguards.  


16" heavy barrel Dissipator


and the real aborted frankenstein that uses a 16" M4 contour barrel in Dissy style:



I've never really liked the looks of them myself.  

Hmmmm...   I always thought that their efficiency in dissipating heat was their intended purpose!  Maybe I should rethink getting one...?  

Their intended purpose was a full-length sight radius on a carbine-length barrel.

Further, I appreciate the fact that I'm much less likely to get burned because there's a lot less exposed barrel.

The reason I built a Dissipator AR was because I liked it. I stand about 5'5" so I really don't like the full size rifles. Most of are too long for me plus ever since I first shot my dad's Inland M1 Carbine I've always liked carbines. I also like the full length sights radius. The A2 stock is just too long for my arms so I bought several like new A1 stocks(going to build a few more ARs for my daughters). My rifle is a Frankenstien. Bushmaster Dissipator barrel, FN upper, Colt bolt carrier group, Olympic lower, and Dpms lower fire control group. How does it shoot? Very good.

i just put this one together, 20" cut down to 16", gas port drilled to .125, lightwieght und handgaurds. to it out yesterday runs perfect with all ammo, did the six mag dump without a hick-up.