What was the point of the dissipator?

[SoDak]

Ok, maybe I'm just ignorant(fairly likely), but I've had a bushy dissipator for several years and after reading the forum here and getting an m4 style gun, I can't for the life of me figure out why bushmaster made this gun the way they did. Don't get me wrong, I like having the extra sight radius, but why did they make it an hbar. I guess there is a little more stability during rapid fire with a heavy barrel, but why wasn't this thing made with a lightweight or medium weight barrel. Wouldn't it have made more sense since the only reason to buy this gun is for the improved sight radius on a carbine, and an hbar really wouldn't help improve accuacy with iron sight, right? So why not make it lighter and handier by using a light barrel. Does anybody else agree on that. It just bugs me that bushmaster took a nice idea(the carbine with a long sight radius) and then made it an unbalanced and somewhat cumbersome weapon. Can anyone explain to me what bushmaster was thinking when they built this.

[rob_s]

Bushmaster foisted the HBAR on everyone because it was cheaper to make. In an effort not to tell everyone it was cheaper to make, they told you that it was better for you.

[markm]

The dissipator would have also been better with a midlength gas system too. (of course that's hindsight notionalizing now)

Knowing what we know now about the port pressure on rifle vs. carbine gas systems.... the Dissipator is a pretty silly idea.

[m700m]

carbine length, full length sights.