Some ?'s for our AR shooters

[Skinny Shooter]

Catfish, I held a DPMS "super varmint" with scope at cabela's and that thing was a beast for weight. I believe the barrel was a fiull inch at the muzzle. I don't mind carrying around a heavy varmint bolt gun with scope and bipod and have been known to carry two in different calibers but that AR was heavy...
It may have been a package for Cabela's cause I couldn't find it on the DPMS site. It reminded me of this one: http://www.stagarms.com/rightrifles.htm

Rottweiler, I have a buyer who is interested in giving me $500 for the entire gun and the round count is under a thousand. A cantilevered forward mount and reddot mount along with tactical sling are included.
Good to know about the play between the upper and lower.

Remmy has the new (Bushmaster) R15 but it has a slow twist. I believe its a 1 in 12.
Bushmaster made their Predator with a 1 in 8 but it has a 20" barrel. Their 24" Varminter has a 1 in 9.

If you had two barrels with a 1 in 8 twist in 20" and 24", would you see a big velocity difference between the two in shooting out to 600 yards or so with heavy bullets?