I couldnt resist so I spun one up this afternoon...8.5",8T, set up for a .940 gasblock...It'll probably end up reamed to 308 X 39 but in either case it'll be a hose. Left it heavy to discourage muzzle climb.
Keep in mind that the shorter gas system is probably not optimal for supersonic high pressure rounds, I haven't run quickload on it but I bet it would have too high of pressures.
Jon/mak, Had it out today with 220 rn's over 9 gr VVN 110...ran like a sewing machine...the accuracy was right in there with the 10.5", which was about what I had figured.
I think it is an evolution, not being able to shoot supersonic rounds will be a turn off for some. I'll be making up a fixture for making gas tubes soon.
I didn't have much to go off of with quick load but it looks like pressures will be at least 1.5x on a 125gr bullet traveling 1600fps out of a 7" barrel.
I have a bunch of 160gr bullets that maybe I'll work up a load slowly, from 1000fps to as fast as I am comfortable with.
Spook, your labeling is backwards ;) even if it was pistol position the port would decrease for high velocity.
Funny you guys would think about an adjustable gas block. I ordered one the other day for my 7 inch barrel. Its a PRI low profile adjustable gas block. I got this one because it is the exact size of the non adjustable one I have on it now so I should just have to pop out the gas tube I have already modified from the old one and use it on this one without any more mods.
Now that I think about it some more, It should be feasable with an adjustable block but it might be finicky. I mean think about how finicky 5.56 is through a 7.5" barrel.
If all goes as planned, I'll be shooting some 165gr and more 220gr subs through my barrel tonight.