Heres another one to consider.
This is the M3 Mcmillan tactical model.
I tried the packs you speak of and found they just lost there shape and lacked the organisation I was personally looking for.
They also I felt struggled with a long gun. This pack lets me carry the rifle butt down and all but the barrel forward of the bipod is protected. I found that when you are muzzle down most packs struggle not to be top heavy with a long barrel.
See pics.. This pack is worth every cent.
Glen makes the best gear going !!