I've been using this bag for the last few months and while I really like the material and the 'squeezability' of the bag I've found that for longer strings of firing it gets a little twisted under the stock and if I'm not careful, it can push the stock left/right. Also, because of the use of the zip and the size of the zipper, it opens up. I routinely find those little white plastic pellets on my shooting mat and they're a BITCH to get back in.
If the bag was velco and about 1.5" or so wider then it would be a great bag. I've put in an order for the STR8 Laced bags just to see what it's like with an oversized rear rest.