Best rear sand bag for field use?

The CrossTac Tactical Rear Squeeze Bag is Great!!!

Crosstac

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.
 
I wish to retract my comments towards Triad Tactical.

I have just ordered some gear from them and the more I ordered the postage became relatively cheaper.

Steve is a good guy to deal with and offers great customer service.

When he correlates my details I still hope he is willing to fulfil my order.

I will definitely be purchasing more goodies from him in the future.

Sorry Steve.