Caldwell makes one that works rather well. I've used it on my AR and XCR-M with no problem. It really is the absolute way to go when shooting off the bench in the winter. I use it in the summer when shooting prone simply because it makes life easier. It does start to sag, but, all it does then it stop the brass from being flung off. I got it at a bass pro in the states for $20. Well worth it, given that the one time I didn't have it with the XCR I lost a pile of brass in the snow due to being on the max gas setting.