I had quite a bit of trouble with my 12f, I found the stock was jamming in the rear bag as the bottom of the stock tapers from the pistol grip to the end of the stock, I ended up making it 5/8ths of an inch wide and parallel, which seems to have help quite a bit, I also modified the front of the stock and added an offset plate which had pretty much stopped the rifle torquing over. I wanted to put it in a SSS dog tracker, but I could not get one from SSS due to export issues