I used my 2 inch shells in my club's WildBunch match last Saturday and they work great in my M12!!! I had a small hiccup on the first stage where the last two didn't want to feed as smoothly as the other five but I started tilting the sg to the left when racking which solved the problem. If I was confident that I could do it I'd take it apart and cut a chamfer on the inside of the front of the ejection port. I didn't have any trouble rocking the resetting sg targets. I'll use the 2 inch shells again, just need to work on my 2 inch technique.