I have a IZ433 (so basically an Izmash made Vepr-12) and it was having issues running cheap birdshot. The main problem was I had my red dot placed right in the way of the ejecting shells, causing misfeeds. I moved the red dot to the rear of the receiver and that definitely improved my reliability, however I was still experiencing jams or misfeeds every couple of magazines. I polished up the rails, hammer, and the part of the bolt carrier that contacts the rails hoping to get the degree of reliability I wanted using light loads. Now I experience a jam maybe 3-4 times out of about 100 shells. I