I too had this problem out of my mossberg 500. I was using a truglo choke and it would shhot to the right. I switched to an HS Undertaker and it is a night and day difference. At 30 yrds I was averaging only 10 to 15 pellets in the kill zone but the center of the shot was still to the right. The new choke put 32 pellets in the kill zone at 30 yrds. I was using the same shell with both chokes. Good luck