My MBA-3's fit just fine, snug but not hard to put on or hard to adjust. Last thing you want is a wiggly stock. The 338 has much larger cheek piece on the factory stock, so I prefer it. The MBA-3's are hard as rock with no soft shoulder pad to absorb recoil. Shot usng 338 with flash suppressor (fits my can to mount suppressot) to get baseline, put suppressor back on real quick, that smarted a bit.