That's why you use countersunk head rivets. Install them flush to the mag body and they don't touch the mag well. It's not rocket science.As far as rivet material, use Aluminum as it is a softer grade than the magwell lower and should wear before you score the inner magwell. Gouging out the magwell with a stainless steel rivet seems to be less desirable than replacing a $0.05 to $0.10 rivet IMO.