FWIW, I'm not optimistic that a change in magazine will solve the peening issue. I've used McCormicks after I noticed the peening starting at 2-300 rounds. The peening continued with the McCormicks and at the 1500 round mark I went to MecGars that I currently use and the peening continued to where it is now.
A quote from the link:
After posting the above conclusion, I was contacted by George Wedge, Manager of Quality at Para-Ordnance, who felt I was being unfair to his company's magazines. According to Mr. Wedge, their magazines are manufactured in such a fashion as to guarantee consistency from magazine to magazine. Provided that Para-Ordnance is able to achieve such a feat and all their magazines are exactly the same as the one I examined, it would actually go a long way toward explaining why their service department considers severe peening of the slidelock notch normal wear. It would also go a long way toward explaining the prevalent online myth of the Para-Ordnance "soft slide steel." Most people who use Paras in competition pooh-pooh the assertion that Para-Ordnance's slides are made of inferior steel. My current working theory is that competition usage of Paras is usually done with aftermarket magazines that do not engage the slidelock lug so violently, whereas the people from whom the "soft steel" myth originates use mostly OEM Para mags like as the one reviewed in this writeup. Mr. Wedge also opined that the slide peening was probably an issue with the gun itself and had nothing to do with the magazines, although that explanation does nothing to explain why the Para-Ordnance repair department considered the slide peening normal.
The area that I've highlighted in bold sums up my sentiment but where my opinion differs with Wedge is the peening issue is not an anomoly that affects one or two pistols. The anomoly is if you have one of these pistols that don't exhibit peening.
FWIW, my SSP is currently accurate and reliable so I can't really fault it in terms of performance but how long it will stay this way remains to be seen....