Using the slide release is fine… the slide should not peen. Heat treat issue?
I’m sure more knowledgeable people will chime in.

 

My Ronin (9mm , full size 5") shows some light peening on the slide stop notch. Very slight but it can be felt.

Questions: Is this common? Yes, on suppressed guns that are run dirty, or with extended cap mags (8 for 45acp, etc) that are flush with the frame - that is, they're not purpose-made mags for the capacity, but mags that have an altered/compromised follower that may not fully raise up the slide stop because they can nosedive, even without rounds in it.. Causes? Usually caused by not seating the slide stop fully up in the notch - could be weak mag springs, extremely dirty slide stop/barrel feet/link, badly shaped slide stop notch cut or slide stop itself, bad mags that have had their follower altered to allow loading more than "normal" cap in the mag (like flush fitting 8 round 45acp mags)...usually it's weak mag springs though combined with flush fitting higher cap mags that have compromised/shortened followers to hold more rounds Is it self limiting? No, it'll peen itself out until the slide stop notch no longer works at all Leave it alone or address? If it's not causing failures and if you swap to known good fresh mag springs and it'll fully seat the slide stop, then you can let that sleeping dog lie if you want - otherwise, you might need to re-mill the notch to the correct angles and reblue... Lightly tap raised material back flat or stone and touch up?

I have had one range session with this one but it was purchased used and it may have been there although I don't think so.

I put a 12# Recoil spring in it: Too much spring causing it to hit the stop too hard on last shot?

It had a few failures to lock on the lighter loads.

I was using the slide stop to release the slide on a new loaded magazine. I know better now and will pull back the slide and release (slingshot?) in the future.

Loads ranged from mils Blaser Brass 124 grain to +P 124 grain Gold dots. All factory loads

Observations / advice please

View attachment 1502740

A little word salad above when describing what happens/why, but in general...if someone was shooting this gun suppressed, and if they were using higher-than-standard cap mags for the mag body; they almost always have the rear leg cut down, so the front of the follower can nose dive even when empty and not drive the slide stop all the way fully up into the notch...that will cause the slide stop to only seat part of the way up, and as the gun gets dirtier and hotter the slide stop will go up less and less, until it starts rounding out the bottom edge of the slide stop notch. If you've ever picked up and old gun that if you manually seated the slide stop into the notch, and then shook it and the slide would drop...that's why that would happen. Almost universally on older guns it was caused by shooting with super shitty bad weak mag springs and it wouldn't drive home the slide stop fully. On more modern guns it happens when shooting suppressed, and especially when shooting with 8 round flush fitting mags. The back of the followers have been shortened to fit 8 rounds into a 7 round body, and you can see that most of the time, they won't drive your slide stop fully home, even when dry.

 

I have two Stock Springfield 9 round magazines; the one that came with it and a spare. I also used a Wilson (CMC) Flush 9 round magazine. No modified or increased capacity magazines. The Wilson mag had a weaker spring than the Springers and I have already replaced it's spring.

Here are better photos; they are enlarged and make it look worse than it probably is . The Slide stop is the stock Springfield.

 

Careful stoning will solve the problem.
Double check your slide stop is fitting into the notch correctly
shoot it again and check while shooting if it is starting to raise the edge again.
If so, stop and call SA CS and send it to them.
Ask them to check slide for proper hardness but more importantly for proper slide stop fit.

 

Similar issue on my old Ed Brown KC9. Like curb rash on a wheel, hurts to see but not really hurting anything. Good luck

 

My Ronin (9mm , full size 5") shows some light peening on the slide stop notch. Is this common? Causes?

Here's a close up of your slide stop notch. I've circled the area where the outside edge of the slide stop is making contact and causing peening. It is not at all uncommon for the outside edge of the the slide stop to be relieved by folks to move the contact area inward to prevent peening of the outside edge of the notch.

This is just another example of lack of attention to detailed fitting by the manufacturer. I've been working on a new Springfield Garrison lately. The extractor had multiple issues including a too short hook-to-breechface distance, hook contact with the case bevel, excessive deflection, zero tension, and no blending of the rear of the extractor with the slide. The firing pin stop was a loose fit to the slide and made no contact with the extractor notch which allowed for clocking. There was a burr in the breechface firing pin hole that caused the firing pin to hang up intermittently.

Time is money and manufacturers cut corners to keep their costs down while hoping most of their pistols won't be returned for warranty work.

 

Thank You