I picked up a 75D a couple of years ago, for my middle daughter as a college graduation present. Of course it was used, but very little. It doesn't have much wear in the usual areas. I soon found out why.
I've posted about this before but I think I finally figured it out.
It was happening with both of us shooting it and we were both careful to make sure it wasn't a 'thumb' problem. I watched her shoot it several times to make sure she wasn't hitting the slide stop while shooting.
First, with the upper removed and the slide stop in place, I verified that subsequent rounds in the magazine wouldn't contact the stop. I did remove a little material from the stop and even with the next round slid forward, there was plenty of clearance. Then I bought and replaced the retainer spring. This made it more difficult to remove the slide stop/take down lever, like the rest of my CZ 9mms.
I noticed it was always easy to push the slide stop out, leading me to this conclusion.
We still had the problem.
I've been pondering this one for months. Today, I disassembled and looked at the area in the barrel where the cross pin section of the slide stop passes through. That area on the barrel was pretty rough, still showed the machining marks. I assume this was causing the pin to rotate slightly when the gun was cycling. I used a Kratex bit in my Dremel and polished this area, then used a little 15 micron Imprez diamond paste on the Kratex to really make it shine. I polished the pin with some 1,000 grit paper and oil, cleaned everything, oiled and reassembled the gun.
It appears to be working correctly now. I only shot a few magazines worth of ammo through it today, but before this, we couldn't get through a complete mag.
I've been watching for replacement slide stops but they seem to be out of stock everywhere.
In time, I suspect the surfaces would have worn in, but with ammo prices and availability being what they are.....
Anyway, just wanted to post and share in case anyone is experiencing the same problem.
