Try cci mini mag 40 grain. That's the only round I can get to shoot correctly in mine. My dad went to a gun show with me, I was looking at it. He wanted to get me something for my birthday. He got the gun, I've had it for 30 years give or take. I'm to lazy to look at my receipt.
I always shot the mini mag in it with no problems. Then last summer I tried federal. I was confused the gun was double shooting and triple shoot once! I got home and cleaned the sear real good thinking it was sticking. Went back out, same thing. Got some cci mini mags and it was ok. Tried the federal, nothing but problems again so cci mini mag it is!