slide lock back question on STI Spartan

[rrent]

Hope it okay to post this here as its an Amscor gun

I got to the range with my new STI Spartan -- very accurate no failure to feed or eject at all.

However --- the slide did lock back (as if there was no ammo in the mag) once, twice, as many as three times per mag. I shot maybe 20 mags, with only a couple without this happening.

Details
if I pulled the slide back it would load the next cart. no problem
if I dropped the mag release it would load next cart. no problem
I changed the main spring housing - used the spring and guts from original
I changed the once piece full length guide rod to a Wilson Combat two piece

I only took the factory Novak mag and three Wilson combat
(same problem all mags)

Some thing I changed?
Something I should/can correct?

thanks in advance

[John]

I am not sure what you mean that the pistol will load the new cartridge when you dropped the mag release. Puzzled!

Remove the slide from the pistol and reinstall the slide stop. Then insert an empty magazine. See which area of the slide stop is touching the follower? Now remove the empty mag and insert a loaded one. Check if there is an area of the slide stop that comes close or touches the nose of the round in the mag. You will need to file that area a little, so that there is some space between the slide stop and the rounds. Don't overdo it, the slide stop should still engage the follower, but not touch the rounds.

[wichaka]

Yep, sounds like the lug on the slide stop that contacts the follower is a bit over sized, and needs to be dressed back a bit.