OK. Have a brand new RTF G17. I installed an extended mag release and a 3.5# connector and had a gunsmith put on a set of warren tactical sights. Took it for its first shoot yesterday and on the second stage of fire it slide locked open with rounds still in the mag. I did an emergency reload out of habit and when I racked the slide it stayed open. I looked in the chamber and nothing was jammed. Racked it again, still stayed locked open. Pushed the slide release and it shut normally and fired fine for the rest of the stage.
Stage 3, load and make ready, inserted the mag and tried racking it again, nothing, slide stays locked back. I push the slide release and it closes normally, functions properly throughout the stage.
Stage 4 same thing, won't rack shut, but hit the release and it closed and worked fine.
Stage 5, still won't rack closed on load and make ready. I close it with the release and it slide locked open again with rounds in the mag. I pushed the slide release and it closed normally and I finished the stage.
Any ideas what's going on?