STI 9mm Target Master lock up

[old jeff]

I have shot maybe 400 rounds of factory 9mm through my STI Target Master. Last week after firing the last round in the mag (by count of shots), the slide locked closed. So tight I couldn't budge that in the field. I removed the mag and saw no problem with that. The slide would move back about 3/4" (not accurately measured) and the barrel dropped down a bit so I felt the link was pulling properly out of the lugs.

I went back to my shop and used a brass rod and tapped smartly. I had counted the rounds fired and knew there was no round in battery and that was confirmed when the slide opened up. The slide freed up and worked perfectly. I disassembled and check all the components and saw nothing out of ordinary. Cleaned and lightly lubed the pistol and later fired 8 rounds to check function.

I did remember that the slide started not staying open after firing the last round prior to this lock up.

What do you all suggest happened. I will NOT send back to the factory, so how about some pointers.

I am just wondering if the mag is at fault.

Thanks for your help

Jeff

[dtsdave]

I had my dan wesson pointman 9 lock up on me very early in its round count i was not properly lubricationg diring break in. My gun was all stainless. It sure sounds like given the slide lock problem that your rails were dry.

[DWFAN]

Make sure your disconnector rail isnt rubbing the back edge of your magazine. The mag catch in my TargetMaster makes the mag sit so high, that some magazines hit the disco rail.

(having the slide still locked with mag out makes me doubt this, but it's worth a check)

Also, new gun and "lightly lube" sometimes doesnt go together. Oil that puppy up.