Slide Locking Back

[mwpslp]

Here is one I need some help with. I have a Kimber Pro CDP and just got back from the range today. I have previously put 200 rounds of 230 gr. ball through it with no problems. Today I tried to put a 50 rnd. box of 200 gr. Gold Dot through it but had the slide lock back during firing about 10 times. I used these same 2 wilson mags in my Springfield and did not have any problems at all. I was very careful to make sure my thumb was not accidentally engaging the slide stop. It would happen at random. Sometimes after the 1st round in the magazine was shot or maybe the 5th. No real pattern to it. I would pull back on the slide and let it go forward and resume firing until it happened again. As I said maybe 8 or 10 times in 50 rounds. The gun is fairly new with what is now about 250 rounds through it. Any suggestions?

 

[model 649]

Sounds like you're getting contact at the slide stop's arm (that contacts the follower when the mag is empty) by the bullets as they rise in the mag to be fed. make sure the gun is unloaded, remove the slide, and insert a full mag. Take a look at how close the second from the top-most bullet is coming to the slide stop's arm. You can also look for brass marking on that same surface. Usually it is possible to remove a small amount of metal from the arm and correct the trouble, if not, try another hollow-point with a tighter ogive for more clearance in that area. Here is a pic, different gun, same principle. Look at the second bullet from the top and where the little (in this case) arm for the slide stop reaches in to the right of the bullet (I don't have any pix of my 1911 like this so I'm using one from my 1076 that I already have on file). That is the place to look in your gun. Hope this helps you out,
Josh