My slide stop does not hold the slide open on the last round. Any comments on what the problem may be.

Multiple options for the reason. Could be a worn slide stop, could be the mag follower isn't hitting it correctly inside the frame, could be a worn mark on the slide itself?

Do a close visual inspection & see if anything is obviously wrong. Then put an empty mag in an empty gun & pull the slide back & slowly let it go forward, riding it with your hand. Does the mag follower engage? If not, try a different mag. If different mags don't do it, could be a bad slide stop?

Good luck!

What mag(s) are you using?

The magazines that are being used is the Colt standard 8 round.

Quoted: The magazines that are being used is the Colt standard 8 round.

Have you tried any other then the Colt mags yet????????????

I have one Novak Mag with the same results.

I had a similiar problem. A small peice of the slide stop had cracked off and there was nothing to enguage against the mag. A new slide stop fixed it right up. Cheap enough.

Quoted: The magazines that are being used is the Colt standard 8 round.

Until you've experienced the same problem with several different magazines you can't rule out magazines. For example if magazines are old and well used, the springs could have become weaker and don't have enough strength left to engage the slide stop. Could also be the innermost portion of the slide stop snapped off (the part the magazines hit) and therefore won't engage.

Will it lock back if you engage the slide stop manually? (Unless there's a serious problem, it should)

Try a few different magazines to see if you can narrow it down to the slide stop as the root of the problem, If you can, you'll save a lot of money since it's easier to replace one slide stop than a number of magazines or springs.

Quoted: I had a similiar problem. A small peice of the slide stop had cracked off and there was nothing to enguage against the mag. A new slide stop fixed it right up. Cheap enough.

Happened to mine many years ago. It was a 1 year old Colt Gov't. I was like WTF!! But I replace it with a Wilson slide stop and it's been fine ever since.