So I went off to shoot my old Colt 1911. I thought it was in excellent condition and whatnot, and I got through 2 and a half mags when all of the sudden the slide locked back about halfway. This had happened to me the week before when I was running snapcaps through it (for the lulz). I emptied it out and went home. Just like the first time this happened, I had to actually take a mallet to the slide to get it to return to the closed position so I could disassemble it.

Nothing was visibly wrong when I looked inside, and the rails seemed adequately greased.

What is going on?

I'd really hate to whip this thing out in a firefight and have it go all christopher reeve on me.

better make that first shot count then...

If your slide is binding I'd guess your rails are tweaked. Gunsmith.

so snapcaps actually cycle a weapon?

reg, check the safety and the slide release. Both could be snagging the slide. Happened with my Lugers for years.

my kahr catches on the slide release if i assemble it wrong

No I was just manually cycling them through.

It's not the slide release because it's not getting stuck in the locked position, it's just retracting a bit and then binding.

It sounds like your barrel link is too long. Sometimes when people put those things together, they put a link in that is too long to give it a tighter lockup. It is not a good solution. It could have just stretched out over time too.

That is where I would start. It is an easy fix, you just buy a package of assorted links from Brownells and see which ones work best. You don't want to go too short.

If that doesn't work you will be getting into more expensive modifications. If this is an old army style colt, you might consider something else for self defense. Get a Kimber, you won't have this problem.