On my 1911 assembly project, I think I got a little over enthusiastic with my rail lapping. As I was fitting the slide to the frame, it was tight after filing. I began lapping and it was still tight. Then all of a sudden the slide went all the way to the rear and now it seems loose. I think it is fine for shootability but I think it might need to be a little tighter for better accuracy as there is a little wiggle in it. It doesn't slide side to side but it does tilt a tiny lil bit side to side. I was just wondering about suggestions on the best way to fix this. Peening the frame? Squeezing the slide?
I asked this in another post. Blindhogg doesn't recommend trying to squeeze the frame in a vise because apparently it's very easy to crack or over do it. I did read a Brownell's article about using gages and a flat faced hammer to bend the frame rails down, but nothing about side to side.
The reason I asked is because the 1911 I'm working on was 'mil-spec' and is extremely sloppy, but to be honest it sounds like you don't have nearly as much as I do, and I don't know if I would attempt to do this just because it's bugging you that it's not perfect. Accuracy in a 1911 comes more from barrel to slide lockup than frame to slide fit.
Anyway I'm going to probably try and tackle this this weekend on my frame, and I will try to take some pictures.
Alpha precision sells a little tool I believe that is adjustable. Its called a Slide Tightening Stop.
http://www.alphaprecisioninc.com/tools/default.htm
You can set it to the same width as your frame rails and then just slide it into the slide and tighten the slide in a vise until the tool won't slide back and forth any more. Remove it and try the slide on the frame and if its very tight then lap it again. If not you have measured wrongly. To hold the slide in the vice they also sell Slide Tightening Blocks which are on the same page.
One thing to remember is be careful when squeezing the area of the slide where the ejection port is. It's very thin so you can end up making it look like an hourglass and it's very difficult to get back out. If there is vertical play also you can either buy a swaging set from Brownells or use a hammer to roll the edges of the frame over. Brownells sells a slide fitting bar set which works like the Alpha Precision tool but is for vertical play not horizontal.
Thats the professional way. Cheap way for vertical play is to hammer the top of the frame rails at both the front and back of the frame until they roll over slightly. For horizontal play which is what you were talking about you need to squeeze it in the vise with or without the tools I mentioned. You could do it without little by little and just keep trying it on the frame... don't go too far... that's what the tools are for, to stop you going too far. If your're careful you should be okay. Obviously to need to use something to stop the vise from marring the slide. Tools or not up to you.
Another way is to get the Brownells slide fitting bars. Basically the bars are the thickness of the rail on the slide. You then place the bar in the rail cut on the frame. Then you work the rails down to the bars and when it reaches the bars it starts peening them outward. Once they are peened outward enough to take out the slop you then relap the slide in to the frame