Lapping stainless 1911 slide and frame, how loose?

80viking

New member
I just got my ss Caspian slide and have it fitted (by lapping) to a ss frame. Right now there is very little verticle or side to side play and I would consider it done. Do I leave it as is or do I want it a little looser to prevent galling?

Thanks, John
 
I would probably leave it alone. Even though you have stopped lapping, some compound remains behind. Truthfully, you may never remove all of it. Keep the gun well lubed and shoot it. It will likely loosen up some more before it settles down. You don't want it to loosen to the point where you need additional work.
 
Galling wouldn't happen unless the frame was heated, causing it to expand, and rub the slides ways, or dirt was introduced. If the slide was warm, it should actually get looser. All in all, about 0.002" to 0.003" clearance will do, thats a good tight sliding fit. When I say this, I mean overall fit, or 0.001" to 0.0015" per side. Since its a match pistol, I take it, you should always keep it clean, and a thin coat of oil on it. If this is the fit, there shouldn't be any noticeable play in it, especially if it's lapped ultra smooth.

You can check the fit by clamping the frame in a vise, and use a dial indicator to check for side play, and vertical play.
 
Thanks for advise guys. I have been accused of putting too much oil on my guns , so I think I should be ok from where it is right now. I just got it all cleaned up and put together and was test feeding w/ a dummy 9mm round and it will get hung up on the sharp transition from the ramp to the chamber every time, which is actually good because the .45 ramp on the frame is not the problem. I'll just break the sharp edge at the transition and it should go right in.

Thanks again, John.
 
Dixie Gunsmithing gave you a very good answer.

Here's what I do when fitting a Caspian frame and slide (or any slide and frame), I machine the frame rails on my mill to a very close slip fit (.0005 usually works well), then hand lapp the slide and frame with several different grits of lapping compound cleaning the rails between grits, the last compound used is a 1200 grit.

Then I clean the slide and frame thoroughly, lubricate the rails with Gunslick graphite grease, work the slide on the frame as though I'm lapping it.
After the grease is worked in good, with the slide on the frame I tilt the frame and slide at a 45 degree angle with the muzzle end of the slide pointed up, the slide should cylce to the rear under it's own weight moving as though it's on ball bearings.

I keep all my 1911 frame and slide rails lubed with Gunslick grease and have never had a galling problem.

Best Regards
Bob Hunter
www.huntercustoms.com
 
Tight slide to frame fit's been the standard for accurate 1911's forever. How else would the best of them built for .45 ACP wadcutters shoot well inside of 2 inches all day long at 50 yards with good lots of commercial match ammo fired from a Broadway machine rest?
 
1911

Sir;
"slide to frame in a properly barreled pistol influences accuracy hardly at all! of course there are limits but I wouldn't worry about it; other factors are far more importmant.
Greywolf
 
Well, I tested the gun last night.

The good is that it is very accurate and pleasant to shoot and at first it would not completely cycle with the 10 lb spring I had in it. So, I changed it out to a much lighter one and was able to put the 10 lb spring back in after 50 or so rounds. The load is a 124 gr cast bullet with only 3.5 gr of bullseye. Thats the reason for such a light spring. Also I was able to trim down the EGW front sight blank. The gun is perfectly sighted in for that load with the rear sight in the center of its elevation range.

The bad is a feeding problem. The cartridges take a nose dive as they are stripped off the magazine. I have 7 Metalform 9mm mags, some seem to work better than others but none are perfect. I guess my plan is to do a little tweaking and polishing of the feed lips.

Do any of you guys have any tips on mag tweaking? I do realize experience comes into play here.

Thanks, John
 
Ok, these Metalform mags are really starting to irritate me. No matter what I try the top round wants to nose dive into the frame or the mag body itself. Whats happening is once there are more than 5 or 6 rounds in the mag the spring pressure increases then the top round stays in the feed lips where it is supposed to but the rest of them in the mag start to point down leaving the rim to catch the extractor groove of the top one as its being stripped off, causing it to dive into the frame. It reminds me of what the old Luger mags with the round coil springs do.

The gun is done, I just have to get these mags straightened out.

John
 
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John,
I really don't believe the Metalform mags is your problem.
The reason I say this is I've used Metalform 9mm and 38 super mags to feed the custom 9mm hand guns I've built.

The custom 9mm in the picture was test fired with five different brands of factory ammo and one of my favorite 9mm handloads.
I used four different Metalform mags to feed the gun, two were 9mm mags two were 38 super mags, I never had any failures.

I believe you may have a gun problem so I do not recommend you spend more money on mags.
It sounds to me that the gun may still be to tight and you may have a barrel timing issue.
I also feel your 10 pound recoil spring is to light.

Best Regards
Bob Hunter
www.huntercustoms.com
 
Thanks Bob and Geetarman.

Went to my Sunday plate shoot today and was able to look at some other 9mm mags. They were Metalform and Wilson mags. They both do exactly the same thing that mine do when you load them and they are hard to unload by hand because the rims and grooves on the case heads catch on each other, but they don't have feeding problems like mine. One thing that they have that I do not is a longer case oal. I have been feeding a Beretta 92 and a BHP for years on a steady diet of reloads with the Lee tumble lube truncated nose bullets seated up to the last groove with zero problems and they are significantly shorter than a max oal round. I will put together some ammo that is within spec. and test that, hopefully it is that simple a fix.

Thanks all.

John

btw Bob, that 1911 is a beauty.
 
Success!

I really lucked out the other night at Cabelas. The only pistol bullets they had were Rem. 115gr fmj's, 10 bags. The guy said they just came in, I bought them all, anyway I loaded up 100 rounds to an oal of 1.150 and the only jam was because the lips on one of my 7 mags were too close together. After a little tweaking every thing seems to be working 100%. This gun is ready for its first plate shoot on Sunday.

TFL and its members are such a great resource.

Thank you.

John
 
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