Broken Norinco 1911 slide release

[Homer]

Tuner

As HSMITH noted, check to be sure that the barrel clears the slide when the slide is .250 inch out of battery with a minimum of .010 inch gap. I like .015 better, but .010 will do as long as the barrel drops early enough. With the average Nork vertical dimensions, the amount of clearance shouldn't be a problem...which brings us to the other possible trouble spot.

.012 to .013.

Gun assembled, pull the slide about halfway out of battery and insert a 1/8th
thick shim of some description. A set of ignition feeler gauges stacked together will do. Lacking that, you can whittle a popsicle stick to fit the breechface. Let the slide snap forward with the shim between the hood and slide. Use a dial caliper to measure the distance from the top of the slide to the top of the barrel hood. Pull the shim and let the slide snap into battery, and measure again. Be careful to keep the caliper square on the slide and
barrel to prevent a false reading...Might be good to take three measurements and average the total. The difference between the two dimensions is the amount of vertical lug engagement.

.044 diff ave.

There are two ways to determine which lug(s) are engaging horizontally. The
best method is to gauge the slide and the barrel to see where the lugs are located, and how they match up.

Can you explain how to gauge the slide and barrel?

All else appears to be good..

Thanks again for the advice and solid help.

Homer

 

[1911Tuner]

Gauging

Homer,

Gauging the barrel is pretty simple. Measure from the fce of the hood to the front face of each barrel lug. The slide requires an adjustable fixture that wedges between the breechface and the rear face of each slide lug. Set it,
pull it out, and measure the distance. That lets you determine which lug will come into play first when the hood is cut to let the barrel into the slide. If it happens to be the first lug, you can go with that. If it's the second lug, you can face the lug back until the numbers let the first lug hit at the same time.
I don't like to take more than .005 inch off the adjusted lug face. Then...if tthat brings the third lug to within reach(within about .002 inch)...face the other two back the required distance to bring all three into play, or leave it alone and let the lugs gradually equalize with use as the other two seat and set back. With two lugs bearing the load, that'll take a long time with standard ammo.

For what it's worth...Many smiths fit to the first lug only, and as long as the barrel has good vertical engagement, it'll do nicely for standard-pressure .45 ACP ammo. Your .044 inch is 88% engagement...and that's probably as good or better than your average factory pistol. Full lug equalization isn't absolutely necesary, but it does provide all the strength in the lockup that the gun offers. Trying for equalized lugs isn't recommended unless you start with minimum static headspace because as you face the lugs back, the headspace grows by a like amount. .005 inch lug setback equals an extra .005 inch of static headspace.

Ordnance static headspace measurements are .898 minimum and .920 maximum.

 

[ulflyer]

Mixed Breeds

I have a ColtSpringer and now Homer has a NorColt!

 

[saltydog452]

Isn't that illegal in N.C.?

 

[Homer]

Saltydog....I believe it might be illegal in all fifty states. Appears NorColt it mated just fine and working great.

 

[Homer]

Tuner

Lacking an adjustable fixture, I measured the slide/barrel by eye....with calipers of course. I am assuming the first lug is the one closest to the muzzle? I belive this setup might be bearing on the second/middle lug by .002. Do you feel that this is excessive?

Homer

 

[ulflyer]

Illegal?

Saltydog: Naw, it ain't illegal. They're cousins....

 

[saltydog452]

Pea-patch kin..

 

[1911Tuner]

Measure

Homer posted:

>Lacking an adjustable fixture, I measured the slide/barrel by eye....with calipers of course.<

I'm tryin' to get my head wrapped around how ya did that...
**********************


And:

>I am assuming the first lug is the one closest to the muzzle? I belive this setup might be bearing on the second/middle lug by .002. Do you feel that this is excessive?<

Nope. The third one is closest to the muzzle. If you'd gauge all factory slide/barrel combos precisely, you'd find that the bigest majority do bear on the second lug only. By .002 inch...do you mean that by hitting the second lug, the others are kissing .002 inch of air? (Assuming that your dimensions are correct...which I don't see how they can be.)

 

[Homer]

Tuner

I'm tryin' to get my head wrapped around how ya did that...
I can have that effect on people.....

Measurement of barrel was using Vernier calipers OD jaws. From face of hood to front face of lugs.

Measurement of slide was using ID jaws of calipers. From breech face to rear side of lug.

Slide Barrel
1st lug 1.330 1.303
2nd lug 1.654 1.629
3rd lug 1.982 1.955

I believe I am dead on barrel measurements.
Had to slightly cant calipers to get slide measurements...but got consistant readings.

I will admit, I am easily corn-fused and could have misunderstood your instructions.

Again many thanks..

Homer

 

[Homer]

Tuner

I'm tryin' to get my head wrapped around how ya did that...

I can have that effect on people.....

Measurement of barrel was using Vernier calipers OD jaws. From face of hood to front face of lugs.

Measurement of slide was using ID jaws of calipers. From breech face to rear side of lug.

Slide Barrel
1st lug 1.330 1.303
2nd lug 1.654 1.629
3rd lug 1.982 1.955

I believe I am dead on barrel measurements.
Had to slightly cant calipers to get slide measurements...but got consistant readings.

I will admit, I am easily corn-fused and could have misunderstood your instructions.

Again many thanks..

Homer

 

[1911Tuner]

Numbers

The numbers:

Slide Barrel
1st lug 1.330 1.303
2nd lug 1.654 1.629
3rd lug 1.982 1.955
***********************

Okay...Assuming that your measurements are accurate, the #2 lug will be the one under the load, with the other two kissin' .002 inch worth of air. That's actually not too bad, considering that in time, the bearing lug will probably set back far enough to let at least one of the others come into play. On the downside...by the time that happens, the headspace will increase another .002 inch. If it's well within spec, it won't be much of a problem...but if it's close to max, it could be an issue...depending on a couple of things.

If you have a set of small feeler gauges, you can determine how much horizontal play the barrel has in the slide. Just keep increasing the thickness until the gauge is fairly tight between the hood and breechface. It won't be exact...but it'll be close enough for gub'mint work.

 

[Homer]

Did fire about a box with the new barrel. Checked the slide and barrel and there appears to be some wear on the blueing on the 2nd barrel lug. Have not checked it with go/no go gauge...gotta get with my buddy on that. Left the gun at work, so I will have to check horizontal play this weekend when I go back.

Thanks

Homer

 

[1911Tuner]

Test-Fired

Okay...Looks like your measurements were pretty accurate. Good show!

When you have the headspace gauged...remember that even if it's close to max, it doesn't necessarily mean that the pistol is dangerous to fire. Headspace can be excessive in two directions, and chambering a NO-GO
only means that the total distance from breechface to stop shoulder is beyond ordnance limits. It can be excessive because of excessive space
between rim and breechface that allows the case to back out of the chamber under pressure to the point that the area forward of the case head becomes unsupported by the chamber...dangerous....OR...because the chamber stop shoulder has been cut too deep into the barrel...not dangerous...or it can be a combination of a little of both...which is actually dimensional tolerance stacking against you. Most pistols with excessive headspace is due to this stacking, and a more detailed evaluation is required to determine whether it's safe to fire the gun.

Excessive in the non-dangerous direction...chamber depth...only means that
primer ignition won't be as positive. Erratic ignition may result...or misfires with hard, tough primers is possible, but not likely unless it's really bad.
Erratic ignition isn't conducive to top accuracy, but in an ordnance-spec pistol, you'll never really see the difference.

Excessive in the dangerous direction is a problem. Your first sign will be cases bulged ahead of the web...and even a slight bulge is cause for concern.
If you see it...stop firing the gun and have it tended to. Some brands of brass will show the bulge more readily. If you don't get a bulge with Federal brass, the headspace is probably okay. Winchester and PMC
brass is thick and tough and won't bulge unless the headspace is way beyond the point of dangerous.

 

[Homer]

Tuner

Horizontal play is about .007".

Measured with slide off frame. Starts with about .008" gap between hood and breach. Slide barrel forward and I get .015".

Have not had a chance to check go/no go yet.

Question: What regulates the fit/position of slide to frame? With my old barrel, the slide sat slightly forward off the frame when in battery. With new barrel, the frame and slide mate up flush....as viewed at rear of slide/frame area.

Thanks

Homer

 

[1911Tuner]

Fit

Homer asked:

>With my old barrel, the slide sat slightly forward off the frame when in battery. With new barrel, the frame and slide mate up flush....as viewed at rear of slide/frame area.<
*********************

Generally, the specs at the rear radius of the lower barrel lug determine how the slide and frame mate at the rear...but a tolerance/spec issue between the slide and barrel locking lugs also figure in. In an ordnance-spec pistol,
the barrel is pushed forward by the slide striking the hood, causing the barrel to cam up on the lower lug, or pivot up on the link...if improperly fitted. With clearance between hood and breechface, the slide's locking lug engagement with one or more of the barrel's picks up and carries the barrel into battery the last little bit...and stops as the lower lug hits the slidestop pin.

 

[Homer]

Thanks for the info.

Tuner as always you have a solid answer.

BTW how did the horizontal play look?

Homer

 

[1911Tuner]

Horizontal

Well... .015 inch is a little more than I'm comfortable with. Many factory Colts have as much as .010 or .012 though, and seem to fare pretty well.
I like to see a maximum of .005 inch but there aren't many production guns that are that close unless you go with semi-customs like Wilson, Baer, and Brown etc. Baer takes it to the other extreme, and actually fit them too tight for best go to/return to battery reliability until they've had a thousand or more rounds through'em. Easy to address with a little slurry in the locking lugs and 150-200 hand-cycles though.