Broken Norinco 1911 slide release

[Homer]

GEEEEZZZE

Well Tuner

I took the throat back to what I thought was flush with the feed ramp. Fired 160 rounds. First 6 mags went off without a hitch. Then I experienced 4 stem binds in the remaining shots. Much much less that before. Got home and checked fit again. Still had very slight overhang as evidenced by barely catching my fingernail. Took slight bit more off and will try later.

Did notice one thing about the fit of barrel to frame....

Look at how far back the barrel sits in the frame pushed all the way back with the slidestop pin installed. Remove the link and check again to see how much difference there is.

No noticable difference.

Checked again and there is about .010 movement to the rear with pin/link removed. Did not notice this until closley checking fit...

I do believe we have gotta er nailed down tho.

Might be a few days before I can try firing it again. Will let ya know tho.

Many thanks

Homer

 

[Homer]

Please

P-32

If you have something constructive to add, brother I'm all ears...er eyes.

HOLD ON! Let me get this straight......A person is advising another to make a barrel ramp correction solely based on what the other said. We also have this problem called "Stem Bind" which is new lingo to me. The pistol has not been properly checked for other possible problems. Then we have a person telling the other to make the barrel ramp correction with no guidance on how to polish the chamber mouth with proper warnings. This a fine area which those with fat fingers can make the barrel unsafe very easily. There is no suggestion of using Go/No go gauges to see if there is room to make a ramp correction or limits on how much to safely go to start with. I understand this isn't rocket science, but I would hate to see the pistol dump hot gases down the mag well.

I would also suggest your "stem bind" might be corrected with a properly tuned mag.

Now, I'm not a pistol smith, but I am a pretty active shooter. But it's still pretty clear to me that dog don't hunt.

I don't think tuning the magazine at this point will help. The cartridge is stopped dead in it's tracks by sharp lower edge of the throat well before reaching the lips of the mag. As for as chamber specs..it was checked good with a Go/No Go gauge. I have only altered the lower edge of the throat and have not touched the upper edge causing a change in the depth/intrusion of the throat into the chamber. Believe me I have experienced a variety of hot gases in my day to make wary..

If you have read the whole thread and have something contrary to what Tuner has advised or can advise on something he has missed I would appreciate it. If not, I do believe the tone of your remarks above are not warranted....

Homer....nope, not a rocket scientist....just a jet engine mechanic.

 

[1911Tuner]

re:

Homer sez:

I took the throat back to what I thought was flush with the feed ramp. Fired 160 rounds. First 6 mags went off without a hitch. Then I experienced 4 stem binds in the remaining shots.

Check for the crescent-shaped mark on the side of the case to see if it's still in stem bind.
*****************

And:

Checked again and there is about .010 movement to the rear with pin/link removed. Did not notice this until closley checking fit...
*********************

If the barrel is moving that much without the link and pin, the link is stopping the barrel under tensile stress...stretch...puts a load on the link and pin that could cause another failure. Go back to the .278 link and check the movement/difference again.

 

[Homer]

That barrel movement was with the .278 installed.

Yep, crescent mark is there....many a piece of my brass bears that ugly scar..

Homer

 

[P-32]

Tuner, I don't mean to fight with you. I have been here for quite some time and mostly post in other areas. If anything my post was to get Homer to slow down a bit. I read your reply about the "Stem" thingy by the way before I posted and you missed my idea. When I was shooting match tuned 1911's back in the late 80's while in the Navy we corrected that problem with a properly tuned mag. Sometimes the mag lips would have to be reformed to get the right angles for feeding the rounds. Alibis are the pits for timed and rapid fire stages (only the low 10 rounds are counted) so we wanted our tight fitting pistols to run with few problems.

The why for my post is because it just so happens I have been reviewing ramp adjustments and head spacing in the Kuhnhausen book before this subject came up as I have a frame which I'm trying to figure out what to do with. I also have a Springer I'm thinking of turning into a Bullseye pistol. I been reviewing the safety rules/warnings, hince my post. I voiced my opinion from the safety aspect. I am concerned with the unknowing grinding on the barrel. The chamber is unsupported to start with and to add more unsupported area is just asking for trouble. There were no instructions/warnings from you. Again the reason for my post. If the pistol were in my hands, I might be able to offer some idea's. But it's not so I won't. That is all. If you think for a second I come here everyday to check up on you, or to stir things up, you sir are greatly mistaken. I very rarely post on gun smith threads on the other web pages I go to often as well. Just isn't my cup of tea, but I had to say something on this subject. If I have sinned then so be it. I stand on my what I believe to be absolutley correct.

It is true I built a pistol with Dave's instruction in 2004. But it is my pistol, I and I alone was responsible for the execution of it's build. My pistol went to the shot show in 2005 because it was a good build and I have the little yellow tag to prove it was there. It was taken apart by some well known smiths in the industry. They were impressed and said I can build a pistol better than 95% of the smiths out there. My slide runs like a mill table. Everyone who has run the slide has gotten a big 'ol smile and commented. A local gun smith said I was loosing money by not building more. And it shoots. Even with that, I do not/will not work on other peoples pistols as I don't have the stamps. I will be building another 1911 with Dave this year in 38 Super.

By the way, way back when I was a reserve Officer and before I went full time, my number was P-32. (Paul 32 was my call sign.) It's a good number and means a lot to me but not as good as the number I have now. I'm number 3 in the Department.

 

[1911Tuner]

Stem Thingy

Paul...P-32...

One...We've been working with Homer on this problem for a while now,
which you would have seen if you had read the entire thread...and the feed issue was secondary to the original problem. When we determined that the
barrel fit and geometry was a player, I've determined that it has to be corrected first, because that stands in the way of any further action having a hope of bearing fruit. Few failures to go to battery are magazine related,
and in the ones that are, the magazine is only a contributor rather than the single cause.

Two...The area that needs to be altered is at the bottom edge of the barrel ramp, and has nothing to do with case head support. Note that no instruction was given to alter the critical TOP area of the ramp. Again...Read before you jump. If I had told him right off the bat to go at his ramp and throat, you'd have had grounds to say WHOA!...but nobody did that.

Three...Your tone and your entrance into the thread didn't indicate
a desire to help, but rather suggested an intent to disrupt. That, sir, is where the problem began. It's a style that I'm all too familiar with. So...If you really do want to help with this diagnosis and correction, I'd suggest that you try a different approach.

 

[1911Tuner]

re:

That barrel movement was with the .278 installed.

Yep, crescent mark is there....many a piece of my brass bears that ugly scar..

Homer

Okay...:banghead:

The mark indicates that the barrel is linking up too early or too abruptly, while the round is still trying to break over. Excessive extractor tension can be a player here. Try taking just a bit of tension off after your finish with the
BOTTOM EDGE OF THE BARREL RAMP.(Not yellin' at you, Homer. Just wanted to make sure that it's not misconstrued by some who may not understand
what that lower edge position relative to the frame ramp means)

Does the barrel ride the link at any point before vertcal/in-battery position?
If it doesn't, the forward radius of the lower barrel lug may be out of spec,
causing the abrupt rise.

Back to the main problem...the broken slidestop pin.

When the barrel unlocks and links down, it should be stopped by the vertical impact surface in the frame rather than by the link. If the link stops it's rearward movement, the link starts to stretch, and it will continue until the barrel is either stopped by the VIS, or it breaks. This effectively lengthens the link, and delays unlock and linkdown timing...possibly to the point of upper lug damage due to the barrel nod dropping early enough to avoid a crash with the lug corners in the slide. If it should stretch to the breaking point, and lets go when the gun is fired, the lugs crash hard...upper locking lugs AND the lower barrel lug. Cracking and/or shearing is the eventual result of that one hard crash.

Meanwhile, this also throws shear stresses on the slidestop pin and the small pin that ties the link to the barrel lug, usually causing the hole to wallow out,
further delaying barrel linkdown timing.

In these cases, sometimes a slightly longer link is called for, along with small adjustments to the top of the hole to relieve the barrel riding or standing on the link...but .010 inch more rearward travel with the link means that it's probably too much to correct with a longer link. As a rule, if you have to go more than .003 inch in either direction, you probably need more than minor
surgery can correct.

 

[Homer]

I'm back

Sorry for the delay...been busy. Had a chance to fire about 200 rounds. With the modification to the lower edge of the throat, the incidence of stem binds has dropped from about 15% to 2-3%. The brass I've been using has been beat up pretty bad...loaded 27 times so far. I have aquired some once fired and will be trying that soon to see if that makes a difference.

In these cases, sometimes a slightly longer link is called for, along with small adjustments to the top of the hole to relieve the barrel riding or standing on the link...but .010 inch more rearward travel with the link means that it's probably too much to correct with a longer link. As a rule, if you have to go more than .003 inch in either direction, you probably need more than minor
surgery can correct.

What kinda major surgery will be required?


Thanks

Homer

 

[1911Tuner]

Sorry for the delay...been busy. Had a chance to fire about 200 rounds. With the modification to the lower edge of the throat, the incidence of stem binds has dropped from about 15% to 2-3%. The brass I've been using has been beat up pretty bad...loaded 27 times so far. I have aquired some once fired and will be trying that soon to see if that makes a difference.

What kinda major surgery will be required?


Thanks

Homer

Okay...We've at least got it headed in the right direction. Maybe we can continue without further interruption from TWKLBTM.

On the lower edge that you set forward...It would have left a flat leading edge just forward of the top of the frame feed ramp. Did you blend that
corner into rest of the barrel ramp, or leave it? If you did blend it, did you blend it enough? If you left it square and vertical at the face, it needs to be smoothed and matched as closely to the rest of the barrel ramp as you can get it without lowering the TOP corner of the barrel ramp or cutting it deeper into the chamber. This is the tricky part in barrel ramp/throat work.

On the vertical impact surface to rear of the lower lug issue...If the lower lug location is the issue...and given the Norinco barrels that I've seen, I suspect that it is...you'll have to rebarrel it. Cross your fingers that it's the barrel
specs and not the frame's. Borrow another barrel from someone and try it in the Norinco...preferably a factory Colt or Springfield barrel...and do the slidestop bind test again. If the slidestop pin is free of any binding, you're golden. A new barrel will likely solve it.

 

[Homer]

I did not blend the throat from the bottom edge to the top. I'll give it a whirl. In the mean time I'll try n locate another barrel.

Thanks again.

Homer

 

[1911Tuner]

re:

I'd consider something other than another Norinco barrel. The pistol's specs
may play a role via tolerance stacking...and you'd wind up with the same or similar situation.

 

[Homer]

Feeding great

Tuner

I have only fired 80 rounds since blending the throat. No binds.

Went to a local gun show Sunday. Could not find any new/used barrels. Couple guys did let me dry fit a couple of barrels from their guns. Both fit good. Even with my old eyes I could see adifference in the lower lug placement on my barrels compared to the others. My lug was definiely mor forward than the other two. Looking at Brownells for replacement.

Thanks Homer

 

[1911Tuner]

No Bind

Outstanding! Good job.

What was happening was that the bullet ogive was hitting that corner and pushing the barrel forward as the round tried to enter the chamber. When the barrel moves forward, it also moves up. If it moves up too early or too abruptly, it puts the round in a bind at three points...The round...the stem...
is caught at three points, and can't continue if the bind is a hard one.

The area that you relieved doesn't support the case head at all...so you can put that bit of misinformation to rest.

Now...on to the second problem..the one that set the barrel ramp too far back to start with. For a quick and easy fix, I've had very good results with
Springfield's stainless service barrels in Norincos. Not a fitted barrel, but not exactly a drop-in either. Light fitting at the hood length was required on two pistols. I've heard that Springfield has stopped offering the barrels...so aftermarket may be your only route.

 

[Homer]

Thanks

Tuner

Appreciate all ur help. I am checking into another barrel. Will let ya know what I come up with.
Homer

 

[1911Tuner]

re:

Tuner

Appreciate all ur help. I am checking into another barrel. Will let ya know what I come up with.
Homer

Mighty welcome, Homer. I wouldn't shoot it much with the link stoppin' the barrel like that. Might stretch/bust the link or another stop pin.

Luck to ya!

 

[Homer]

New barrel?

Tuner

I am unable to find any used barrels. I am looking at Brownell's for replacement. I noticed some "drop-in barrels" listed. What kind of fitting could I be looking at if the "drop-in" is not so drop-in? Would you recommend the mil-spec for for $100 or should I spring for one of the name brands...if so got any favorites?

Homer

 

[1911Tuner]

Barrels

Homer, I haven't used any of the Drop-ins in Brownells for any of my guns so I can't give ya a call on it. One guy that comes down from Tennessee to see me a couple times a year picked up a Nowlin drop-in and brought it to have me chack the fit in a couple of his guns. It needed fitting in one, but dropped into another one nicely...and he reports that the gun is a good shooter.

I did have occasion to try two of Springfield's stainless drop-in service barrels
in two Norincos a while back, and they worked out well...and even required a
little fitting at the rear face of the hood and in the lug slots...but when they
were in the two guns, were tight and provided better than 90% vertical engagement in the slide...and both engaged on the number one lug...with one gun/barrel combo engaging on lugs 1 and 2. Headspace could have been better, but at mid-spec was perfectly adequate for what I wanted to use the guns for. I heard that Springfield isn't selling the barrels to the public any more...but haven't checked on it. I got these two from an individual for a hundred bucks for the pair...which was a little over half-price.

Hard to say what kind of fit that you'll get with any drop-in. Too many variables in the slide and in the slide/frame vertical dimensions to predict.

 

[ulflyer]

New Barrel

Wonder if that new Colt barrel I got would fit? Wouldn't cost no $100. PM if you're interested.

 

[Homer]

Tuner

Is it probable you could talk me throgh fitting a barrel or best left to a smith?

Homer

 

[Homer]

ulflyer

PM sent.

Homer

 

[1911Tuner]

re:

Homer asked:

"Can you walk me through a barrel fit?"
************************

Hi...........

Probably not. It depends on what sort of fit that you want.

Barrel "fit" comes in different degrees. There's "Drop-in" fit, which
means that all dimensions and tolerances allow the barrel to physically
fit inside the gun and function to a workable degree. This is essentially the sort of fit that all production guns have until you get into the high-end price ranges like Wilson and Baer. This could also be termed as "Ordnance" fit.

There's "Semi Drop-in" which includes the fit-down method. The Kart Easy-Fit barrels are of this type, and it's a pretty good system assuming that the gun is mid-spec. The main problem with many Norinco pistols is that they tend to be a little "tall" and don't allow for
full vertical lug engagement with the fit-down method. Not a major problem...IF...the lug location specs get the #1 lug bearing the load
horizontally...AND...the vertical depth is at least 85% of the lug's
height...AND...you don't use a lot of hot-rod ammo. Which leads us to the other unknown. Unless you gauge the slide to determine where the
lugs are located, you don't know which lug(s) are horizontally engaged.

The Kart Easy-Fit comes with raised pads in the slot between the first lug wall and the second lug, plus an overlength hood. It's a very good system, but it assumes that the first and strongest lug will be the one absorbing the stress loads of firing, when in fact, it may not work out that way. When the hood is cut to fit, it may be bearing on lug #2 or even #3, which don't afford the strength of #1. If it happens to be
2 or 3, AND you only have about 70% of the total height (vertical engagement) of the lug...the strength of the lockup isn't what it should be. The gun will still work, and it'll perform pretty well, but it won't hold up under hard use for as long as it should with a full
contact barrel fit.

Since buying the equipment for gauging the slide and correctly fitting the barrel is an expensive proposition unless you plan on doing several
fittings...it's probably best left to a smith who understands how
to do it. The Kart Easy-Fit provides enough leeway to easily adjust for two lugs engaged, which...even with less than 100% vertical depth fo engagment...is much better than only one lug bearing the load.

The true hard-fit barrel has the necessary dimensions to allow the
installer to fit for full vertical depth, and equal horizontal lug engagement on all three lugs...and a semi-finished chamber that allows final static headspace to be set at near-minimum specs. This type of fit produces top acuracy...assuming that the lower lug is correctly fitted...it affords the full potential lockup strength that the design has to offer.


If all you need is a knock-around shooter that'll work and provide acceptable accuracy for general-purpose use...ordnance fit will do.
It worked for hundreds of thousands of USGI pistols and most of the commercial pistols that have been produced since then. Some are very accurate. Some are so-so. Most fall somewhere in between.

If you want upgraded accuracy and better lockup than ordnance fit provides...with the potential for wicked accuracy if the spec gods
are smiling on you...the Kart easy-Fit system is hard to beat. Just order the barrel and kit and follow the directions.

If you want the top-end...the Cadillac...pay a smith to do a full hard fit for you and request equal lug engagement.

It only takes money.

 

[Homer]

FAST

Ulflyer left PM. Got barrel today in the mail. I am working all weekend tho and haven't had a chance to try the fit yet. I do believe that is the fastest I have every gotten anything before through the PO. Thanks for the quick response my friend.

Tuner, will let ya know if I have any problems....

Thanks Homer

 

[Homer]

Tuner

Tuner

Compared old to new barrel. Old barrel has lower lug mounted about a 1/32 more forward on the barrel than the new one. Old barrel slightly overhung fedd ramp. New barrel sits about 1/32 forward of feed ramp. Checked barrel in slide. Gap between hood and breech is slight but even. Barrel installed, cycles fine. Barrel is tight at battery. Checked tension of slide release pin while hanging down, with recoil spring removed and slide to rear by pushing barrel back and down. Slight drag on on release but not a total lock-up as I had with old barrel.

Anything else I should check before firing her up?

Homer

 

[HSMITH]

Make sure it links down far enough to clear the upper lugs. If it does it sounds like it is good to go try out to me.

 

[1911Tuner]

New Barrel

Howdy Homer...Sounds like you may be good to go.

The Norinco barrels seem to have that lower lug issue in common. Most aren't far enough forward to cause the problem that you had...but some do.
Good that the problem wasn't the vertical impact surface location. That woulda been bad JuJu.

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.

Since the Norinco slides tend to sit a little too "tall" in the saddle, the vertical lug engagement may not be all that great. I've seen a few with as little as 50% engagement...and if that's only bearing on one lug horizontally, premature lug deformation and setback will occur.

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.

Ideally, you want all you can get with all three lugs bearing in the horizontal plane...but don't hold out hopes for that. Very few drop-in fit barrels provide full depth OR equalized lugs. The lugs are (optimally) .050 inch high, so .040
inch is 80% engagement. .035 inch is 70% and so on. You want at the very least, 80% of full depth. If you have horizontal engagement on #1...the strongest and most supported lug and 80% depth...the barrel will do pretty well for several thousand rounds. Keep an eye on the barrel lugs for signs of
"stair-step" deformation on the front corners. If it's there, you'll notice a light flange on the top of the lug(s) first. That means that the lug is being slap-seated and the headspace is growing by the amount of deformation.
You might want to determine what the static headspace is before you fire the gun, just to be on the safe side.

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. The other...the "Field Expedient" method,
is to carefully polish the bluing off the front faces of the barrel lugs and color them with a Sharpie marker and go shoot the gun. Be sure that the lugs are dry and free of oil to prevent a false result. The lug(s) that come out clean after about 20 rounds shows which is/are doin' their job and which is/are kissing air when the pressure hits'em.

If your gun doesn't happen to meet the criteria for good lug engagement in both planes, but has safe headspace and functions well, it doesn't mean that it's dead in the water. It's still serviceable...It just won't hold up under hard use. At that point, you can decide whether you want to delegate it to the class of "Carried a Lot and Seldom Shot" or have it repaired. Repair involves swaging the frame rails down and refitting the slide...which, correctly done...
lowers the slide a few thou and allows more vertical lug engagement. From there, you may want to look at having a new "hard-fit" barrel installed in order to optimize the whole shebang. I've had to do this with two of my Norincos. Time-consuming, and expensive if you don't do the work...but the results are very good.

Luck to ya!