Locked breach idiosyncrasies?

[jpshaw]

Most newer, tiny .380's are locked breach. Meaning the chamber block is locked into the ejection port of the slide and is unlocked by the pressure of the round firing and re-locked by the recoil spring bringing it back. All of this happens with the slide moving fairly fast. However, if you will gently push the slide back until this process begins and hold it motionless before releasing pressure the slide can, in some cases, remain in a partially back position due to the friction from these two parts. A bump or slight pressure on the back of the slide should release it. This is common with any locked breach pistol and can happen with a new recoil spring. Please remember this and explain it to the next person, such as the Gun Doctor, who may be actually surfing for information on this forum. Thank you Ronni3_J for trying to help the man and Skiflydive for coming to his defense. Thread was locked before I had a chance to respond.

[Longitude Zero]

380's are a different breed of cat so to speak. Just like 22's are simply straight blowback and thus those quirks. 380 pistols have relatively low mass slides to their bigger caliber sisters and thus have very high recoil spring rates to compensate for the lack of mass in the small guns slides. Due to the relatively light slides, relatively heavy recoil springs the time & tune of a 380 is different, and since the friction between parts is the same no matter what the caliber of the weapon they can and do behave a bit differently. Another possibility as everyone who deals with Kahrs should know or finds out quickly, Kahrs have much tighter chamber tolerances and again with the 380's diminutive size the increased frictional forces could allow unusual operation. If the slide fails to go fully into battery the commonly accepted technique is a sharp blow with the palm of the non-shooting hand to the back of the slide to push it forward into battery.

[muggsy]

It doesn't matter how tight the tolerance the gun should still function properly. You can replace the word tolerance with the word allowance to better understand the concept. Regardless of the tolerance of each individual part they must maintain a functional relationship with each other. That's how tolerances are determined.

[Longitude Zero]

That is assuming each and every part is made to its exact manufacturing specs and that is never the case with firearms. All parts have spec ranges that allow for variance in size. When two parts that should normally fit together smoothly are both fitted up on the large end of the manufacturing specs they can rub and hang up occasionally. Oppositely if they are both made on the small end of the specs they can clank and have issues there. I have experienced complex mechanical devices where all the parts are built to tolerance and it still does not work. Generally that is the case if all the parts tend to be on the large end of the spectrum the term is "Tolerance Stacking" and is well known in the engineering/manufacturing field.

Tolerance is the limit of random (unintentional) deviation of a dimension from its nominal value. Allowance is the amount of designed (intentional) deviation between two mating dimensions in a fit, which, in combination with their respective tolerances, results into a maximum and minimum clearance or interference. Although related in nature they are not congruent and mean different things and thus are not interchangeable terms.

[muggsy]

You shouldn't have to manually push any semi-auto pistol back into battery if it's functioning properly. The Inertia of the slide should take care of that chore. Unless the slide is manually pushed back the slide should stay in battery. If push back manually the slide should return to full battery when released if it is operating normally.

[sas PM9]

You shouldn't have to manually push any semi-auto pistol back into battery if it's functioning properly. The Inertia of the slide should take care of that chore. Unless the slide is manually pushed back the slide should stay in battery. If push back manually the slide should return to full battery when released if it is operating normally.

M:

Apples/oranges.
I agree with what you say, my pm9 (not a 380 obviously) will return to full battery, when manually pushed out of battery, by the action of the recoil springs only.

-steve

[jpshaw]

Some are assuming this quirk to be a fault with the gun. While almost like balancing an egg, I can get almost any properly functioning locked breach gun to hold that set-back somewhere along that cycle of disengaging. Don't assume that it's all points along that cycle but only at a certain "balance" point. Yes, the inertia of the slide will take care of it but when you manually push it back and hold it motionless at the right spot there is no inertia. The point of my post has very little to do with this at anyway. My point was that a newbie asked a legitament question and was ridiculed and even told he needed to use a holster (What) and everything else. I think the poor guy sold his Kahr because he assumed it to be broken. Point of post; Don't ridicule someone for asking a normal question.

[CJB]

Some are assuming this quirk to be a fault with the gun. While almost like balancing an egg, I can get almost any properly functioning locked breach gun to hold that set-back somewhere along that cycle of disengaging.

Well, I tell ya what....

I just tried it on seven Colt 45 autos, a Sig P220, a FNX-45, two Kahr PM45s, a PM9, three Browning HPs (one the competition model), and a Colt 1903 .38 auto. That's the sum total of the locked breech auto loaders handy to me this afternoon. Not one would hang. WWB on the .45, Speer Lawman 124 on the 9mm, and some Winchester Silvertip on the .38 auto (they're 38 Super, same outside, but not to be fired in a 1903 Colt).

Seriously? If I had a pistol that failed to return to battery by pushing the slide back a bit, I'd be looking at ammo size, extractor tweakage, recoil springage, and chamber finish.

[jpshaw]

While ammo can increase the friction I never did it when loaded. Got both by Glocks and my P9 to do it. All at the point that the breach block was entering slide. I'm assuming "Gun Doctor's" recoil spring was worn, which gives you a longer point to hang. Remember you don't balance an egg by just setting it on the table. If you let go too far back you have slide inertia.

[gb6491]

Some are assuming this quirk to be a fault with the gun. While almost like balancing an egg, I can get almost any properly functioning locked breach gun to hold that set-back somewhere along that cycle of disengaging. Don't assume that it's all points along that cycle but only at a certain "balance" point. Yes, the inertia of the slide will take care of it but when you manually push it back and hold it motionless at the right spot there is no inertia. The point of my post has very little to do with this at anyway. My point was that a newbie asked a legitament question and was ridiculed and even told he needed to use a holster (What) and everything else. I think the poor guy sold his Kahr because he assumed it to be broken. Point of post; Don't ridicule someone for asking a normal question.
I imagine that other thread was closed to stop the bickering. Folks, let's not try to rehash it here.
Regards,
Greg

[CJB]

I don't perceive any bickering!

[Newman31Bravo]

Most newer, tiny .380's are locked breach. Meaning the chamber block is locked into the ejection port of the slide and is unlocked by the pressure of the round firing and re-locked by the recoil spring bringing it back. All of this happens with the slide moving fairly fast. However, if you will gently push the slide back until this process begins and hold it motionless before releasing pressure the slide can, in some cases, remain in a partially back position due to the friction from these two parts. A bump or slight pressure on the back of the slide should release it. This is common with any locked breach pistol and can happen with a new recoil spring. Please remember this and explain it to the next person, such as the Gun Doctor, who may be actually surfing for information on this forum. Thank you Ronni3_J for trying to help the man and Skiflydive for coming to his defense. Thread was locked before I had a chance to respond.

So answer this for me in lame terms. If I manually push back my slide on my CW380 and it goes out of battery and I go to pull the trigger with it out of battery will it still fire and work like it should? The slide does not move back far so I could not see it not firing. But if any knows for sure I would really appreciate it cause I just got this one less than a week ago lol


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[jpshaw]

No firearm should fire out of battery unless it's defective but please don't push it back and try to fire a round with it. If you push it back enough it should disengage the trigger. The point of my post was the treatment of a new guy that was ridiculed since his Kahr would end up catching in the re-locking process. It happens, more with weak springs then with new, but no one would address that with him. Yes, he did get belligerent, after a fashion but all in all I believe he was treated badly and so did some others. This was a treating someone fair, issue not a gun issue. If you want to prove it won't set back or if you want to prove it will, you will be successful.

[Bawanna]

I agree he was treated badly and then argument ensued as to weather he was treated badly or not so I shut that one down.

Any gun should not fire if out of battery. My Remington 1911 has a tiny little glitch, if I let the slide down slow it will hang, just a shake will send it home and into battery. It's getting better all the time and it never does it during firing where the cycle is full force.

And it shouldn't do so in this instance either under full force cycle. If it does there is definitely an issue that needs addressed and I suspect more than a recoil spring.

I really think this pony is rode down and doesn't warrant further discussion but carry on as yall see fit.

[CJB]

So answer this for me in lame terms. If I manually push back my slide on my CW380 and it goes out of battery and I go to pull the trigger with it out of battery will it still fire and work like it should? The slide does not move back far so I could not see it not firing. But if any knows for sure I would really appreciate it cause I just got this one less than a week ago lol


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Col. When the barrel drops down, as the slide moves back, will the firing pin still be aligned with the primer?
And, when the slide is rearward, just a smidgen, will the disconnector work as it was designed?

[Newman31Bravo]

No firearm should fire out of battery unless it's defective but please don't push it back and try to fire a round with it. If you push it back enough it should disengage the trigger. The point of my post was the treatment of a new guy that was ridiculed since his Kahr would end up catching in the re-locking process. It happens, more with weak springs then with new, but no one would address that with him. Yes, he did get belligerent, after a fashion but all in all I believe he was treated badly and so did some others. This was a treating someone fair, issue not a gun issue. If you want to prove it won't set back or if you want to prove it will, you will be successful.

Agree, the first guy to respond to him did not know how to read and it pissed him off rightfully so then everyone jumped on him. But thanks for the info bro I appreciate it.


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[CJB]

[QUOTE=Bawanna;358370 just a shake will send it home and into battery[/QUOTE]

Col., this is how I used to fit Bar-Sto barrels.

Most guys would fit them using a cutting tool inserted into the slide stop hole on the receiver.

I did not. Instead, I used a nice little jig, and a fine white wheel on the surface grinder to cut the "pin" part of the underlug.

The jig allowed removing, and replacing the barrel onto the surface grinder, with so little deviation, it didn't matter.

From there, the "relief" part of the underlug could be cut by the cutting tool.

All of that came after top lug fitment and hood fitment, of course.

.... why use the surface grinder....

The surface finish was essentially final. There was no roughness to the surface, no tool marks to "wear in". And, the amount of material that could be controllable removed was on the order of 1/4 of 1/1000 of an inch.

The tool cut relief was "feathered" into the wheel cut pin area.

Back to your observation -

To me, that would be IDEAL for a newly fit barrel and slide.

As both wore (the barrel more than the slide), I'd expect this to be a total non issue. It might take 500 rounds or so.... the barrels I fit were to bullseye spec, so...looks like you got a good shooter there.

I remember one really fun little faux Officer's. I had a Commander (not LW Commander) slide, who's inside was just smaller than the outside of the Officer's barrel I got from Irv at Bar-Sto. It was an easy fit to use the slide itself as the bushing. Then, the underlug was cut, and it fit tight. My good friend Handy Andy said "its too tight". I went with my gut, and left it as it was. Another friend KJ ported teh barrel with trapezoids, and then we cut the slide with big ovals to allow the ejecta to escape. Bullet lube on cast bullets would foul the bushing area. So... back to Mr. Surface Grinder, I put 12 "splines" into the bushing area, which was easy as there was lots of meat to make those splines. The result... the bullet lube... Rooster Red as I recall... would be forced out the splines and create a real mess on the front of the barrel, but.. it functioned perfectly. Eventually... the barrel wore in, and my friend Bob P got the gun as a parting gift.

[zaitcev]

Col. When the barrel drops down, as the slide moves back, will the firing pin still be aligned with the primer?
And, when the slide is rearward, just a smidgen, will the disconnector work as it was designed?
I think this is a valid question. On any properly designed gun, the firing mechanism is disabled when the gun is out of battery.

Now in the Browning system the barrel may move just a little down, not enough to unlock the slide. By that time, the out-of-battery safety should be engaged already.

I don't have a Kahr .380, but I have a Glock 42 and Browning 1911-380 and I experimented with snap caps a bit. Result is, Glock is safe: its firing pin block engages before the barrel unlocks. Browning is not: there's a smidge of a distance when the slide is unlocked, but hammer can still be dropped and strikes the firing pin. Naturally, the firing pin hits way off center, on the border of the primer cap. However, that may still detonate the cartridge if you're unlucky. Well, double unlucky to drop the hammer onto an unfired round first.

Edit: For the record, none of my pistols hang out of battery, including the .380 guns. I have an XD that did that if pointed vertically up. I replaced its recoil spring and that fixed it. I bought that XD used and put about 1200 rounds on it before I noticed. I agree that the guy who prompted the locked thread should have replaced the recoil spring in his CW380. But instead he pawned the problem onto the next owner.

[Ronni3_J]

I guess I should clarify too. When loaded my pistols do not get hung up but there is a little less tension at the end of the slide. I would say maybe the first 1/4" of movement.



As far as your slide issue, there is nothing wrong. When your gun is cocked with a round in the chamber half of your spring tension is taken up, that's why it's easier to move the slide back.

Remove your ammo from the chamber and dry fire your gun, releasing all tension on the springs. Your slide should be tight and harder to move back at this point.

If you feel something is wrong, give Kahr a call and send it in.

[jpshaw]

When the barrel drops down, as the slide moves back, will the firing pin still be aligned with the primer?

I wouldn't think so. The round in the chamber should then be tilted down too much for the striker to hit it.

[muggsy]

Some are assuming this quirk to be a fault with the gun. While almost like balancing an egg, I can get almost any properly functioning locked breach gun to hold that set-back somewhere along that cycle of disengaging. Don't assume that it's all points along that cycle but only at a certain "balance" point. Yes, the inertia of the slide will take care of it but when you manually push it back and hold it motionless at the right spot there is no inertia. The point of my post has very little to do with this at anyway. My point was that a newbie asked a legitament question and was ridiculed and even told he needed to use a holster (What) and everything else. I think the poor guy sold his Kahr because he assumed it to be broken. Point of post; Don't ridicule someone for asking a normal question.

I did see where anything said by the members of this forum could have been construed as ridicule. The OP claimed to have years of military, gunsmithing and concealed carry experience. This wasn't the first time that he had jumped down someones throat with whom he disagreed. His gun was pawned, he's gone and I don't think that he'll be missed. Nuff said.

[Longitude Zero]

I did see where anything said by the members of this forum could have been construed as ridicule. The OP claimed to have years of military, gunsmithing and concealed carry experience. This wasn't the first time that he had jumped down someones throat with whom he disagreed. His gun was pawned, he's gone and I don't think that he'll be missed. Nuff said.

Agreed.