Troubleshooting Kahr 1927a1

[HistorianInProgress]

Good evening guys,

I've been trying to troubleshoot my Kahr Thompson, and am hoping you guys have some ideas. The main issue is fail to eject, generally paired with a double feed or a casing stuck in the ejection port. If I manually cycle rounds, I can generally avoid the issue by ensuring the bolt firmly slams into battery; however, if I try to just let it cycle with spring tension its hit or miss.

I took it apart and took a closer look at the extractor, which seems to be working normally: if I push a round over it so as to replicate its function, the extractor latches on pretty well.

I have installed an EZ pull kit, is it possible this is failing to provide enough forward bolt pressure?

Let me know if there are any photos or questions which would be useful for figure it out.

[BillyDixon]

did you buy it new or used ? is this first tiime you try to shoot it ? whst brand of ammo you useing, just askin

[HistorianInProgress]

I bought it new a few years ago and shot it a few mags with the old spring set up. As Irecall, I didn't have these issues before. I've since SBR'd it as well, and have only ever shot it SBR'd with the modified springs. I'm using 230gr FMJ S&B

[BillyDixon]

what short GI style barrel did you put on it? some after market barrels have out of spec chambers, just sayn

[HistorianInProgress]

It's a green mountain installed by Deerslayer, so I'm assuming it's good to go

[HistorianInProgress]

And to further clarify because I have no other experience with Thompsons: if I slowly ride the bolt forward, it locks up just prior to going into battery. If I apply some pressure to the charging knob then I can force it into battery. It's like the bolt needs to slam into battery to engage the extractor. I also notice it's a pretty uncontrolled feed where it strips a round from the magazine, which is then exposed for about an inch before going into the chamber.

Another detail I've noticed is there are three phases of charging the bolt: first there's about a half an inch of take up, then I can feel distinct spring tension, and then I can feel all the springs tensing in the last inch or so. I'm not sure if all or part of that is normal or not.

Edited November 15 by HistorianInProgress

[Countryboy77]

How does your ejector look?

Is it popped through the receiver,double feed is usually a fail to eject and a fresh round,or is it 2 fresh rounds?And if Dan installed the barrel I would imagine he test fired it before sending it to you.

Edited November 20 by Countryboy77

[peter kohler]

are your mags locking in nice and tight?      if they are hanging down a bit you could have a problem there       i bought a mag feed lip tool off this site and made sure all the feed lips were to spec.     did dan do your mag catch so you can use original mags?    

[troll]

My gun didn't like the EZ-pull springs. It seemed to unlock too quickly.

[HistorianInProgress]

Sorry guys, just got back from vacation. I actually emailed Dan earlier this week and he said he'll check it out, no cost. I'll try to take it out again today, also to test a drum I just got, and will otherwise be mailing it to him in the next day or two.

 

To answer you guys though:

Cowboy, here's a photo of my ejector. I assume it's in place correctly, but not sure.

Peter, Dan didn't modify my mag catch to accept surplus. Unfortunately I don't have anything to compare it with, but the issue is present with original Kahr mags as well as a surplus I modified.

Troll, I suppose that's possible. I'm not sure how effective the extractor is supposed to be, but compared to other guns it seems strange I can't reliably, manually cycle the gun.

 

[HistorianInProgress]

Follow up from the range. I'll preface it by saying it's not the best sample size, as I was down to my last box of 45acp; S&B 230gr. I loaded 15 in the drum, and 10 each in one Kahr and one surplus mag. With all three I decided to fire as quickly as I could pull the trigger, and experienced two malfunctions. Both malfunctions were a failure to eject a spent casing (photos attached).

 

I thought the second malfunction was amusing, in that the spent casing managed to completely turn around backwards and the bolt attempted to rechamber it backwards. On the other side was a live round, which was fully chambered.

[peter kohler]

first    unload the gun    then slowly pull the bolt back and see how far into the bolt the ejector id riding   mine is about half way to the middle of the bolt   im wondering if your extractor is fully seated or there may be dirt underneath    again   your mags half to sit tight against the upper part of the receiver.   and your feed lips may be bent   if you had success with all the other mags and the drum then this mag may be the problem

Edited November 25 by peter kohler

[DARIVS]

On 11/24/2024 at 1:45 PM, HistorianInProgress said:

Follow up from the range. I'll preface it by saying it's not the best sample size, as I was down to my last box of 45acp; S&B 230gr. I loaded 15 in the drum, and 10 each in one Kahr and one surplus mag. With all three I decided to fire as quickly as I could pull the trigger, and experienced two malfunctions. Both malfunctions were a failure to eject a spent casing (photos attached).

 

I thought the second malfunction was amusing, in that the spent casing managed to completely turn around backwards and the bolt attempted to rechamber it backwards. On the other side was a live round, which was fully chambered.

The first thing to check is the recoil springs, which may be too light.  Try the rifle with the original springs and see if it fires reliably.

This may be a long shot, but if the bolt face doesn't line up axially with the chamber, couldn't that result in the ejector slipping off the rim upon extraction?  The receiver would have to be milled incorrectly or the chamber be off axis within the barrel, but stranger things have occured with these Kahr rifles.  Ask Dan to check bolt alignment with respect to the barrel.  A cylindrical object that fits precisely in the chamber (similar to that empty case in your photo above) could be inserted and checked against the position of the boltface.

When there is an issue with these rifles, it is often a combination of things which need to be checks to make them behave properly.  My 1927A-1 made in 2000 was SBR'd, and Dan noticed a couple of factors that resulted in the firing pin being snapped off every 800 rounds or so.  In my case, the firing pin guide surfaces were not in tolerance such that the pin would be impacted lightly from the side every time it moved forward.  Multiple impacts eventually snaps off the pin.  The part which acts firing pin is a silly weird shaped piece of crudely stamped hardened sheet steel with a small nub for a pin on the front.  It requires sanding and polishing to move smoothly and sometimes needs to be adjusted in shape to operated in your gun properly, which was second issue.   The base of the nub of a pin has a sharp cornered inside edge, which is a natural stress riser, hence my problem.  Dan had to remove the metal which was being struck by the side of the pin to remove the impact.  That adjustment was not easily assessed.

[HistorianInProgress]

On 11/25/2024 at 8:55 AM, peter kohler said:

first    unload the gun    then slowly pull the bolt back and see how far into the bolt the ejector id riding   mine is about half way to the middle of the bolt   im wondering if your extractor is fully seated or there may be dirt underneath    again   your mags half to sit tight against the upper part of the receiver.   and your feed lips may be bent   if you had success with all the other mags and the drum then this mag may be the problem

Thanks for the tip, Peter. I'll try examining the extractor today. The issue with the mags is actually backwards though: the Kahr stick and repro drum each experienced a failure, and the converted GI mag didn't have one this time; however, it has had similar issues before.

 

On 11/26/2024 at 7:47 AM, DARIVS said:

The first thing to check is the recoil springs, which may be too light.  Try the rifle with the original springs and see if it fires reliably.

This may be a long shot, but if the bolt face doesn't line up axially with the chamber, couldn't that result in the ejector slipping off the rim upon extraction?  The receiver would have to be milled incorrectly or the chamber be off axis within the barrel, but stranger things have occured with these Kahr rifles.  Ask Dan to check bolt alignment with respect to the barrel.  A cylindrical object that fits precisely in the chamber (similar to that empty case in your photo above) could be inserted and checked against the position of the boltface.

When there is an issue with these rifles, it is often a combination of things which need to be checks to make them behave properly.  My 1927A-1 made in 2000 was SBR'd, and Dan noticed a couple of factors that resulted in the firing pin being snapped off every 800 rounds or so.  In my case, the firing pin guide surfaces were not in tolerance such that the pin would be impacted lightly from the side every time it moved forward.  Multiple impacts eventually snaps off the pin.  The part which acts firing pin is a silly weird shaped piece of crudely stamped hardened sheet steel with a small nub for a pin on the front.  It requires sanding and polishing to move smoothly and sometimes needs to be adjusted in shape to operated in your gun properly, which was second issue.   The base of the nub of a pin has a sharp cornered inside edge, which is a natural stress riser, hence my problem.  Dan had to remove the metal which was being struck by the side of the pin to remove the impact.  That adjustment was not easily assessed.

Unfortunately I've since misplaced the original springs, though I don't recall having issues with them (other than the ungodly pull of course). Interesting idea with the bolt alignment though, I imagine he's reading this but I'll shoot him an email when it gets sent out too. I'd meant to send it out before Thanksgiving, but it looks like I brought something home from the airport as first my kid, then my wife, and now me have been laid up in bed sick.

Edited November 28 by HistorianInProgress

[DARIVS]

1 minute ago, HistorianInProgress said:

Thanks for the tip, Peter. I'll try examining the extractor today. The issue with the mags is actually backwards though: the Kahr stick and repro drum each experienced a failure, and the converted GI mag didn't have one this time; however, it has had similar issues before.

 

Unfortunately I've since misplaced the original springs, though I don't recall having issues with them (other than the ungodly pull of course). Interesting idea with the bolt alignment though, I imagine he's reading this but I'll shoot him an email when it gets sent out too. Looks like I brought something home from the airport as first my kid, then my wife, and now me have been laid up in bed sick haha.

Sorry you're under the weather.  Dan will be able to figure the problem out.  Typically magazine issues cause feeding problems and not extraction.  I have seen some strang failures, though, such as an MP-40 that occasionally tries to feed a blank round in the chamber BACKWARDS.  How a blank round with a properly made bullet shaped crimp goes 180 is beyond me, but it did that twice at a reenactment event in the space of an hour.  

[deerslayer]

i know this isn't a semi auto, but slow motion video is one of my tools to figure out why a gun jams.  I was looking for one of my videos but at the moment cant find one.  Most phones have a slow or super slow motion setting.  You can quickly find out if the bolt isn't recoiling far enough, mags not feeding right, or other problems.