Kahr TA5 Pistol Locking Back on every round with certain ammo

[oleroy]

Hello all, first post on the board. Nice to meet everyone.

I recently picked up a Kahr TA5 pistol, and went out to test it today. I noticed some curious behavior and was wanting to see if anyone had any thoughts. The bolt hold open seems to be engaging on shots before the magazine is empty. When it occurs, I can pull back on the charging handle and it will load the next round fine, just the same as if I was loading the first round after inserting a new mag with the bolt held open. When it locks back, the bolt isn't resting on the next round, and I can freely drop the mag and it stays locked back, so its definitely the bolt hold open and not a feeding issue from the magazine. There are zero issues with extracting as far as I can see, and the ejection pattern is extremely consistent as well. This behavior occurred with multiple stick mags I tried.

If I had to make a guess, it seems like the bolt open hold pawl has a weak spring and its allowing the hold open to engage from recoil. This seems to be corroborated by the fact that certain types of ammo trip it way more often than others. I was even able to reproduce it once or twice even after I had removed the magazine and shot a round.


I shot 3 types of ammunition:

Fiocchi 230 grain brass case ball. - This was by far the most problematic. It caused the hold open to engage on nearly every round I tested. I believe this is also the highest ft-lbs ammo I shot.
Winchester 230 grain brass case ball. - This ammo ran comparatively well. I was able to get through 90% of most rounds without having the bolt hold open engage. I think this was the weakest ammo I shot, if manufacture specs are to be believed. That being said, its only a variance of about ~50 FPS/20 ft-lbs from the Fiocchi, so the wild difference in reliability is interesting to me.
My own reloads of 230 grain brass case ball. - I load conservative loads for 45 ACP, so this should be around factory levels. I have yet to chrono to get specifics though. These ran about 80% of the time.



I was thinking of replacing the pawl spring and seeing if it solves the issue. Does this line of thinking track, or does someone else have another suggestion. Also, any tips on replacing the pawl spring? Thanks in advance!

Edited September 5, 2021 by oleroy

[deerslayer]

You have to remove all the lower trigger parts to replace the pawl spring. No tricks just the process. The violence of the bolt movement could be jarring the pawl up to lock the bolt.

[oleroy]

You have to remove all the lower trigger parts to replace the pawl spring. No tricks just the process. The violence of the bolt movement could be jarring the pawl up to lock the bolt.

 

Thanks for the quick response! Do you have a recommended online guide for disassembly of the lower trigger parts? I do a lot of other gun related work, so I am not worried if I have to figure it out myself, but it's always great to have guidance.

[deerslayer]

None that I know of unless somebody's got one on YouTube. Remove the safety first by pulling down the spring loaded pivot plate end. Safety will slide to the left. Then push the pivot plate out to the right. All the trigger parts will come out at that point. Simple.

[Motorcar]

Dan, could weak or short recoil springs cause the bolt to hit the back of the receiver with enough force to be tripping that bolt hold open? A broken pawl spring could do it, do you see that ever?

[deerslayer]

First you need to slide your upper and lower part and see what your pawl looks like.. And is it's still springy..

[Merry Ploughboy]

 

You have to remove all the lower trigger parts to replace the pawl spring. No tricks just the process. The violence of the bolt movement could be jarring the pawl up to lock the bolt.

 

Thanks for the quick response! Do you have a recommended online guide for disassembly of the lower trigger parts? I do a lot of other gun related work, so I am not worried if I have to figure it out myself, but it's always great to have guidance.

The AGI video disc on the Thompsons covers the semi auto as well as full auto versions. That said, one caveat that is in the Owners Manual for the semi that was not specifically noted in the video (at least in the edition that I have) was the warning to make sure that the selector is in the FIRE position before you try to remove the upper from the trigger frame.

 

Disclaimer: I have no affiliation with or financial interest in any vendor or manufacturer; and I am not a competitive shooter or a blogger who receives any form of compensation for endorsements or favorable public or private comments. Use of vendor and/or product brand names, if any, is for informational purposes only.

Best of luck.

MHO, YMMV, etc. Be well.

[oleroy]

None that I know of unless somebody's got one on YouTube. Remove the safety first by pulling down the spring loaded pivot plate end. Safety will slide to the left. Then push the pivot plate out to the right. All the trigger parts will come out at that point. Simple.

 

Thanks for all the help guys.

 

I wanted to confirm that the pawl spring was the cause of the issue, in case anyone else runs into this. Disassembly was easy enough with the pointers everyone gave. I replaced the pawl and pawl spring while I had it apart.

 

 

In case anyone was curious, here is a photo of the pawl and spring, with the left being the old one, and right being the new.