New Karh OA 1927a1, Intro and Failure to Feed

[Explorer]

Hi everyone! Glad to join this community.

I was looking for a carbine to utilize the same ammo as my 1911 and figured I'd end up with a Hi-Point. Thanks the ammo/firearm shortage they were sold out and I showed my wife that the Tommy was the only carbine on Buds Gun Shop, and possibly anywhere. She said "Is that a problem, that's what you want anyway, right?" (I've been working on a ww2 collection). "Yeah, but the cost!" "But will we be allowed to buy semi-autos in a few years?"

 

Ok, you don't have to tell me twice. And I ordered the last A1 on buds and waited for it to arrive.

 

After spending a week just holding it and cycling it with snap caps (I was having an issue with ejections, but I chalked that up to the massive spring tension that wreaked havoc on the aluminum snap cap ends), I finally took it out to shoot.

I was practicing at close range, 20 yards or so, and was drilling holes in the center of the clay targets with the peep site. I have some essential tremors so even at that close range that kind of accuracy is awesome for me. It's a blast to shoot and look forward to drilling targets at farther distances. I mean, the sites say I can lob 45 ACP 500 yards, right? hehehe.

Anyway, the problem is this: I was using CMP issued 230 grain Creedmoor ball ammo and I would get failure to feed every 3-4 shots. Typically, the bolt wouldn't seat all the way (pushing it forward didn't work, but if you relieved tension, then shake the gun to seat the cartridge, it would then go into battery.

 

Unlike the snap caps, ejection with live ammo was great each time; flinging the spent shells 10' or so with such confidence that the guys with me commented on how aggressive the whole firearm looked and sounded.

I've done a bunch of research (how I found the board in the first place) and read about mag issues. I have both a 20 and 30 round. Mine are both OA issues, they claim to be "new", the catch holes are not oblong, but round, and they fit tight into the receiver, sometimes requiring a bit of a slap on the butt to get them to seat. They don't appear to be too low, if anything maybe they need to lock in higher? I'm afraid to grind the hole and lower it.

 

Is there anything I should check before I send it back to Kahr? If at all possible, I'd like to fix this at home; not only because I don't want to ship it off, but because I want to learn more about the firearm.

 

The beast is going to be a blast to shoot...once she's running right.

[BillyDixon]

read all the past post about kahr tommy guns, might answer your questions, my opinon dump this gun as the kahr factory will never get it right, just sayn

[Oldtrooper]

Unfortunately, most Kahr guns are not very dependable in factory condition. I believe that Kahr could ship a dependable gun, but their marketing is all about the weapons appearance and history. (They look cool) Do not simply give up on the weapon, as with some work they can be made to function with a degree of dependability and be fun to shoot.

 

The magazine of the semi auto Thompson is critical in the carbine feeding properly. Magazines made for actual Thompson sub guns will not function dependably without modification to either the magazine itself, (the catch hole - round hole will cause the magazine to sit in the wrong position) or to the magazine catch on the gun. Also critical, are the feed lips on the magazines themselves. Just a little out of spec will cause feed issues. Drum magazines seem to feed the best in these weapons from my experience.

 

Other easily corrected issues are the extractors. They will often pop out of the bolt with a FTF and sometimes jam back into the receiver. This can be corrected by lightly staking the extractor into the bolt. I believe that Kahr has attempted to correct this issue with a screw, but it is hit or miss with this fix working. I staked my bolt in four places and have never had issues with it since. Do not stake so deeply as to make removal of the extractor impossible.

 

Another issue is that the feed ramp is notoriously rough. This can be corrected with polishing the feed ramp.

 

I would advise not dealing with Kahr with any issues mechanically other than catastrophic failure, but rather have your weapon conditioned by a good Thompson mechanic. Dan Block, who goes by the name Deerslayer on this forum is one of the best at making the semi auto Thompson a fun gun to shoot. I sent my semi auto to Dan to install a 10.5 inch barrel when I received my stamp to turn it into a SBR ... Dan put all my 20 and 30 round mags in spec, and replaced any parts that were suspect. He also polished the ramp beyond what I had already done.

 

If you've gone as far as to purchase a semi auto, spending a little more to correct poor quality control is minimal compared to the frustration of the weapon malfunctioning.

 

Just my thoughts.

[Explorer]

Thanks!

I've read a lot of posts about the extractor and ejector issues and I think I'm fine there (for the moment). My issue seems to be either the mag alignment and/or feed ramp. What do you use to polish the feed ramp? And where to find specifications or detailed photos so I can see how a "good" magazine should fit up? Especially the feed lip, as that might be my issues as the fitment of the mag seems good by my untrained eye.

 

Maybe this is a good excuse to splurge on a drum mag and see if I can isolate the issue to the stick mag, hahaha.

These sound like things a reasonable DIYer can tackle themselves, right? I'd like to give it a shot before I figure out how send my firearm off. I'd have to go through the FFL to send it to deerslayer, correct?

 

[Oldtrooper]

Thanks!

 

I've read a lot of posts about the extractor and ejector issues and I think I'm fine there (for the moment). My issue seems to be either the mag alignment and/or feed ramp. What do you use to polish the feed ramp? And where to find specifications or detailed photos so I can see how a "good" magazine should fit up? Especially the feed lip, as that might be my issues as the fitment of the mag seems good by my untrained eye.

 

Maybe this is a good excuse to splurge on a drum mag and see if I can isolate the issue to the stick mag, hahaha.

 

These sound like things a reasonable DIYer can tackle themselves, right? I'd like to give it a shot before I figure out how send my firearm off. I'd have to go through the FFL to send it to deerslayer, correct?

 

 

 

 

On the feed ramp, I began with a fine file, then used a Cratex wheel on a dremel tool. I strongly suggest staking the extractor, as it isn't a matter of if but rather when it will pop out ... I am including a photo of how I staked mine.

 

You can (to my knowledge) ship your firearm to a gunsmith and have it returned to your address without going through a dealer. I sent and received my gun from deerslayer via USPS ... Again I would advise sending Dan a message on here and speak to him directly and make sure that I am correct on the shipping issue.

 

[deerslayer]

Here's one simple look at the problem. New kahr mags are built to wide.. Thus they don't present the round properly to get a good push. A properly modified GI magazine with good shaped feed lips is in the other picture. Just buying a GI mag isn't enough.. Most have squished lips. They may need work.

 

Other jams occur for different reasons. There two main ones are rough interior parts do the bolt doesn't close properly, or firing pin is riding forward with the bolt.

[deerslayer]

GI mag

[deerslayer]

FYI.. USPS rules allow shipping a gun to and from a dealer (like me) directly. Fed ex and ups allow anyone to ship a gun to anyone... You don't have to be a dealer.

[deerslayer]

As the round feeds, a low position will allow the bolt to ride over the rim.

[deerslayer]

As the round feeds, a low position will allow the bolt to ride over the rim.

[Explorer]

Thanks RKI and deerslayer. My OA mags don't seem to seat as low as the ones posted above, but there is noticeable side to side and approx 1/4" if not more slop up and down. That's probably my main issue. However it still looks ok. Is there a way to get it to seat higher without welding and drilling a new hole for the mag?

 

 

Also do you just stake the extractor with a steel punch? How much force? I'd hate to damage the bolt.

Edited February 9, 2021 by Explorer

[Explorer]

First photo was the mag pushed up, and this photo is at "full droop"

[Oldtrooper]

Thanks RKI and deerslayer. My OA mags don't seem to seat as low as the ones posted above, but there is noticeable side to side and approx 1/4" if not more slop up and down. That's probably my main issue. However it still looks ok. Is there a way to get it to seat higher without welding and drilling a new hole for the mag?

 

 

Also do you just stake the extractor with a steel punch? How much force? I'd hate to damage the bolt.

I used a steel punch with the bolt secured in a vise ... Kahr bolts seem to be made of soft steel, so use just enough force to dimple the extractor and bolt.

[deerslayer]

Your auto ord new kahr mags are built bad...too wide...can't fix stupid as they say...

[peter kohler]

send your gun to dan have him do his majic on the feed ramp and modify the mag catch so you can use usgi mags. I have three that run like a top.

[deerslayer]

Take the springs out of your bolt and slide it forward so it touches the bolt face that will give you a good look at where it's hitting the rim. if your mag sits low and you widen the feed lips to get the rounds to sit higher.. then you get double feeds..

 

Add side to side wiggle in firing and feed jams are compounded.

 

Basically if the feed lips on the mag aren't just kissing the bolt as it slides by you are going have problems. How many times do you have to load the magazine before your test ammo cost more than the magazine.

[Butch01]

Ok I too am having problems inserting 20 & 30 round sticks into my semi-auto. The 50 rd drum is ok. But the sticks don't seem to want to seat. Suggestions?

[deerslayer]

There was a combination of old west Hurley lowers that were tight with I think a batch of kahr mags. Have you tried inserting a GI mag?

[katanafred]

 

Take the springs out of your bolt and slide it forward so it touches the bolt face that will give you a good look at where it's hitting the rim. if your mag sits low and you widen the feed lips to get the rounds to sit higher.. then you get double feeds..

Add side to side wiggle in firing and feed jams are compounded.

Basically if the feed lips on the mag aren't just kissing the bolt as it slides by you are going have problems. How many times do you have to load the magazine before your test ammo cost more than the magazine.

 

Hello - I'm new to the forum and also posted this note on an older thread. I recently purchased the Kahr Semi-Auto THOMPSON M1 CARBINE. I switched out the OEM springs for the Howell kit and have been very pleased with the overall performance! I have three of the 30 round stick magazines from Kahr. I fired about 100 rounds among all three magazines and experienced more than a few jams, but all in all not as bad I was expecting.

That being said, I called Kahr and tried to get specs on the magazine lips which the tech I spoke with did not know or didn't understand. He did recommend elongating the magazine catch holes to help seat the magazine better and raise how the magazine sits. So should I be elongating the bottom of the hole or top of the catch hole? My simple ex-grunt mind seems to think that the bottom hole should be elongated, but I am open and will appreciate any suggestions. I like the idea of removing the springs and manually sliding the bolt back and forth to see exactly where and if it kisses the magazine lips as you described!

Thanks!

[deerslayer]

Making your mag hole on a factory kahr magazine more oval advice reminds me of the old joke "I cut it twice and it's still to short"! Doing that will cause the magazine to sit lower and jam more. Enlongating the bottom of the hole is like tits on a boar..

[deerslayer]

Read all the above advice and search my other threads on jams.

[peter kohler]

send your gun to dan. get the easy pull spring set is a big difference in cocking it and your mag catch modified to use un molested original thompson mags. theres still plenty of original mags out there that are cheaper then the new made khar mags... hang in there. im the proud owner of about 4 of these and have dealt with every issue you can think of they all got fixed.

[Burgernut]

Seriously, what the hell is up with Kahr? I've been toying with the idea of buying one of these things for a couple of years. Sometimes I'm put off by lack of availability, then there's the price, $1700+ probably a couple hundred dollars more for mags, mag work, gun tuning, maybe professional assistance. The owners can't get satisfaction by sending them back to the company. It seems some are problematic right out of the box. I'm almost of the belief that they are intentionally trying to run themselves out of business.

[68coupe]

Seriously, what the hell is up with Kahr? I've been toying with the idea of buying one of these things for a couple of years. Sometimes I'm put off by lack of availability, then there's the price, $1700+ probably a couple hundred dollars more for mags, mag work, gun tuning, maybe professional assistance. The owners can't get satisfaction by sending them back to the company. It seems some are problematic right out of the box. I'm almost of the belief that they are intentionally trying to run themselves out of business.

They know they're the only game in town. The only option is to go with the real deal & pay the going price for the real deal.

[UnderwoodFortyFive]

Hi, All. This is my first reply to a topic here, and my first post. My name's Cory.

I have the 1927-A1 also, and am experiencing all of the same symptoms everyone else talks about. I've read as many of these '27-related threads as I can search, and Deerslayer's advice is 100 percent on point. Dan, thank you for that wisdom.

My findings are pretty similar, and my repair/rework plan for the feed ramp and springs is going to be accomplished by a good gunsmith in Gettysburg, PA who works out of Redding's Hardware (a mostly gun shop that sells some Harry Homeowner nuts and bolts also). He works on a lot of off-the-wall things, Gettysburg being a Mecca for re-enactors and their antiquated firearms, and he's locally regarded as reliable. He has a similar KA Thompson to mine, albeit an SBR.

My magazine issues are twofold.

The first difficulty -- making the mix of one each "L" and "X" drums, two KA and two GI 30-round sticks all work as advertised -- is mostly sorted out.

The drums aren't the same; the AO "L" drum is stamped 1928 and it looks quite legit, and the ten-rounder came from KA. The one stamped 1928 is better made. I horse-traded some military-surplus stuff I didn't need for the slightly damaged Gangster-era drum, then gently persuaded it back into usable shape. I got the rifle with the ten-round drum included in the case, and that drum had a dry spring in need of grease. That fix was easy, but I had to make a tool.

The Kahr-supplied stick mags needed help retaining the stamped plate on the bottom and some edge filing on the followers, but now work okay. They still have the 'too-wide magazine' symptom where the bolt only nicks the top eighth of the bullet's cartridge case, but I don't think I can remedy that without reshaping the followers they came with or replacing them outright.

The GI magazines needed light machine work to modify them, but they're now compatible. I ovalled out the too-low factory holes as I'd seen suggested here, but went a little too long in the height aspect. After realizing that, and also realizing that I didn't want to waste the $40 I'd spent on them, I got out my welder.

I drilled two 1/8" holes in the inch of space available over the catch-holes and below the top of the bodies, cut some 1/4" wide strips out of a factory Colt .45 automatic magazine (same thickness of metal) and made my modification by sliding the strips of metal into the slot behind the skins of each magazine's body (inside the rib). It was easy to spot-weld it in place through the holes I'd drilled. The slip of steel was long enough to slide into the catch-hole like a guillotine blade from the back side, and I side-by-side compared them to the KA mags before welding them up. Functionally, they're done. I'll make them pretty later.

However ... The sticks ALL fall out. They just fall right out -- from recoil and lack of lock intrusion into the catch holes in the magazines -- all of which are perfectly placed in order to keep the feed lips and bolt in contact with each other (as described above). My educated guess is that either a) my spring isn't strong enough to keep the catch in place, or b) the business end of the catch isn't either long enough to do the job or isn't shaped right to do its job. My local gunsmith is going to see what he needs to do there, up to and including filing out the inside of the catch where it hits the frame of the rifle, just to get another couple millimeters of forward travel. If I need another one altogether, I have a couple parts from an older gun to donate to the cause -- but I'd like to know what the actual problem with the factory KA part is first.

While he's in there, he's going to replace my extractor, stake the bolt, and see about the Howell spring kit. 

Again, thank you all for the advice and wisdom. It probably sounds stupid, but I really like this thing. I'll like it better when it works like it's supposed to, but I'd rather have it and sleuth my way through this stuff than not have it. 🙂 

Edited December 20, 2023 by UnderwoodFortyFive