OhioLarry Posted August 3, 2014 Report Share Posted August 3, 2014 (edited) After a year and a half since I first scanned my credit card for the purchase, I received BATF approval and picked up my 1995 West Hurley M1 style Thompson SBR semi-auto. After discovering two things already: bolt won't hold open, new Kahr T11 30-round mag (on the left) won't fit, I thought I might quiz members for any advice before I put any 230gr .45ACP rounds in the magazine. I've read through many of the threads and am in awe of the knowledge here. Edited August 5, 2014 by OhioLarry Link to comment Share on other sites More sharing options...
marcus5 Posted August 3, 2014 Report Share Posted August 3, 2014 See if the magazine catch has been motified to take orginal mags. Link to comment Share on other sites More sharing options...
Paladin601 Posted August 4, 2014 Report Share Posted August 4, 2014 (edited) Welcome to the forum, Larry The receiver is not milled to accept a drum Mag. Looks like you have the M1 version not the 1927. Only the 27 can use Drums. Usually what will cause the bolt not to stay open is the mag follower, not pushing up against the "hold open" , can't think of the name right now. Edited August 4, 2014 by Paladin601 Link to comment Share on other sites More sharing options...
Joe H Posted August 4, 2014 Report Share Posted August 4, 2014 Larry, Exactly what do you mean by "the magazine won't fit"? The bolt hold open won't work unless the magazine is in place. A tab on the magazine follower engages the trip (which you can see in the mag slot) after the last round is fired. Push up on the trip in the mag slot and pull the bolt back it should stay back unless something else is wrong. Joe 1 Link to comment Share on other sites More sharing options...
OhioLarry Posted August 5, 2014 Author Report Share Posted August 5, 2014 (edited) I think "something else is wrong". With no mag inserted, I push up on the LIFT with my finger while drawing back the bolt, but I can't get the bolt to catch in the locked position. As far as the 30-round Kahr mfg. magazine not fitting, it (on the left in picture wants to go no further than half an inch into the frame without squeezing tight. 20-round mag (on the right in picture) that came with the gun inserts easily. Edited August 5, 2014 by OhioLarry Link to comment Share on other sites More sharing options...
Paladin601 Posted August 5, 2014 Report Share Posted August 5, 2014 the mag on the right is a USGI that has been modified for your Thompson the one on the left has not. You can't use a drum on your reciver. Link to comment Share on other sites More sharing options...
Joe H Posted August 5, 2014 Report Share Posted August 5, 2014 Larry. The trip, which is what you pushed on, lifts the pawl which lifts up into a slot on the bottom of the bolt. The end of the pawl could be worn or the end of the slot worn so that the pawl does not hold back the bolt. There is a spring under the pawl that may need to be replaced. Take the receiver off the frame and you will see how it works. If you need to replace the pawl and/or spring the whole fire control has to be disassembled by removing the pivot plate. Just as Paladin noted you are trying to use a USGI magazine in a NK/Kahr semi. You can either modify the mag catch for the USGI mags. (then the Kahr mags won't work) or elongate the hole for the mag catch by .1" on the USGI mags so they will work on the Kahr. The receiver on the Kahr is .1" less in height than the USGI FA receiver which is why the GI mags won't work. Joe Link to comment Share on other sites More sharing options...
emmagee1917 Posted August 5, 2014 Report Share Posted August 5, 2014 Ummmmm , we may be barking up the wrong tree here .The mag on the right IS a modified USGI mag .The mag on the left is NOT USGI , but Karr.Is it not already cut for the semi-autos ?Not into semis , so I don't know for sure , but the hole already looks high.I'd check the thickness of the spine "T" and the gap under the same "T" . Look to see if you can see where it's binding up.Chris Link to comment Share on other sites More sharing options...
mnshooter Posted August 5, 2014 Report Share Posted August 5, 2014 Ummmmm , we may be barking up the wrong tree here . The mag on the right IS a modified USGI mag . The mag on the left is NOT USGI , but Karr. Is it not already cut for the semi-autos ? Not into semis , so I don't know for sure , but the hole already looks high. I'd check the thickness of the spine "T" and the gap under the same "T" . Look to see if you can see where it's binding up. ChrisThe new production Kahr 30 round magazines also have the round hole -not the elongated hole; this hole has been located up about 1/10th inch to work with their factory magazine catches. Their new magazines are unmarked on the front. A year or so ago, a local dealer had ordered some extras for a customer; some were modified GI, others were these new production magazines. They are really quite close to GI in appearance. Put one next to a known GI, and the difference in hole location is obvious. Link to comment Share on other sites More sharing options...
OhioLarry Posted August 16, 2014 Author Report Share Posted August 16, 2014 Well, I wanted to fire my Thompson before commenting further in case something else was wrong, and today I did so. It fired off 20 rounds without malfunction as fast as I could pull the trigger. That pleased me very much as well as did an accuracy test. My 30 round magazine problem got solved when I purchased another mag on GUNBROKER.COM advertised as West Hurley Auto-Ordnance mfg. It arrived today, and I'm happy to say fits my gun like a glove. I will now concentrate on the bolt-lock issue based on the fine advice above. Many thanks to all who took the time to offer help. Great bunch here! I plan to sell the new Kahr manufactured 30 round magazine. Link to comment Share on other sites More sharing options...
dalbert Posted August 17, 2014 Report Share Posted August 17, 2014 OhioLarry, Your M1 semi was manufactured by Auto-Ordnance of West Hurley, NY. (WH) They sold their Thompson/Auto-Ordnance business to Kahr in 1999. West Hurley semi-automatic carbines (Model 1927 and M1) are set up to use magazines that have the elongated magazine catch holes. (Telltale sign is the oval shape) These are the type of magazine you need to look for. I suggest looking for the oval cut on magazines at gun shows. Many folks have converted their WH semis to accept USGI magazines, and the oval magazines are less desirable to most Thompson folks, so you may be able to find someone who wants to get rid of theirs. We've learned something from this post that is news to me...New Kahr magazines have the USGI mag catch setup. I'm not sure if their earlier magazines had the oval catch hole. Good to know... I'm glad you had fun shooting your new SBR, and that it functioned flawlessly. David Albertdalbert@sturmgewehr.com Link to comment Share on other sites More sharing options...
deerslayer Posted August 18, 2014 Report Share Posted August 18, 2014 New kahr mags are a little bigger in the "T" slot area than GI mags. You can't typically teach a new dog old tricks... Wait you can't use a new mag on an old gun. Link to comment Share on other sites More sharing options...
StooperZero Posted August 18, 2014 Report Share Posted August 18, 2014 i noticed the difference too.I use mostly GI mags in my auto-ord SBR but came across a new kahr mag in a trade. was very very tight. nothing a few seconds in the mill couldnt fix. Link to comment Share on other sites More sharing options...
OhioLarry Posted August 24, 2014 Author Report Share Posted August 24, 2014 i noticed the difference too.I use mostly GI mags in my auto-ord SBR but came across a new kahr mag in a trade. was very very tight. nothing a few seconds in the mill couldnt fix.The only mill I have turns pepper-corns into pepper. Link to comment Share on other sites More sharing options...
OhioLarry Posted September 17, 2014 Author Report Share Posted September 17, 2014 I fired a 30-round mag (no jams) today ventilating my new burn barrel. Bolt locked open after last shot. Sometimes problems just go away. Link to comment Share on other sites More sharing options...
Raining Brass Posted September 17, 2014 Report Share Posted September 17, 2014 Glad it "fixed itself". That is the easiest kind of fix there is. Link to comment Share on other sites More sharing options...
mnshooter Posted October 4, 2014 Report Share Posted October 4, 2014 (edited) If you really want to use a drum, it is possible to attach a portion of the spine from a GI mag (or use your pepper mill to make one from scratch) to a drum, and lock the drum in place the same as the stick mag. The drum will also need some of the horizontal slot material removed for clearance. The imported unmarked Crosby copy drums have a very good reputation, so would suggest starting with one of those. This is not terribly difficult, but would be very critical in positioning the magazine correctly, so if you don't feel like trying it yourself, Dan -"Deerslayer" has a lot of experience with this type of drum mod for his .22 conversion drums; you could ask him about building one. danblock@q.com It does seem like this is a lot of weight to hang on the mag catch, but you can find examples of people taping two 30 round mags together, which would weigh even more. Not saying this is the best idea; just that it can be done if you really want a drum. And, once again, the new production Kahr stick mags do not have the GI catch setup; they have a GI appearing round hole -that is positioned 1/10th higher than GI, so they can be used interchangeably with their earlier semi-auto modified (egg shaped hole) GI mags. Edited October 4, 2014 by mnshooter Link to comment Share on other sites More sharing options...
OhioLarry Posted October 9, 2014 Author Report Share Posted October 9, 2014 Thanks much for that additional information mnshooter! Link to comment Share on other sites More sharing options...
OhioLarry Posted October 9, 2014 Author Report Share Posted October 9, 2014 I bought this case for transporting the SBR, and am pleased with its quality at such a low price. Pouches too small for 30-round mag, but fine for 20's. Link to comment Share on other sites More sharing options...
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