jonnyjon88 Posted April 1 Report Share Posted April 1 All, I have a WH M1 thompson that came with a loose grip mount (1/2” milled). Loose as in, it has noticeable play where the grip mount slides into the receiver and causes the whole forend to be wobbly. I sent the gun off to a guy to do some work on it, and one of the things to address was this loose mount. When i got it back, i could see that he replaced the grip mount with the riveted kind, but it was tight so i was fine with it. Well after a couple hundred rounds it worked itself loose again. I then purchased a thompson barrel removal tool, removed the barrel and the grip mount, and could see where he had peened the edges of the riveted mount to make it fit tight. So i then replaced it with a brand new milled mount from waffenmeisters. This mount also fit loose, so I just slapped a barrel band on it and kept shooting. However, i prefer the clean look of the barrel with no band, and also like to know that everything is tight like it should be (if it should be). So with all this being said my questions are as follows: Are Thompson grip mounts supposed to stay tight throughout their life on the gun, or do they all eventually shoot loose? Is there a better way to make a tight fit besides peening the grip mount edges? What is the life expectancy (round count) of a West Hurley receiver? Thanks for any insight yall can provide! Link to comment Share on other sites More sharing options...
robbo Posted April 2 Report Share Posted April 2 I guess I'll be first to reply as best I can. #1 Grip mounts should always stay tight and never loosen. #2 Well, its a Westie receiver so the mount slot was probably not machined correctly. Modify the grip mount bar. Maybe build up weld on the bar to make it bigger and fit it to the slot. Someone else here may have a better idea. #3 My Westie 28 had well over 100k rounds before PK worked his magic on it. YMMV. Link to comment Share on other sites More sharing options...
robbo Posted April 2 Report Share Posted April 2 Oh, and another thing, I once saw a 28 with a loose grip mount that was "fixed" by drilling a hole through it and into the receiver, then putting a set screw with locktite in it. Seemed to be OK. Its a Westie, I don't think you'll hurt it. Link to comment Share on other sites More sharing options...
reconbob Posted April 2 Report Share Posted April 2 The T-slot for the grip mount is too big. If it was me I would put plastic steel epoxy in the T-slot, plug in the grip mount, tighten the barrel, and wipe off the excess epoxy. The grip mount will no longer rattle and you are not welding, peening, altering anything. Bob 1 Link to comment Share on other sites More sharing options...
StrangeRanger Posted April 2 Report Share Posted April 2 If you epoxy it in place WAX THE GRIP MOUNT before you insert it or you'll never be able to remove it. Grip mounts actually are a service part. The tiny lug that rides on the barrel shoulder does break so the mount needs to be replaceable 1 Link to comment Share on other sites More sharing options...
jonnyjon88 Posted April 2 Author Report Share Posted April 2 Guys, thanks for the replies so far. Im thinking devcon? Or is there a specific one i should use? Yes I will definitely use a release agent if i go this route Link to comment Share on other sites More sharing options...
reconbob Posted April 2 Report Share Posted April 2 (edited) I don’t know that the grip mount was ever designed/intended to be replaced . I have probably removed 100’s of grip mounts from receivers. To get the grip mount off, you have to get the barrel off. As recently discussed many barrels require excessive force to remove. Probably 1/3 of grip mounts require a special Doug Richardson slide hammer where the grip mount is clamped and hammered out. You sometimes have to slide the slide hammer 10+ times as hard as you can to get the grip mount to break free and start to move and it might only move 0.015” per strike and have to be hammered off all the way. If you tried to do it by clamping the grip mount and using a brass block on the fragile/thin face of the receiver you will damage/bend/deform it. Also as discussed while all this is being done the grip mount has to be flexed away from the barrel or it will snap into the gaps between the fins. May be I missed it but I never seen use or reference to any of these tools in any service manual. I have never encountered a Springfield, Carbine, Garand, M1917 rifle, or BAR that had a barrel as tight and difficult to break free and remove as a Thompson barrel. Go with the Devcon and should the future require replacement the grip mount will be no more difficult to remove than a tight original one. Bob Edited April 2 by reconbob Link to comment Share on other sites More sharing options...
TSMGguy Posted April 2 Report Share Posted April 2 Send the gun to a pro for replacement of the grip mount. You'll be glad you did. True, the gun is "only" a WH, but it's still deserving of respect in its own way. I had PK sort through my own WH M1 and am very glad I did. He replaced the original WH grip mount with one of his own manufacture. The gun has been perfect since. Link to comment Share on other sites More sharing options...
TD. Posted April 2 Report Share Posted April 2 I am with TSMGguy on this issue; send your West Hurley to Board member PK and let him replace the grip mount with one of his. While PK is not accepting any more West Hurley guns for re-manufacture, he is still working and does small jobs like this. His work is impeccable. All machine guns on the Registry are valuable and deserve the upmost care. I also recommend examining the bolt in your M1A1 West Hurley for a manufacturer mark. If the bolt is not marked, it is probably a West Hurley bolt. If so, the bolt was not manufactured to USGI specifications and can cause functioning problems. I have heard these West Hurley M1A1 bolts tend to wear quickly. Another check is an oval (instead of the standard rectangular) rocker pocket on the bottom of the bolt. Link to comment Share on other sites More sharing options...
jonnyjon88 Posted April 2 Author Report Share Posted April 2 Thanks again for the suggestions. I will reach out to PK before going devcon route, never hurts to cover all the bases. As far as the bolt goes, I replaced the m1a1 style bolt with a (savage?) m1 bolt as soon as i received the gun, just to be extra safe in case of OOB detonation. Link to comment Share on other sites More sharing options...
Doug Quaid Posted April 13 Report Share Posted April 13 I found a USGI barrel band for my WWII M1A1 and installed it. It changes the USGI riveted mount system from being kind of weak to practically indestructible. So I don't have to worry about it anymore. West Hurleys are like Vector UZIs. They have little "historic" collector value, but they're still a $20,000 gun. So I say do things right. If I was in your shoes, I would have the mount replaced with a better one, keep the barrel band on and call it good. Might as well get a USGI barrel installed while you're at it. The barrel band is a legitimate WWII item that was in widespread use by the military, so it's not like you're harming the historic look of the gun by using the barrel band. Link to comment Share on other sites More sharing options...
Doug Quaid Posted April 13 Report Share Posted April 13 On 4/2/2025 at 8:22 AM, reconbob said: I don’t know that the grip mount was ever designed/intended to be replaced . I have probably removed 100’s of grip mounts from receivers. To get the grip mount off, you have to get the barrel off. As recently discussed many barrels require excessive force to remove. Probably 1/3 of grip mounts require a special Doug Richardson slide hammer where the grip mount is clamped and hammered out. You sometimes have to slide the slide hammer 10+ times as hard as you can to get the grip mount to break free and start to move and it might only move 0.015” per strike and have to be hammered off all the way. If you tried to do it by clamping the grip mount and using a brass block on the fragile/thin face of the receiver you will damage/bend/deform it. Also as discussed while all this is being done the grip mount has to be flexed away from the barrel or it will snap into the gaps between the fins. May be I missed it but I never seen use or reference to any of these tools in any service manual. I have never encountered a Springfield, Carbine, Garand, M1917 rifle, or BAR that had a barrel as tight and difficult to break free and remove as a Thompson barrel. Go with the Devcon and should the future require replacement the grip mount will be no more difficult to remove than a tight original one. Bob As a bona-fide redneck, basically everything I owned until about 5 years ago had some kind of epoxy repair. Some epoxy is kind of soft and elastic, but some is really hard. If you prep the surfaces properly, and the coat of epoxy between the surfaces is thin, it can be amazingly hard to break the bond free. To the extent that the glue is stronger than the parts. I would be really leery about using JB Weld to fasten a part that slides tightly into another part. If I was going to do that, I would get a top quality ordnance steel mount, and then use the barrel band as well. That way I would be more or less guaranteed to not ever have try to remove it. Just curious, have you ever smacked a glued mount loose with your removal tool? How did it go? Link to comment Share on other sites More sharing options...
jonnyjon88 Posted April 14 Author Report Share Posted April 14 I have decided to forego the epoxy, and have shipped the gun off to PK, as there were a couple other minor (hopefully) issues i would like an expert to address as well. Link to comment Share on other sites More sharing options...
TSMGguy Posted April 14 Report Share Posted April 14 13 hours ago, jonnyjon88 said: I have decided to forego the epoxy, and have shipped the gun off to PK, as there were a couple other minor (hopefully) issues i would like an expert to address as well. Good move! Link to comment Share on other sites More sharing options...
Countryboy77 Posted April 18 Report Share Posted April 18 Probly had a big ol 3/4" popsicle stick hangar at 1 time. I would put a cote of PVA on the waffenmeisters bracket and jb weld it in placecarefully keeping it out of barrel threads.glue without barrel.When it dries the pva will allow you to knock it loose but it will still be tight. Clean up with sandpaper and screw in barrel and mount .Done.the jb weld will stick to inside of front of receiver and not to the mount bar. Link to comment Share on other sites More sharing options...
Doug Quaid Posted April 19 Report Share Posted April 19 On 4/13/2025 at 9:01 PM, jonnyjon88 said: I have decided to forego the epoxy, and have shipped the gun off to PK, as there were a couple other minor (hopefully) issues i would like an expert to address as well. They say that westie barrels have bad chamber dimensions sometimes might want to have that checked while the barrel is off the gun 1 Link to comment Share on other sites More sharing options...
TD. Posted April 20 Report Share Posted April 20 jonnyjon88, An excellent decision. I agree with Doug Quaid, above. Have PK. check the chamber dimensions. I understand this is an easy fix for a Thompson smith. Link to comment Share on other sites More sharing options...
jonnyjon88 Posted April 20 Author Report Share Posted April 20 Guys thanks for the suggestion, I will bring that up next time I hear from him. I think I will thank myself later, for deciding to send it off to the master! Link to comment Share on other sites More sharing options...
Mk VII Posted April 20 Report Share Posted April 20 Somebody tried centre-punching this one, presumably to tighten it up Link to comment Share on other sites More sharing options...
jonnyjon88 Posted April 21 Author Report Share Posted April 21 Mk VII, what is the purpose of that notch, or cut, in your receiver behind the grip mount? Link to comment Share on other sites More sharing options...
Canuck Posted April 21 Report Share Posted April 21 My guess it is a deactivated gun and that cut was part of the process at the time. Link to comment Share on other sites More sharing options...
jonnyjon88 Posted June 10 Author Report Share Posted June 10 Just wanted to follow up on this and let everyone know, I got my gun back from PK and ran some mags thru it, and have handled it a good bit at this point. All i can say is WOW! I did not realize how much better my thompson could be. Everything nice and tight now. Thanks everyone for suggestions! 1 Link to comment Share on other sites More sharing options...
Motorcar Posted June 10 Report Share Posted June 10 Thanks for posting your results. Dead end threads are frustrating for others looking for solutions. Glad it got resolved for you! Link to comment Share on other sites More sharing options...
MauserMatt Posted June 10 Report Share Posted June 10 6 hours ago, jonnyjon88 said: Just wanted to follow up on this and let everyone know, I got my gun back from PK and ran some mags thru it, and have handled it a good bit at this point. All i can say is WOW! I did not realize how much better my thompson could be. Everything nice and tight now. Thanks everyone for suggestions! Very glad to hear! How did you ship your Thompson? My Savage M1 needs to be repaired in the same way (it has an M1A1 riveted type grip mount) as it has wobbled for years. But I'm scared to death to send my Thompson in the mail... Link to comment Share on other sites More sharing options...
jonnyjon88 Posted 17 hours ago Author Report Share Posted 17 hours ago Yes it is nerve wracking, I sent mine via USPS registered mail and threw an apple air tag in the box so I could watch its travel in real time. Apparently with registered mail it is secured behind lock and key and can only be handled by certain individuals. Link to comment Share on other sites More sharing options...
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