JEB007x Posted May 5 Report Share Posted May 5 Group, I hope I am posting in the correct Forum. I am a newbie to Thompsons. Attached are 2 pictures. It appears the front of the bolt has a slight Ridge very small but can feel with it with my fingernail. The opposing Sear? has the same sort of edge. You can see the wear on the lower. Should I replace the sear / bolt? I cannot feel it when I cycle the gun, (i have not shot it yet) Thanks in Advance. Link to comment Share on other sites More sharing options...
Motorcar Posted May 5 Report Share Posted May 5 Welcome and congrats on the M1. Yes you found the right forum. That is just a bunch of rounds and 80 years of being in that gun you see there. Firing open bolt and chugging like a freight train doesn't require the fine sear/trigger pull of a Camp Perry competition. You could dress it with a file if it bothers you, or replace both, but it wont change how the gun runs. There is no danger of it dropping out and firing inadvertently, that sear and bolt notch is huge by some comparisons. There might be a purist that says it must have new parts to be "right" but it's really not an issue. 1 Link to comment Share on other sites More sharing options...
JEB007x Posted May 5 Author Report Share Posted May 5 Motorcar... Thanks for the input. Glad there is no danger of it having fire inadvertantly. Will shoot as is!!! Thanks again. Link to comment Share on other sites More sharing options...
reconbob Posted May 6 Report Share Posted May 6 Thompson bolts and sears are very hard. Over Rockwell 60C. That is so hard a file will skid right off. While there is no danger here, I would stone the little ridges off so that the engaging surfaces stay smooth. At the minimum I would replace the sear, which might be $25. If you can afford it I would also replace the bolt. This wear is not normal. I have seen many many WW2 Thompsons that have many thousands of rounds thru them with the only wear being the loss of bluing. No deformation ridges as in your photo. In your first photo the loss of bluing on the trigger frame behind the sear is the result of the deformed ridge of the bolt scraping on the trigger frame which is not hardened and softer than the bolt. There is no way of knowing for sure why your bolt is deforming. Faulty heat treatment 80 years ago? Was the bolt exposed to heat somewhere along the way affecting its hardness? Another thing - when you shoot a Thompson you must fully and decisively pull the trigger. If you sloooowly pull the trigger to fire single shots the sear drags on the bottom of the bolt and the bolt will just nick the sear encouraging this deformation. If you want to fire single shots set the selector to single, and fully and decisively pull the trigger. Bob 1 Link to comment Share on other sites More sharing options...
TD. Posted May 6 Report Share Posted May 6 JEB007x, Welcome to the Thompson forum! Is your Thompson an Auto-Ordnance Corporation, West Hurley, New York, M1 Thompson submachine gun. Can you post complete picture of the underside of the bolt? Link to comment Share on other sites More sharing options...
Frank I. Posted May 6 Report Share Posted May 6 Quite common...too much semi-auto firing...its a MACHINE gun 😁 Link to comment Share on other sites More sharing options...
reconbob Posted May 6 Report Share Posted May 6 Frank - I respectfully disagree with you rating this bolt damage/deformation as "quite common". I have had hundreds of Thompsons thru my shop for builds or repairs and almost never see this deformation. Years back I processed 900 used, torched Thompsons (Sarco project. This was long before 1986 and they wanted to reweld/build them into guns). The bolts were torched but the sear notches were intact and there was thought of rebuilding them. None of the bolts had this damage/deformation. I have bought and sold hundreds of used bolts and this damage is so rare (if it is military bolt) as to not exist. I am willing to be educated/corrected. Anybody who reads this and is willing to take the time, check your Thompson bolt and let us know if it has the damage/deformation shown in the photo above. Bob/Phila Ordnance Link to comment Share on other sites More sharing options...
StrangeRanger Posted May 6 Report Share Posted May 6 (edited) If it's a WH gun it is not uncommon, my former WH 28 was almost exactly like that and the burr came off with a file no stoning required Edited May 6 by StrangeRanger typo Link to comment Share on other sites More sharing options...
Motorcar Posted May 6 Report Share Posted May 6 14 hours ago, reconbob said: Another thing - when you shoot a Thompson you must fully and decisively pull the trigger. If you sloooowly pull the trigger to fire single shots the sear drags on the bottom of the bolt and the bolt will just nick the sear encouraging this deformation. If you want to fire single shots set the selector to single, and fully and decisively pull the trigger. 3 hours ago, Frank I. said: Quite common...too much semi-auto firing...its a MACHINE gun 😁 1 hour ago, StrangeRanger said: my former WH 28 was almost exactly like that and the burr came off with a file no stoning required JEB007x, let us know how it runs. Link to comment Share on other sites More sharing options...
Motorcar Posted May 6 Report Share Posted May 6 Here is my 85 year old '28, it exhibits the same wear pattern as the one in question though not as pronounced. Pictures with such close in definition give a detail the human eye doesn't generally pick up on. I have put thousands of rounds thru this one, how many went before me? How many could have gone down range in 8 decades on any of these? Runs like a champ and I drive the trigger like a dump truck, no finesse. 2 Link to comment Share on other sites More sharing options...
laurencen Posted May 7 Report Share Posted May 7 any time you get deformation its worth stoning the burr, if left it will simply rub against another surface like the lower, the bolt is hard and will not clean up using a file, Im throwing it out the lower is not hardened to the same degree as the bolt if the burr is rubbing on the lower it will wear the lower over time Link to comment Share on other sites More sharing options...
Frank I. Posted May 7 Report Share Posted May 7 On 5/6/2026 at 12:34 PM, reconbob said: Frank - I respectfully disagree with you rating this bolt damage/deformation as "quite common". I have had hundreds of Thompsons thru my shop for builds or repairs and almost never see this deformation. Years back I processed 900 used, torched Thompsons (Sarco project. This was long before 1986 and they wanted to reweld/build them into guns). The bolts were torched but the sear notches were intact and there was thought of rebuilding them. None of the bolts had this damage/deformation. I have bought and sold hundreds of used bolts and this damage is so rare (if it is military bolt) as to not exist. I am willing to be educated/corrected. Anybody who reads this and is willing to take the time, check your Thompson bolt and let us know if it has the damage/deformation shown in the photo above. Bob/Phila Ordnance Hi Bob, Perhaps it's a case of civilian VS military use, as well as 80+ years of shooting as opposed to 20 or so years of military service? There is no doubt that you have observed many more Thompsons than I but, but I have seen burrs on the sear surface of the bolt that gouged the trigger frame. (as depicted in a photo in one of the threads above) When I bought my first Thompson, a knowledgeable and respected enthusiast advised me to watch for 1. dress burrs on the bottom of the bolt, 2. always hold the button down when installing and removing a '21 or '28 buttstock assy and 3. always wipe down rear part of the grip where the web of your hand touches. Respectfully, Frank Link to comment Share on other sites More sharing options...
JEB007x Posted May 10 Author Report Share Posted May 10 Gents, Thank you for all the feedback. I have not checked the forum as I was away visiting my Mom! I am always getting spare parts so I have picked up an M1 and M1A1 bolt. Need to get a sear. I will probably fire her as is, very soon. I am going to submit several other photos and would love general feedback on your observations on the overall condition. Most is S, savage marked. Thanks.. this fourm is very helpful. John Link to comment Share on other sites More sharing options...
JEB007x Posted May 10 Author Report Share Posted May 10 On 5/6/2026 at 9:19 AM, TD. said: JEB007x, Welcome to the Thompson forum! Is your Thompson an Auto-Ordnance Corporation, West Hurley, New York, M1 Thompson submachine gun. Can you post complete picture of the underside of the bolt? Auto Ordinance Link to comment Share on other sites More sharing options...
rpbcps Posted May 11 Report Share Posted May 11 (edited) Could this be a mismatched M1? A subtle difference between AOC and Savage produced weapons is found on the trigger frame. The selectors on Auto-Ordnance Corporation Bridgeport produced Thompsons are marked, ‘full auto’ on one single line, while on Savage manufactured Thompsons, ‘full auto’ are stamped in two lines, if I recall correctly? If I am reading the AIO stamp on the receiver correctly, I see 'GHD'. Those being the initials of Colonel Guy H. Drewery, who was the AIO at the Auto-Ordnance Bridgeport plant. Edited May 11 by rpbcps Typo Link to comment Share on other sites More sharing options...
rpbcps Posted May 11 Report Share Posted May 11 Just remembered, this topic is in the reference thread pinned post. www.machinegunboards.com/forums/index.php?/topic/20691-identifying-savage-and-auto-ordnance-bridgeport-manufactured-thompsons Link to comment Share on other sites More sharing options...
JEB007x Posted May 11 Author Report Share Posted May 11 7 hours ago, rpbcps said: Could this be a mismatched M1? A subtle difference between AOC and Savage produced weapons is found on the trigger frame. The selectors on Auto-Ordnance Corporation Bridgeport produced Thompsons are marked, ‘full auto’ on one single line, while on Savage manufactured Thompsons, ‘full auto’ are stamped in two lines, if I recall correctly? If I am reading the AIO stamp on the receiver correctly, I see 'GHD'. Those being the initials of Colonel Guy H. Drewery, who was the AIO at the Auto-Ordnance Bridgeport plant. When you say mismatched, do you mean re-weld? The link you sent is very helpful. The left side of the receiver has all the markings of Savage (correct me if I am wrong), Per the link, I have FJA, GEG (in a circle), two lines for full / auto and NO. vs No. before the serial number. I do not see GHD. I also see a heat treated line behind the ejector. Much like 1911's where the front and around the muzzle end and slide stop notch. Opinions?? PS I am going to save the markings link you have. It is very helpful Link to comment Share on other sites More sharing options...
TD. Posted May 11 Report Share Posted May 11 JEB007x, It appears you have a very nice example of a M1 Thompson submachine gun. This variation is not my specialty but others on this forum are very knowledgeable. If you do not already have a copy, I highly recommend, American Thunder, Third Edition, by Frank Iannamico. It is a steal at 40 bucks on Amazon.com. I can say the bolt you pictured is not an Auto-Ordnance West Hurley, New York bolt (good news). I have found the best place for parts is Board member Phil Askew. He has a very nice selection of NOS parts. Phil can be reached via PM on the Board or by emailing him at: philfordparts@yahoo.com Phil will be at The American Thompson Association Show & Shoot later this year. Another reason not to miss this event. 2 Link to comment Share on other sites More sharing options...
rpbcps Posted May 11 Report Share Posted May 11 3 hours ago, JEB007x said: When you say mismatched, do you mean re-weld? The link you sent is very helpful. The left side of the receiver has all the markings of Savage (correct me if I am wrong), Per the link, I have FJA, GEG (in a circle), two lines for full / auto and NO. vs No. before the serial number. I do not see GHD. I also see a heat treated line behind the ejector. Much like 1911's where the front and around the muzzle end and slide stop notch. Opinions?? PS I am going to save the markings link you have. It is very helpful Mis-matched for us in UK is trigger frame and the receiver from two diffrent guns. Something common amongst former British and Commonwealth Thompsons. My mistake, if not GHD marked, photo, (or is it eyes), was not the best. Matching Savage Thompson, as you say. Link to comment Share on other sites More sharing options...
gijive Posted May 11 Report Share Posted May 11 Looks like JEB007x has a Savage made Thompson, not an Auto-Ordnance. See below picture: Link to comment Share on other sites More sharing options...
JEB007x Posted May 12 Author Report Share Posted May 12 On 5/7/2026 at 1:11 PM, laurencen said: any time you get deformation its worth stoning the burr, if left it will simply rub against another surface like the lower, the bolt is hard and will not clean up using a file, Im throwing it out the lower is not hardened to the same degree as the bolt if the burr is rubbing on the lower it will wear the lower over time Can you enlighten me on "stoning", vs file...exactly what tool is that? Thanks John Link to comment Share on other sites More sharing options...
shadycon Posted May 13 Report Share Posted May 13 https://www.grainger.com/product/1RDD5?gucid=N:N:FPL:Free:GGL:CSM-1946:tew63h3:20501231 1 Link to comment Share on other sites More sharing options...
JEB007x Posted May 14 Author Report Share Posted May 14 Update, I ran 90 rounds of Blazer and 90 of Magtech. Gun functioned flawlessly. No issues. Thanks for all the help. I am going to stone down the burr just a bit anyway. Thanks again for all the information and knowledge..JB Link to comment Share on other sites More sharing options...
Motorcar Posted Friday at 08:04 PM Report Share Posted Friday at 08:04 PM On 5/14/2026 at 1:36 PM, JEB007x said: Gun functioned flawlessly. No issues. Great, thanks for the update and not letting the thread die unanswered. 1 Link to comment Share on other sites More sharing options...
laurencen Posted Tuesday at 08:05 PM Report Share Posted Tuesday at 08:05 PM On 5/12/2026 at 10:52 AM, JEB007x said: Can you enlighten me on "stoning", vs file...exactly what tool is that? Thanks John stoning is using a good flat stone, lay the item on the stone and just like filing move the work over the stone typically in a figure 8 to remove the burr, do not apply much downward pressure let the stone do the work. used this process many times on motor blocks and heads to clean them up also for machine parts removing marks from cutters Link to comment Share on other sites More sharing options...
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