coastie70 Posted March 1, 2018 Author Report Share Posted March 1, 2018 coastie,OK, so you have done the one round test multiple times and the bolt always failed to lock all the way to the rear, correct???I guess it could be something as simple as a overly strong, non original, bolt spring. Like a Wolfe spring. Or a weak sear spring.Perhaps the sear trip installed backwards or damaged.Perhaps you live near a forum member who could inspect your gun.While waiting for a volunteer, buy a GI bolt and sear spring.Jim CJim,Thanks. Bolt never has locked fully to the rear. I replaced recoil spring. It was the same length as new GI spring. Next step is to replace sear spring. Trip appears correct.Bill Link to comment Share on other sites More sharing options...
jim c 351 Posted March 1, 2018 Report Share Posted March 1, 2018 Bill,I fear we may be back to the earlier mentioned shot out barrel issue.You need the help of a local Thompson collector.Jim C Link to comment Share on other sites More sharing options...
Petroleum 1 Posted March 1, 2018 Report Share Posted March 1, 2018 What does the seller have to say about this?? Were you told up front the M1 has issues?? Link to comment Share on other sites More sharing options...
coastie70 Posted March 2, 2018 Author Report Share Posted March 2, 2018 Bill,I fear we may be back to the earlier mentioned shot out barrel issue.You need the help of a local Thompson collector.Jim CI think you are correct. I just realized it's sometimes keyholing some shots. Link to comment Share on other sites More sharing options...
taeelec Posted March 2, 2018 Report Share Posted March 2, 2018 I agree with Jim C about your M1 having a shot out barrel. Key holing is a dead giveaway to a worn out barrel. Todd in Oregon Link to comment Share on other sites More sharing options...
Sandman1957 Posted March 2, 2018 Report Share Posted March 2, 2018 Bill, sent you a PM with name and number of someone fairly local to you who can take of this for you. Let me know how it works out. CheersSteve Link to comment Share on other sites More sharing options...
huggytree Posted March 2, 2018 Report Share Posted March 2, 2018 if you bought it from one of the larger national dealers they should pay to fix this for you... most sellers of FA on any business level would help you out to some degree or pay for the repair if bought AS IS from a local then you'd be on your own.... contact Reconbob to see if he has any barrels for sale...he sold me a few that are minty for a very reasonable price a few years ago...... kinda crazy to wear out a barrel....someone really enjoyed that thompson or did a lot of mag dumps and heated that barrel up nicely and wore it down Link to comment Share on other sites More sharing options...
wwiifirearms Posted March 3, 2018 Report Share Posted March 3, 2018 Keyholes could also mean under powered.Counter intuitive, but a week recoil spring could prevent enough pressure from building, so maybe not too heavy a spring, could be too light. Also, if you havent tried several other brands of ammo, do that just to be sure. What area are you located in, maybe someone near you can bring another gun to compare, maybe swap lowers just to test. Link to comment Share on other sites More sharing options...
ppgcowboy Posted March 3, 2018 Report Share Posted March 3, 2018 Have you slugged the barrel? Do it, mike the lead slug and see what it looks like. Use pure lead bullets and a wooden dowel. Link to comment Share on other sites More sharing options...
Petroleum 1 Posted March 3, 2018 Report Share Posted March 3, 2018 Have you slugged the barrel? Do it, mike the lead slug and see what it looks like. Use pure lead bullets and a wooden dowel.Can you explain ? Tia Link to comment Share on other sites More sharing options...
shadycon Posted March 3, 2018 Report Share Posted March 3, 2018 Push a lead slug thru the barrel and measure it! This will tell you what the internal measurement is of the bore! Link to comment Share on other sites More sharing options...
Petroleum 1 Posted March 3, 2018 Report Share Posted March 3, 2018 Push a lead slug thru the barrel and measure it! This will tell you what the internal measurement is of the bore!A .45acp lead bullet or some sort of custom made slug? Link to comment Share on other sites More sharing options...
shadycon Posted March 3, 2018 Report Share Posted March 3, 2018 Doesn't matter as long as it is soft lead and the correct diameter of a .45 slug to start with. Link to comment Share on other sites More sharing options...
Mk VII Posted March 4, 2018 Report Share Posted March 4, 2018 muzzleloader ball would do. Link to comment Share on other sites More sharing options...
Petroleum 1 Posted March 4, 2018 Report Share Posted March 4, 2018 So an in spec barrel would be snug around the lead slug?? Anything loose fitting the barrel is kaput? Link to comment Share on other sites More sharing options...
95mustang Posted March 4, 2018 Report Share Posted March 4, 2018 (edited) what you are doing is pounding a pc of lead into the bore so you can measure it with a micrometer if you get .444 you are on the high side of the tolerance for a tommy gun barrelif you see .452 you have a shotgun barrel with little to no rifling left . so anything near the rifling dimension at the breech end is going to cause pressure loss from behind the bullet you can't seal the bore if it's worn out bigger than the average 45 caliber slug at 451 that measly little .oo4 a side is very important to keep the gas behind the bulletfor reference a piece of paper averages about .005 thick Edited March 4, 2018 by 95mustang Link to comment Share on other sites More sharing options...
ppgcowboy Posted March 6, 2018 Report Share Posted March 6, 2018 The lead will slide pretty easy. Get a few pure lead cast .452 bullets and push them through the barrel. You should get a good read of the condition of the lands and grooves. Put a micrometer and measure the diameter. This should confirm if the barrel is shot out. The previous posts explained it well. Doing this does not harm a barrel. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now