Gun works...then doesn't work...any ideas?

[reconbob]

Hey Guys. I have an interesting situation here and you all are the experts.

 

A guy sent in a WH M1 Thompson in EXC condition. His complaint is that it

constantly jams. I think I am the second guy he has sent the gun to. The problem

is: we can;t get it to jam or malfunction in any way. For us it feeds, fires, and ejects

perfectly. We have tried with a 3 rounds in the mag, 15 rounds in the mag, and

30 rounds in the mag and all is well.

Now, the one thing we can't do here when we test fire is long bursts because

we can run off the bullet trap. We do 3 round bursts, and of course semi auto.

Over the last few years I have probably made close to 200 complete full auto

guns on our receivers. The standard test fire routine is one shot semi to verify

that the bolt will stay back and that the gun has enough power. Then put four

rounds in the mag, fire one semi, then three full auto. If this test works we ship

the gun. It would seem that this test is OK because I have never had a gun come

back or any complaint that a gun did not function properly.

Bearing all this in mind have any of you encountered a situation where a gun

works...then does't work...then works...etc.

There is no question the gun has not worked for the guy that sent it, but its

working now.

Your thoughts?

 

Bob

Edited February 28, 2019 by reconbob

[StrangeRanger]

Probably a silly question but have you verified the customer's ammo? Garbage in = garbage out (or not)

[ron_brock]

Operator error? How familiar is the customer with the gun? Ive seen guys hold the mag as a grip, light trigger pulls, jerk the gun and do some other funny stuff. The WH M1 usually works well.

 

Just asking maybe an obvious one, but could have been overlooked.

 

Same mags he used, youre using as well?

 

Ron

[Normal1959]

I have 3 and 2 of them are finicky with certain magazines. They go in the (no go) pile for future non use.

Works fine with other mags. One of my guns feeds any of the mags.

Eric

[ppgcowboy]

Did he send a few of the magazines that he uses with the gun.

[emmagee1917]

Yes , it is somewhat common in beltfed automatics . i've had a few 1917 / 1919 s do it . With these it is timing . If the timing is too fast or too slow the gun will function for 5-6-7 or so rounds and then stop . Recharge and it'll do it again . Now I view a full auto burst as a series of simi-auto shots , so I've never been able to wrap my head around this , but " constant Lamont " described it as a motor running with the timing moving one click per revolution then resetting back to correct when it dies .

As was said , more communication with the customer to see what exactly it was doing for him and a list of mags , ammo , etc. involved . It may be as simple as him switching to what you use in shop .

Chris

[huggytree]

Ive got a gun thats been to 2 gun smiths and it still jams. Not a Thompson. I think it has to be me? Then I hand it to a friend who owns FA. It jammed worse for him. I added a front vertical grip and the issues improved.

 

I may ship the gun back to the last smith and buy a plane ticket to shoot it with him. My suggestion? Have him fly to shoot it with you

Edited March 1, 2019 by huggytree

[mohawk64]

A guy that lives near me had a 1928 Savage and it would jam. Usually after 6-8 rounds. But it never jammed when I shot it. He was holding it like it was delicate. Limp wristing - he actually had the gun raise to the point of shooting holes in the drop ceiling at the indoor range. Looked like snow.

[Bob]

Bob, he may be shooting it like a target rifle. If so waiting for the break and reset the sear will drag on the bolt and slow it down. Have seen it at the shoots. Person shoots a few, jams, I try it and the mag goes empty. Might ask him if he pulls the trigger on and off with vigor. Good luck.

[Frank Iannamico]

Not a Thompson, but an UZI with a .22 subgun ord conversion.

One day it will run all ten mags without a single stoppage, next time out, gun cleaned, same mags, same ammo, won't fire 5 rounds without a stoppage.

Baffling.

[Motorcar]

light trigger pulls,

 

I'm in this corner too. I've had several individuals stop, start, stop, look at it funny, look at me like something was wrong with the gun..."mash that trigger to the floor and let it run!" They try to be too delicate with it.

[dalbert]

Bob,

 

I've had my WH M1 for 31 years now. For many years, I shot only cast lead, reloaded bullets through it. It functioned fine for all those years. When my time became more valuable, and I started buying FMJ ammo, it began to fail to feed pretty regularly. This plagued me for a few years, until PhilOhio looked at it, and told me I should change the barrel. I bought a PK barrel, installed, it, and it has run like a champion ever since. Apparently the WH barrel may have been cut to pistol specifications? The WH barrel was forgiving of the lead bullets, but the FMJ's evidently did not have enough malleability to feed into the tighter chamber.

 

Anyway, if it has its original barrel, you may want to take a look. My old WH barrel now serves on as a handle in Sig's Thompson barrel removal tool set, and helps to remove Colt barrels regularly, including when we removed Colt Chopper's barrel on what turned out to be Baby Face Nelson's Colt. So, it has a second life.

 

David Albert

dalbert@sturmgewehr.com

[Speeddemon02]

Get the issue caught on video somehow?

[jim c 351]

Bob,

Remember the time you sent 3 extractors to me that didn't work in any of your guns and all 3 worked perfectly in my M1???

Some things defy explanation.

Your customer needs to explain better what a JAM is. Failure to feed, failure to fire, failure to eject, all of the above??

Jim C

[deerslayer]

If it's got a West Hurley chamber.. That's your problem.. and.. Go outside somewhere.. Have a little fun pulling the trigger.. Bounce around a few cans..

[john]

Failure to feed or failure to extract causing the jams?

My old Numrich barrel that came on my '28 AO Bridgeport would stick one in the chamber hard but the chamber was worn to the point that this happened far enough forward so the pin failed to pop the primer. It took a few hard whacks then on the actuator to dislodge the cartridge.

I replaced the barrel with a fresh USGI Savage barrel and it runs like a champ now.

I'd go outside as Dan suggested and verify it on video with more than one mag as well as a good drum, then send it back with the video proof and some info on how to properly feed the gun.(as in "hot-enough" ammo.

G'luck!

[Normal1959]

Bob,

 

I've had my WH M1 for 31 years now. For many years, I shot only cast lead, reloaded bullets through it. It functioned fine for all those years. When my time became more valuable, and I started buying FMJ ammo, it began to fail to feed pretty regularly. This plagued me for a few years, until PhilOhio looked at it, and told me I should change the barrel. I bought a PK barrel, installed, it, and it has run like a champion ever since. Apparently the WH barrel may have been cut to pistol specifications? The WH barrel was forgiving of the lead bullets, but the FMJ's evidently did not have enough malleability to feed into the tighter chamber.

 

Anyway, if it has its original barrel, you may want to take a look. My old WH barrel now serves on as a handle in Sig's Thompson barrel removal tool set, and helps to remove Colt barrels regularly, including when we removed Colt Chopper's barrel on what turned out to be Baby Face Nelson's Colt. So, it has a second life.

 

David Albert

dalbert@sturmgewehr.com

 

Is there anyone who will change out 2 barrels for me? My one WH looks and acts new and never jams. The other 2 are pretty good after I changed all the guts but you can tell these have been well used and jam sometimes with certain mags.

I would love to have 2 new barrels put on them. I'm in Orlando Florida.

Eric

[timkel]

Maybe trigger technique? Check the bottom of the bolt for tell tail drag marks.

Tight chamber? There must be a gauge to check that.

Worn out barrel?

[Paladin601]

Bob,

Remember the time you sent 3 extractors to me that didn't work in any of your guns and all 3 worked perfectly in my M1???

Some things defy explanation.

Your customer needs to explain better what a JAM is. Failure to feed, failure to fire, failure to eject, all of the above??

Jim C

^^^^ This^^^^^

[DZelenka]

I have an MP40 that will shoot perfectly for some people and others cannot get it to fire at all. It is weird when a try and let someone shoot it and it goes clunck, Pull the bolt back and eject the round then it goes clunck again. Pull the bolt back and eject the round, hand it to me and I burn through the rest of the mag in a couple of bursts. It may just be how the person is holding the gun.

 

Dan

[Paladin601]

 

 

 

Could the spring possibly kinking and unkinking causing a binding in the bolt operation, I have seen this before, and replacing the spring properly solved the problem.

 

 

Also, I have seen different length spring guides for the M1

Edited March 1, 2019 by Paladin601

[dalbert]

 

 

 

Bob,

 

I've had my WH M1 for 31 years now. For many years, I shot only cast lead, reloaded bullets through it. It functioned fine for all those years. When my time became more valuable, and I started buying FMJ ammo, it began to fail to feed pretty regularly. This plagued me for a few years, until PhilOhio looked at it, and told me I should change the barrel. I bought a PK barrel, installed, it, and it has run like a champion ever since. Apparently the WH barrel may have been cut to pistol specifications? The WH barrel was forgiving of the lead bullets, but the FMJ's evidently did not have enough malleability to feed into the tighter chamber.

 

Anyway, if it has its original barrel, you may want to take a look. My old WH barrel now serves on as a handle in Sig's Thompson barrel removal tool set, and helps to remove Colt barrels regularly, including when we removed Colt Chopper's barrel on what turned out to be Baby Face Nelson's Colt. So, it has a second life.

 

David Albert

dalbert@sturmgewehr.com

Is there anyone who will change out 2 barrels for me? My one WH looks and acts new and never jams. The other 2 are pretty good after I changed all the guts but you can tell these have been well used and jam sometimes with certain mags.

I would love to have 2 new barrels put on them. I'm in Orlando Florida.

Eric

Eric,

 

What I'd suggest is for you to attend a show and shoot with The American Thompson Association this Summer. The tools would be available, and we could help you with the replacement.

 

David Albert

dalbert@sturmgewehr.com

[1921A]

Bob

 

David identified the main problem with the West Hurley M1s - pistol chambered barrel instead of the original mg spec - I believe it was actually a match pistol chamber.

 

The other problem I found was that the trigger frames were out of spec on most of the guns, specifically the position of the mag catch. It was positioned to low on the frame. Magazines would not feed properly unless you pushed upward while firing. The problem was more prevalent in automatic mode. They would fire 4-6 rounds and stop on an empty chamber. Changing to a GI barrel solved most of the problem. Changing to a GI trigger frame solved the rest of the problems.

 

Oddly, not all of these guns were like this but all of them I experienced were. PK could probably tell you a lot more about issues with them.

 

1921A

Edited March 2, 2019 by 1921A

[Rimcrew]

Being heavily involved in the pistol world, we often times ream a tight chamber, or a short chamber, to make a gun run reliably. Is there a reason a Thompson barrel cannot be reamed?

 

It's a simple and cheap fix.

Edited March 2, 2019 by Rimcrew

[deerslayer]

The Samsung Galaxy has a super slow motion video capture. I've used that to diagnose several guns that weren't working right.... Find one of those to help figure out problem guns is also advice I can offer beyond this post original question.