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Thompson 1928 WH ammo feed issue


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Hello

 

I am a new Thompson owner and seem to be having feeding issues with both the stick mags and the drum.

The results are always the same. Whenever the bolt pushes the round off a stick mag or drum, the round always seems to get stuck trying to feed into the barrel.

I have attached pictures to show what happens (here I am using dummy rounds but the results are the same with live ammo).

 

So far I have tried different stick mags and a different bolt with no luck.

I am looking for guidance on what could be the issue.

 

It used to be where I would have maybe 1 or 2 rounds jam like this, but now it is almost 99% of the time.

This is a Thompson 1928 WH.

Thank you

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Edited by mmetalfan
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Have you actually fired it yet? You might not have an issue.And if your riding the bolt closed hand cycling thats your problem.They dont like that.Also maybe a bad barrel.Is it a real original Thompson barrel or an aftermarket?There were some outof spec barrels being sold(a lot).Check for markings on the barrel last ring that meets the receiver Edited by Countryboy77
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Does it happen manually cycling it,as in you cycle it hard.

Most of the time yes. Even with first one it may jam like this. I just retried it with 5 dummy rounds, and the 1st round on the right side of mag failed to feed like in the pictures. The 2 rounds on the left side jammed at a strange angle trying to go into the barrel and the last 2 on the right side feed correctly. I did not have my hand on the actuator during these tests. Just released the bolt and let the spring decompress on its own.

 

 

Have you actually fired it yet? You might not have an issue.And if your riding the bolt closed hand cycling thats your problem.They dont like that.Also maybe a bad barrel.Is it a real original Thompson barrel or an aftermarket?There were some outof spec barrels being sold(a lot).Check for markings on the barrel last ring that meets the receiver

Yup. It used to fire okayish a few months ago (just decided to finally look into this issue now due to other priorities). To me it looks like ammo sometimes has a hard time riding up that ramp that helps to guide the ammo up into the chamber/barrel. As for the barrel I have not replaced it. To my knowledge it is original. Not seeing markings near the last ring or anywhere visible on the barrel.

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I would first disassemble the upper and closely examine the bolt, actuator, bronze lock, buffer guide, recoil spring, breech oiler, lock slots, etc. Check for signs of damage, cracked part(s), etc. Any West Hurley Manufactured Parts were marginal on their best day and should be replaced with USGI Parts. Edited by inertord
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I would first disassemble the upper and closely examine the bolt, actuator, bronze lock, buffer guide, recoil spring, breech oiler, lock slots, etc. Check for signs of damage, cracked part(s), etc. Any West Hurley Manufactured Parts were marginal on their best day and should be replaced with USGI Parts.

Will take a look and let you all know. Any good place you recommend for USGI parts? Also what parts would you recommend should be replaced?

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There's a good chance that the chamber is a bit undersized. When PK rebuilt my WH28, he rebarreled it with a ring sight barrel. However, he did rechamber and headspace the WH barrel and returned it as a spare. I think the undersized chamber of the WH barrel was partly responsible for a number of light primer hits my gun used to have. Since the rebuild, my WH functions flawlessly. If all else fails, you might consider having your barrel rechambered.

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Posted (edited)

There's a good chance that the chamber is a bit undersized. When PK rebuilt my WH28, he rebarreled it with a ring sight barrel. However, he did rechamber and headspace the WH barrel and returned it as a spare. I think the undersized chamber of the WH barrel was partly responsible for a number of light primer hits my gun used to have. Since the rebuild, my WH functions flawlessly. If all else fails, you might consider having your barrel rechambered.

Interesting you mention light primer strikes as I too was getting that before these current issues. Also what does PK stand for?

 

 

Any West Hurley Manufactured Parts should be replaced. Here is a great article and identification guide for these parts: https://smallarmsreview.com/those-west-hurley-thompson-parts/

Just finished reading. Excellent source of information. Probably a stupid question, but just to confirm, when he says GI parts, is he referring to parts that were used in the M1A1 thompson?

Edited by mmetalfan
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"Just finished reading. Excellent source of information. Probably a stupid question, but just to confirm, when he says GI parts, is he referring to parts that were used in the M1A1 thompson?"

 

 

M1928A1 parts, where appropriate. Some parts were common to and will fit both the M1/M1A1 and M1928A1. These include most or all of the parts in the frame, including the mag release.

 

Sounds like you're having typical WH teething problems. Many of these guns had the same symptoms and have been rebuilt by experts. They run fine today. I bought my own example from the original retail owner. It would not reliably fire three rounds. Sent it off to PK and he worked his magic with it. He did mention that among other problems, the feed ramp had apparently been attacked with a Dremel tool sometime after original manufacture. The damage was done by someone who didn't know what they were doing.

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This is a great article by Tom Davis about the WH TSMG parts and which ones should be replaced and why: https://smallarmsreview.com/those-west-hurley-thompson-parts/

 

Also, USGI parts are generally defined as parts that were produced to government specifications to meet the WW II war effort and they can be found for the M1928, M1 and M1A1. Some early WH TSMGs were built with surplus USGI parts, but that source eventually ran dry and AO began manufacturing their own again, but not up to the old standard from what I have read. I have used gunbroker to gradually stockpile USGI parts for the 1928 WH TSMG I am in the process of acquiring. Frank Iannamico's book, "American Thunder" has a very detailed chapter on TSMG parts and how to identify them.

 

Good luck!

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Is the mag catch US GI? If it isn't replace it with one, WH mag catches can be a problem.

No standard WH. In the smallarmsreview link, looks to be the bottom mag catch in the picture with the 3 types.

I attached some pictures of the upper internals of the rifle.

Does anyone have a good guide I can follow for taking out the parts of the lower such as the fire control and trigger etc?

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Is the mag catch US GI? If it isn't replace it with one, WH mag catches can be a problem.

 

Truly. Be sure you get a USGI mag catch with the drum magazine boss on it. Later M1 and M1A1 catches were redesigned and do not have this feature. They will not completely engage a drum.

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It appears at least 2 of the parts you show are USGI. The actuator looks like a Remington as indicated by the R mark. The hammer is a Stevens as indicated by the block S mark. Look over your other parts for small markings. A GI mag catch will have either a rounded S for Savage or a B for Gussack Mfg Co.

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mmetalfan,

 

Use the "Search" option for your topic. There are over two decades of incredible knowledge on this site free for you to use. You will probably find numerous WH feeding problems archived. There was much discussion about the feed ramp as well as the Blish ramp being machined wrong at WH. PK, mentioned above, has brought them back to original specs, Dan Block may be able to as well. At the top of the board there are pinned topics, Thompson FAQ: Check Here First is a great place to start. I am confident you will resolve the issue.

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I bet somone tried to modify the blish lock to compensate for the famous " west hurley wrong angle/ incorrect blish slots" that they got wrong so many times.Add photos of upper reciver underside whare blish lock cuts are.If you have a micrometer measure both sides from the bottom to where the blish ears ride.Also get a new buffer from pk that red fiber disk aint good no more.Do you have an oiler in it?
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mmetalfan,

Welcome to the Thompson forum. And congratulations on your 1928 West Hurley Thompson submachine gun. If you read my article in Small Arms Review magazine, you know that this variation was designed for the bottom of the Thompson market. Unfortunately, the 1986 machine gun ban drove the prices of WH Thompsons to an amazing level. That said, we can all be grateful there are around 3000 more Thompson guns in the marketplace.

 

All the advice you have received above is good advice. We have some very knowledgeable members on this forum. Do not panic. If all fails, Dan Block or deerslayer on this forum is pretty good at getting the West Hurley guns to run. Dan will not completely remanufacture one like PK at Diamond K Companies, but he can do some amazing things with a problem WH Thompson gun. His prices are very reasonable so keep that in mind. Unfortunately, PK is not accepting any new WHs for a complete overhaul. His backlog is probably at 3 years right now.

 

The most important internal part to inspect is the buffer pilot. If the buffer pilot does not have a "S" marked somewhere on the large round flange (usually on the flat but could be on the side of the flange) then do not shoot this Thompson. Period. Auto-Ordnance WH used two-piece buffer pilots that can and will separate. Guess what can fly out the back of the receiver when firing? Another excellent reason to always wear shooting glasses. If a WH buffer pilot, replace before shooing.

 

Looking at the other internals, it appears you have a cast WH actuator. The Blish lock and hammer look pretty beat up. Check the big end of the firing pin and see if it is flattened. Measure the length of the recoil spring. I believe 10.5 inches is the minimum length. Someone chime in if I am off on this. The hard buffer disk does need to be replaced with a modern polyurethane disk. This will help protect the rear of the receiver. I always recommend the discs from Diamond K Companies. These discs were priced under $10 apiece including shipping the last I checked.

 

It appears to me from just looking at the parts, your WH Thompson was really beating itself to death when firing. Changing out these parts may help.

 

Post a picture of the left side frame fire control levers and magazine catch. A WH magazine catch can cause all sorts of problems. Combine that with a worn WWII magazine and the issues double. Holding up on the magazine when firing can eliminate much of this problem so something to try when shooting. If the rocker pivot and safety levers are cast parts, these can be problematic too. I have seen WH safety levers move and engage the sear when firing and cause functioning problems. Needless to say, the frame needs to be disassembled to see what parts are included. Purple or plum colored parts are most likely WH parts.

 

The chambers on WH barrels are notorious for having out of spec chambers and can cause all sorts of problems. Keep that in mind (Dan can fix this).

 

If mine, I would replace all the WH parts with USGI parts, make sure the recoil spring is the proper length and obtain a polyurethane disc, clean and give it a go with factory ammo. If it is still a problem child, you may have to consider sending it to Dan. Whatever the problem, getting rid of the WH parts is always the first step.

 

Attached is a picture of West Hurley parts and modified parts removed from WH Thompson guns over the years in a display at the 2022 All Thompson Show & Shoot. If not a member of one of the Thompson Associations, this is also something to consider.

 

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I always recommend forum member Phil Askew for Thompson parts - philfordparts@yahoo.com. He usually has a good selection of NOS Thompson parts. New parts are always the best.

 

I have never purchased from APEX Gun Parts but the owner, Richard, is a regular on this forum. I have heard good things about his parts. You may have to use several sources to find everything you need.

 

I am sure other forum members will chime in with advice on disassembly of the frame and other part sources.

 

Good luck!

 

 

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PK is a very well known gunsmith for Thompsons. Sadly he is not going to do any new orders. He does however sell the buffer still. Contact him at p-k@q.com

 

My WH was milled too deep so it would runaway sometimes. I fixed it myself but it was a pain to figure out out and do a clean solution.

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Ryo,

I have heard that WH receivers being milled too deep is one of the major problems of the WH Thompson. I am curious as to how you remedied this situation. Thank you for posting his email address.

 

PK is no longer accepting WH Thompson guns for his complete re-manufacture process. That said, I understand he will do other work on Thompson guns, including WH guns, including barrel changes and installation of the Lyman adjustable rear sights. You will have to email him for his availability to perform such repairs. I also understand PKs reproduction Thompson barrels are first rate. If doing a barrel change, also replace a stamped grip mount (common on WH guns) with one of PK's milled grip mounts manufactured to GI specifications.

 

One area that is often overlooked with the WH Thompson is the buffer pilot hole in the rear of the receiver. Often times the hole is too large or not drilled perfectly straight. A loose-fitting buffer pilot can drag on a 1928 actuator when firing and cause reliability problems. PK can straighten the rear receiver hole, if necessary, and make a custom size buffer pilot to remedy this issue.

 

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TD,

Simple.. To fix the depth, I custom hand and cut and fitted a stainless steel spacer to put in it. The piece was too thick so I kept thinning it down. It runs and stops as it is suppose to now. Before semiauto was running like a full auto.

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