Failure to Fire

[zeeone]

Ever since I obtained my '96 WH, I have experienced a problem where it will fire the first round but will not fire following rounds although they feed into the barrel, the bolt is fully closed as far as I can tell, and the firing pin does fire. I thought it might be the extractor preventing the bolt from fully closing but I carefully examined it when I tore the gun apart (extractor is fine) and it extracts the fired and unfired rounds fine. Looking closely at the primer, in each case of the unfired round I can see under a magnifying glass an extremely slight indentation on the primer. I tried to take pictures of the primers but could not get the camera to focus that closely.

 

Yesterday, it failed to fire on the first round so I switched magazines and on the second mag it fired the first 3 rounds before not firing. A friend suggested switching from Federal so I picked up Winchester and these were the rounds I used yesterday with the same poor result.

 

Another suggested that the gun needs cleaning but I obtained the AGI video and followed their procedure several times but with the same problem at the range.

 

My uneducated guess is that it may be the firing pin and if so, I looked for a replacement. Numrich lists Types I, II, III, IV. the first three of which are out of stock. I do not know what design they reference but all I know is that I have the long tip. AO does list a long tip on their site and was wondering if anyone can advise if that will fit my older gun.

 

On the other hand, it may be a component such as a weak firing spring. I do not have the experience to know and will greatly appreciate you comments to this aggravating problem.

 

Thanks.

[Chief762]

zeeone,

Is this a full auto or semi auto only gun? OK, my bad, semi forum.

 

Chief

Ever since I obtained my '96 WH, I have experienced a problem where it will fire the first round but will not fire following rounds although they feed into the barrel, the bolt is fully closed as far as I can tell, and the firing pin does fire. I thought it might be the extractor preventing the bolt from fully closing but I carefully examined it when I tore the gun apart (extractor is fine) and it extracts the fired and unfired rounds fine. Looking closely at the primer, in each case of the unfired round I can see under a magnifying glass an extremely slight indentation on the primer. I tried to take pictures of the primers but could not get the camera to focus that closely.

 

Yesterday, it failed to fire on the first round so I switched magazines and on the second mag it fired the first 3 rounds before not firing. A friend suggested switching from Federal so I picked up Winchester and these were the rounds I used yesterday with the same poor result.

 

Another suggested that the gun needs cleaning but I obtained the AGI video and followed their procedure several times but with the same problem at the range.

 

My uneducated guess is that it may be the firing pin and if so, I looked for a replacement. Numrich lists Types I, II, III, IV. the first three of which are out of stock. I do not know what design they reference but all I know is that I have the long tip. AO does list a long tip on their site and was wondering if anyone can advise if that will fit my older gun.

 

On the other hand, it may be a component such as a weak firing spring. I do not have the experience to know and will greatly appreciate you comments to this aggravating problem.

 

Thanks.

Edited July 16, 2013 by Chief762

[Ding]

look at the extractor(engaged in the bolt),it may be protruding a little further forward from the bolt face thus causing it to not close fully.Tap it backwards,if it moves flush to the bolt face you may need a new extractor.On your firing pin contacting your primers,are they deep and have a "square indentation " on the primers?.Is the firing pin retaining roll pin bent or broke.?.

I am going through some issues myself with a first round firing and the second round jamming.

 

Did you put the hammer block pin in first or is it in at all after cleaning it,is the firing pin tip in one piece,no chip or broken.? just thinkin out loud here.

[zeeone]

Ding,

Thanks for the comments. I pulled the gun apart to examine the extractor and found it slightly above the bolt face. the top of the extractor extends slightly above the rim above the bolt face. The firing pin retainer pin is fine. However, in examining a spent case I noticed a deep round indentation on the primer as the end of my firing pin is round and not square.

 

Initially I did have some problems with feeding but they were resolved with repair of the mag. It appears that all the rounds that did not fire were fully inserted in the barrel and contacted by the bolt as they extracted normally when the bolt was pulled back.

 

Unfortunately I am not familiar enought with the components to know if one is worn to the point of malfunction. Thus your comments are important.

 

Thanks.

[Ding]

It doesn't sound as though your firing pin is the issue.What I meant is on the "square part" was the firing pin will make it's mark on the primer BUT the "square" part is the base of the firing pin,where the firing pin end is extending into the primer,thus leaving a square mark on the primer plus the round mark of the firing pin tip.It is easy to remove/replace the extractor FWIW.Are you getting the recoil spring guide "U" in the firing pin pilot slot.(on the rear of the receiver there is a button,if you push it it will spring in and back out under tension of the spring if it is in correctly) Sometimes things can be missed when assembling.Maybe the firing pin pilot has a burr that causes the spring to stick or the extractor may have something under it.Could be something (piece of brass,dirt etc) stuck inside the lower that is causing a certain part or spring from doing it's job.Just a suggestion here.Take the pistol grip off the lower and use a spray cleaner to clean/clear the lower of anything that maybe be in there,re-oil everything again and try it out.Again these are just trouble shooting ideas.

What did you do to fix your feeding issues on the mags,open the lips up,close them or work the hole over,if ya don't mind me asking.

[james m]

A common problem with Thompson's that I discovered when I was maintaining these on a regular basis as rentals is a buildup in the extractor channel. The round would apparently chamber ok but you'd invariably notice a light primer hit and failure to fire. I'd recommend you field strip your gun and get in there and thoroughly clean out the extractor channel and see if this helps before trying anything else.

Jim

[wh20crazy]

Does your trigger feel right on the fail to fires? If not, push it forward. If it clicks, then works normally you may have to disassemble the trigger group to clean & lubricate it. Mine was not resetting. I could either push the trigger forward to reset it, or make sure I let it snap forward after firing. A good, thorough cleaning fixed it.

[zeeone]

Finally got around to pulling the gun apart again. Pulled the extractor and the slot and extractor were clean as a whistle.

There is only the indentation of the firing pin on those primers it does contact...no square indentation. In fact, the part behind the pin is oval, not square. Perhaps this is the problem (wrong firing pin?).

The trigger is fine and does not hang up. A good solid click.

I've taken it apart several times now and all the springs are in their correct places and not hanging up. I will take it to the range again Friday hoping for some reason it will work. If not, I will contact Phila. Ordinance (I live about 30 minutes away) and see if he will look at it or if not, perhaps he can recommend a local gunsmith as I am at my wits end. Maybe all it needs is a knowledgeable person who can pick out the problem right away.

 

Thanks for all of your comments. Lets hope they did the trick when I go to the range Friday.

 

Rich

PS: Don't remember what I did to get the lips of the mag to properly relase the round. I have a bunch of mags and perhaps found two that work (One is Seymour and the other Khar). I do recall using laping compound on the rails of one to get it to slide on/off easier

Edited July 25, 2013 by zeeone

[Ding]

May have some brass or other foreign object blocking or gumming up the firing pin channel,maybe even a burr on the firing pin that doesn't allow it to engage properly at times.The extractor channel in clean and clear.Did ya check the extractor for chips or burrs on it's lip and does the extractor sit flush in the extractor channel the whole length.They get bent,develope a "hump" midway in the length of it.Sometimes,if it isn't lubed up,bolt,firing internals etc it will cause this malfunction,new magazines/springs will slow down the bolt,and if the extractor doesn't close fully over the casing it will cause this issue also,if it is dirty/gummed up (which you cleaned).I would at least lube it well then try to reproduce the issue again.May be just a lube,or lack of enough lube issue. just a thought.

[pistolpete59]

Hi there,

Did you ever find out why it would fail to fire.

I am experiencing the same problem and can not figure it out.I load a stick magazine the first 3 rounds fired no problem the fourth was chambered but there was no click I'm thinking the trigger group is no correct and I could not push trigger forward to reset.

Can anyone help me out.