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Discussion Starter · #1 ·
I am the new owner of an old 1907 Model 97 and I am trying to clean up the firing pin. I need advice. (Please excuse me if I get some of the terminology wrong, I'm a novice!)
The original/old firing pin in the rifle seems to strike the bullets well, but there is some damage to the end of the barrel, probably from dry fires when the magazine tube reaches empty. Closer inspection leads me to believe the firing pin has been cut so that it can extend too far forward and hit the end of the barrel.

Here is a picture of my old pin and the new Wisner firing pin I bought.
The new pin is the darker one on the bottom. It is approximately 0.016” shorter than the old pin. The old pin is 2.767” long and the new one is 2.751”.


You can see the old pin on top has the striking edge cut to be shorter (A). You can also see the pin stop (B) is cut back to allow the pin to go further forward when the hammer strikes it.


From above you can see the old pin (on the bottom in this photo) is narrower on the striking edge.


Here is the concerning part. This is the old pin in the bolt. You can see it protrudes a long way forward. In fact it reaches as far forward as the extractor hook. The stop on the pin isn’t restricting it’s forward motion enough (in my opinion).


Here is the heel of the bolt, you can see the pin slides far into the bolt. Too far? Shouldn’t this be flush?


Here is the front of the new pin in the bolt. Does this stick out far enough?


And here is the heel of the new pin in the bolt. It protrudes just a bit and isn’t quite flush with the bolt.


And here is a crucial shot of the strikes on some dummy ammo. On the left is the old pin. Looks good to me. On the right is the new pin; not much of a mark and it is hitting hardest closer to the center.


So…
I’m a novice, but here is what I think.

Old Pin: Nice strikes on the ammo, but goes too far forward and is injuring the end of the barrel on the occasional dry fire.

New pin: Lousy strikes on the ammo, doesn’t go forward quite enough. Could it damage the hammer by sticking out of the heel of the bolt? Surprisingly shorter than the old pin.

Plan: What do the experts think? I think I should take the new pin and file the tip to resemble the old pin. And I think I should file the stop a bit so the new pin can go forward enough to be flush with the heel of the bolt. Should the pin go below flush of the heel?

Ideas and comments?
Carl
 

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I have to say I am a little confused - first, have you shot the rifle? if so, are you using ONLY standard or low velocity ammunition? (that is a must or you will break your bolt!). Why did you order a new firing pin? Was there a problem before? You should never dry fire a .22 rimfire - all pins will damage the edge of the chamber, and most times it will lead to their breakage after repeated action. Have you tried the Wisner pin? Do not alter it prior to trying, or proving its' function on live ammo, is my opinion. If the old pin works, why change? the hammer cannot be damaged in my opinion. good luck and shoot straight, gewehr
PS you did a great job with the pictures and measurements
 

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Discussion Starter · #3 ·
If the old pin works, why change?
As I mentioned, there is damage to the chamber from the pin strikes, the gun came to me like that. I know to avoid dry firing, but I also know that sometimes when I get to the end of the magazine I'm likely to do it occasionally. Examining the old pin I noticed the items above, particularly how far the old pin can reach forward and strike the end of the barrel / chamber. I've got more than a dimple of damage! So I think this need to be addressed before using the gun. And it's a fun project!

What are the pins like in other '97 and 39? Do they go as far forward as my old one does? Does the stop hold them back properly? Have they been "sharpened" like mine?

(I haven't fired the rifle yet. I will only use subsonic ammo lead round nose, I just purchased a brick of the nearly impossible to find stuff.)

Carl
 

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My 39 firing pin sticks past the bolt face further than any of my newer 39a's. I think I would use as is to see if there is a problem. As a side note chamber pressure is the problem with the High velocity ammo some of the sub sonic has the same pressure as high velocity (I believe) just uses heavier bullets to slow em down. I would hate for you to crack a bolt.
 

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I'd file/grind the new pin to where it is flush (or a bit into) with the back of the bolt and give it a try.

Luisyamaha
 

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Marlin 97, it looks to me that the face of the old firing pin that stops its forward movement may have been altered. There appears to be a lot of machine marks all over the sides also. I have never inspected a really old firing pin though.. The new firing pin needs to have the tip shaped and the forward leg for lack of better term needs to be rounded to allow the firing pin (new) to fully contat the rim of the shell but not the breech face, top picture. The three firing pins are from a '59 vintage , a '73 vintage and Numrich or Midway replacement part. I fitted a new firing pin to my '59, it took a few hours of carefully filing and stoning to get the firing pin to work correctly. You will notice that there are different shapes for the face of the firing pin (where it strikes the rim of the shell). I have no preferrence, pick one and try to execute its shape on your firing pin. SHARP files are required to get the step in the face, again just take your time.







Here is an old thread with a little of the same info, and some fitting tips:
http://www.marlinowners.com/forum/rimfires/88118-1947-marlin-39a-firing-pin-broken.html
On a final note, sorry if it has already been mentioned, I wuld have a smith clean up the chamber and barrel face, shouldn't cost much and would likely help with feeding/ extraction.

Luisyamaha's suggestion to shorten the tip of your old firing pin will get you back into the game faster, and is certainly a solution to you issue

Good Luck, Let us know how it goes!

James
 

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Discussion Starter · #11 · (Edited)
After a bunch of looking, I found a great book: "Gunsmithing" by Roy S. Dunlop. It gives some good basic information on setting up your firing pin:




The diagram claims the pin should protrude 0.035" to 0.039" from the face of the bolt. And it gives some nice pictures of the end of the pin.

This post in another thread was also very useful:
ouch.2 said: "I just got and watched the AGI video for the Marlin 39 and 39A. It was probably made in the mid 1980's. It is pretty good with a decent amount of info on the workings and common problems with the 39's. It has for me most importantly a section on fitting the firing pin with .022" minimum to .044" maximum protrusion on the shell seat and .001" to .002" below the bolt surface on the hammer side when the pin is fully forward for both of those measurements. If your pin doesn't move that far forward than you need to file down the stop to allow it."
http://www.marlinowners.com/forum/rimfires/88118-1947-marlin-39a-firing-pin-broken.html#post1019246

Using that and info from pocket pin and other posts I modified my existing new Wisner pin. I notched the end and filed the sides to make a smaller striking surface. I was careful to bevel the edges so they aren't too sharp. And then I filed down the "stop" so the pin protrudes approximately the correct amount. I was careful that to make sure it wouldn't go too far forward.


Here is a shot of the new tip:


Here is the heel of the bolt, without any ammo in the chamber. I've filed down the "stop" enough so the end of the pin is just barely below flush with the heel of the bolt (while still making sure the tip didn't extend too far forward).


The mark on dummy ammo looks OK. But I'll have to test it with live ammo to be sure.

Carl
 

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Discussion Starter · #12 · (Edited)
Good news and bad news.
Good news first.
Here's a pic of the end of the new pin. Sorry about the lint and blur. ;-) It might be protruding a bit far. I have a caliper, but it doesn't work well in this location. I judge that it might be a bit high by the height of the standoff next to it: its just a bit shorter than that standoff. I think that standoff defines the headroom.


And here is a pic of the strike on a dummy round.


Now the bad news. I'd been planning on taking the rifle out for some test firing tomorrow. But on very close inspection, I think I see a small crack in the bolt. I've read that this is where it cracks if high velocity ammo is used. Sigh. See the small red arrow in this picture.


Now I'm wondering if I can find a true gunsmith who could weld this up. While he is in there maybe he could weld up the hammer marks on the chamber...
Anyone have a skilled smith that they recommend in the San Diego area?
 

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Check the rear of the bolt for squareness

Two things.
First: It's true that the firing pin should protrude by the amounts mentioned, and this is usually accomplished by filing the shoulder on the firing pin stop, as also mentioned. When it's all done, though, the firing pin should sit just a thousandth or two below the REAR face of the bolt when it is in its forward-most position (without a cartridge in the chamber). If not, the firing pin--or the bolt itself--could be damaged as the hammer slams the firing pin stop into the the end its slot in the bolt. Ideally, the hammer should hit the rear face of the bolt right before the stop on the firing pin comes into play. In other words, when the firing pin is forward, up against its stop, and the hammer is at rest, down against the bolt, there should be a gap between the firing pin and the face of the hammer of 1 or 2 thousandths.

Second: I ran into another situation that I've never read about anywhere. On one of my 39's, the firing pin protrusion was fine, but I still had light strikes. I finally discovered that the hammer wasn't pushing the firing pin as far forward as it should because the rear bolt face was out of square, with the right side being higher than the left. Consequently, the hammer wasn't hitting the rear of the bolt face squarely, but rather only the area to the right of the firing pin. The hammer wasn't making contact with the left side of the bolt face at all. I first discovered this when I noticed the witness mark on the hammer. That mark showed that it was hitting the rear face of the bolt on the right side only. That meant that either the trigger was crooked or the bolt face was out of square. One of my photos shows the bolt with my square up against it. I took this photo after I fixed it. I wish I would have taken one before to show the difference, but trust me, it was not square. It was out of whack about 4 or 5 thousandths, I'd guess. I fixed it by carefully filing down the high side, checking with my square after each pass or two with a fine file. Next thing I knew, it was flat and square. I did not remove any material from the low side, but rather only enough on the high side to make it square. New witness marks on the hammer afterward confirmed that it was now hitting square and flat. I haven't had a misfire since.




Below is the finished product, the pencil pointing to the area that I filed flat.

 

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