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  #1  
Old 05-15-2016, 11:49 AM
redmist
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Mod. 38 Pump



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Help ! I've been looking for a schematic / disassembly tutorial for a Mod. 38, and am unable to find it in any of the usual places. The "Parts List" available on some sites is just about useless for parts i.d. or disassembly. I can take it down for cleaning, but after reading Pump 22's great post, I think I may have to replace the firing pin and am hesitant to try without guidance.
Anyone offer any help ? Thanks.
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Old 05-15-2016, 08:27 PM
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I have owned a number of the Model 38 rifles, and one thing I noticed....a significant fraction of them had firing pin issues. From what I was able to see, the firing pin rides in the bolt in such a way that the strike is quiet close to the edge of the case rim. Time, use and resulting wear seems to enlarge the hole or channel in the bolt in which the firing pin rides....this extra wear creates "slop" or loose fit and allows the firing pin to ride even further out....producing strikes that don't catch enough of the area of the case rim where the primer is concentrated.....resulting in frequent or complete FTF. I know of no simple fix....a new pin might help but can't totally compensate for the wear in the firign pin channel. For some reason, Marlin chose to cut the channel so that the firing pin was striking close to the case edge...even in new guns from what I can tell. Wear eventually leads to problems....a new pin may help but can't compensate for the wear in the bolt firing pin channel. Heavily worn bolts show oversized firing pin holes in the bolt face.

One thing I have done in cases where I felt I had nothing to lose...but I can't recommend this....unless you have nothing to lose, is listed below. Again, I am not recommending this except in worst case scenarios...

1) I carefully ground some surface of the rear of the bolt where the hammer strikes......to get a little more strike on the back of the firing pin, not much....just a little.

2) I removed some material from the firing pin itself in the appropriate area to allow it to move further forward....to get a little more firing pin tip sticking out the front of the bolt. I can't recall exactly what I did....it's been a few years.

3) The firing pin tip is normally round. I carefully peened the end of the firing pin tip to a more flattened shape...flattened in the direction that would allow more firing pin strike on the cartridge case. This got more strike onto the case itself, since I basically widened the tip of the firing pin in the critical direction....making it wedge shaped instead of round. I may have honed some of the outside edge of the firing pin tip to avoid contact with the chamber rim. Caution: the firing pin is hardened.......I went very slowly carefully peening the very tip while held at the correct angle against an anvil and striking the tip at the correct angle. A hit anywhere except on the very tip can result in a broken firing pin. I have pretty good feel for what I can get away with where metal is concerned.......do this at your own risk. Being done by someone with out a good "feel" for what they are doing has a high probability of resulting in a broken pin. Wisner's may have new firing pins...can't recall. Parts for these old guns can be difficult to find.

But the upshot was that I got some guns to shoot well that otherwise were non-firing. Another thing...I did get a new firing pin for one gun....but the firing pin channel was so worn that I still had to resort to the tricks above.

The Model 38 was/is prone to some other weak spots. The pivot pin where the gun pivots for breaking down will wear and result in slack. There is an adjustment screw at the rear top of the back receiver designed to take the slack out, but these frequently freeze up. The sliding safety is prone to wear and in worn guns, will not stay in place.

I sold my last model 38 a few months back - I'm in the process of downsizing my collection. But I do have a few parts.....all except for the bolt and it's associated parts.

Now, after saying all this, I'm not sure what your problem is, except to say that you indicate it may be firing pin related. You don't say if the gun will not fire, or fires only infrequently, or if there is some other issue or issues. But I took a shot in the dark here...hope it helps.

For what it's worth and it may not be worth much.

Last edited by pump .22s; 05-15-2016 at 08:47 PM.
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Old 05-16-2016, 11:07 AM
redmist
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Mod. 38

Thanks so much for your reply. While reading the Pump section on this forum, I found your original Mod. 38 post which is what prompted my post here. I also sent you an email hoping for some guidance. I have intermitent failure to fire. Rarely happens when shooting offhand, but almost always from the bench using a rest under the forearm (???) I managed to find a firing pin from Numrich, and though I don't know if it would be a fix, I'm willing to try it. Problem is, the complex bolt assembly intimidates me. I don't want to try it without a good schematic / disassembly instructions. I've looked everywhere but can only find a pretty useless parts diagram. If anyone has a good schematic or instructions to share, I'd be most grateful.
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Old 05-16-2016, 11:56 AM
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Quote:
Originally Posted by redmist View Post
Thanks so much for your reply. While reading the Pump section on this forum, I found your original Mod. 38 post which is what prompted my post here. I also sent you an email hoping for some guidance. I have intermitent failure to fire. Rarely happens when shooting offhand, but almost always from the bench using a rest under the forearm (???) I managed to find a firing pin from Numrich, and though I don't know if it would be a fix, I'm willing to try it. Problem is, the complex bolt assembly intimidates me. I don't want to try it without a good schematic / disassembly instructions. I've looked everywhere but can only find a pretty useless parts diagram. If anyone has a good schematic or instructions to share, I'd be most grateful.
I don't think I got the email....

When you get the firing pin from Numrichs, get it installed and working....then you will be comfortable in trying some of the mods I suggested on the firing pin. That way, it you break it for ruin it, you have a new one to fall back on.

I no longer have a 38 bolt to look at, and my memory is short and fuzzy on that. But if you carefully examine it, you will see how to remove the firing pin. It may require driving a pin out or some such....I just can't recall.

Good luck.
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Old 05-16-2016, 09:27 PM
WalnutBill22
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Hi Redmist and welcome to the forum. I just checked my Model 38, and it doesn't appear too hard to change out the firing pin. First, of course, take it down and remove the bolt. You may have to push in on the rear of the firing pin to unlock the bolt. Slide it all the way to the rear and tilt the bolt upward from the rear to remove it from the slot in the action bar. There is a small transverse pin at the rear of the bolt that you will have to tap out using a small punch. Tap it from left to right to remove it and the firing pin should come right out. You may have to tap it out from the front. Be careful not to lose the little pin. Reassemble in reverse order. If your new firing pin doesn't cure it, you may need to do as Pump 22s advised and remove just a slight amount of metal at the rear of the bolt where the hammer hits the firing pin. Don't remove any metal from the firing pin itself, just the bolt. Good luck with it.
WB
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Old 05-16-2016, 10:13 PM
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Originally Posted by WalnutBill22 View Post
Hi Redmist and welcome to the forum. I just checked my Model 38, and it doesn't appear too hard to change out the firing pin. First, of course, take it down and remove the bolt. You may have to push in on the rear of the firing pin to unlock the bolt. Slide it all the way to the rear and tilt the bolt upward from the rear to remove it from the slot in the action bar. There is a small transverse pin at the rear of the bolt that you will have to tap out using a small punch. Tap it from left to right to remove it and the firing pin should come right out. You may have to tap it out from the front. Be careful not to lose the little pin. Reassemble in reverse order. If your new firing pin doesn't cure it, you may need to do as Pump 22s advised and remove just a slight amount of metal at the rear of the bolt where the hammer hits the firing pin. Don't remove any metal from the firing pin itself, just the bolt. Good luck with it.
WB
Your post jogged my memory. Sometimes the bolt is pretty easy to get out of the receiver. Sometimes, depending on the gun, it feels like a Chinese puzzle getting the thing out. But it will come out.
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Old 05-16-2016, 11:20 PM
redmist
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Mod. 38

Thanks Bill (and Pump 22). I have the firing pin from Numrich. I think my first step will be to replace the pin with no modifications and see if it cures the problem. If the problem persists, I'll screw up my courage and try some of the mods you both suggested. I realize the Mod. 38 was not a high number production, but I'm amazed that there doesn't seem to be a schematic of it anywhere, at least nowhere that I've been able to find - baffling.
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Old 05-17-2016, 07:58 AM
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Quote:
Originally Posted by redmist View Post
Thanks Bill (and Pump 22). I have the firing pin from Numrich. I think my first step will be to replace the pin with no modifications and see if it cures the problem. If the problem persists, I'll screw up my courage and try some of the mods you both suggested. I realize the Mod. 38 was not a high number production, but I'm amazed that there doesn't seem to be a schematic of it anywhere, at least nowhere that I've been able to find - baffling.
PM me an email address and I'll send you some stuff I have....including patent drawings for the Model 38.
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Old 05-17-2016, 11:27 AM
redmist
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Mod. 38

Wow ! That would be great, thank you. Will p.m. you, but just in case:
[email protected]
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Old 05-26-2016, 06:38 PM
redmist
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SUCCESS ! As promised, a follow up on my Mod. 38 misfires:
I removed the firing pin (thanks Bill) and took out the digital calipers to compare dimensions of it and the Numrich replacement. a) The OAL of the replacement is .0225 SHORTER than the original. b) The diameter of the replacement is .0015 LARGER in diameter - not much, but apparently enough to make a difference. Also, the tip on the original was flat whereas the replacement had a tip that was more rounded, or bullet shaped. All other dimensions were the same. As for the tip shape, the original may have been modified sometime the past in an attempt to improve misfires. 100 years is a long time for many hands to tinker with it. The firing pin tunnel in the breech block was unquestionably sloppy. The diameter was probably as much as 10% larger than the firing pin diameter (I was unable to measure the inside diameter), and most certainly, this slop combined with gravity, contributed to the misfires. This "slop" has been attributed to wear, but I have my doubts. Even if the firing pin was much "harder" than the breech block steel, I can't see how the pin, traveling in a linear direction through the hole in the breech block, could wear and enlarge the hole. My conjecture is that it was more likely a case of incompatible dimensioning of the two parts. Be all that as it may, at the moment it is functioning reliably (fingers firmly crossed), and I very much thank you all for your help, guidance, and information provided.
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Old 05-27-2016, 12:12 PM
WalnutBill22
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Great! Always glad to hear when something works out well for a poster. The old Model 38 is a very neat rifle, just a little more complex and cantankerous than some others. As others may have told you, it would probably be best to stick with standard velocity ammo.
Good job.
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