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Finally, she works


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#1 farinacci556

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Posted 10 July 2019 - 09:40 PM

After months of reading and trying- good info here- I have this 1940 4 digit serial number ex cop Model 50 100 per cent. Most of the info to do this was from here with a few wrinkles. 

 

The gun is about 95 % nicely finished and blued. Hard to believe she's 79 years old. In looking this was the best shape of any I'd seen.

 

Like was posted here, she must be kept clean I clean her after each shooting - 300- 500 rounds. The  20 minutes to do so is is well worth it.

 

Minimal lubrication is all it needs. I have been using a dry lube with just a bit on the ammo as well. 

 

The original 12 round mags work fine BUT. the 22 round ones from Sarco made in Taiwan are ok too. I load them with just twenty for obvious reasons. Sarco has plenty and they are $65.00 each.

 

One thing which was a big help was an extra power recoil spring from Wolff. Got me from 90% to 100 % functioning.I think that because the bolt is so light it needs that extra push.

 

I have 4 30 round mages from Keystone.Only one works. I could not figure out why but I have two ideas. Back in 1940, there were plenty of submachine guns with 30 round magazines, The TSMG later on, the MP 40, Suomi, Lanchester. BUT MOST WERE SLAMFIRE GUNS with much heavier bolts. I'm thinking that' why they never developed a 30 round mag for this gun.   

 

It's easy to see that the M 50 is not as heavily built as the TSMG. But it is several pounds lighter too, and much cheaper, in 1940 and for us.

 

It is not a combat gun for the dirt, mud, etc. But for us who can keep them clean on the range they are fine. Mine is 100 % with 3.9 of Red Dot and a 230 RN plated bullet. That is about half the pressure of the GI load. Good I think for this lightly built gun.The ROF still up there- really can't get less than a three shot burst off. 

 

 

It breaks a firing pin every 500 shots or so but I will shorten one and hopefully fix that, too. Comments welcome

 

 


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#2 StrangeRanger

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Posted 11 July 2019 - 05:11 AM

Sorry, but 500 rounds mean time between failures is not an acceptable number.  Did you put on a full Wolff kit or just the recoil spring?  If you just changed the recoil spring, put in the full kit before you modify the pin.  I am convinced that at least part of the failures that people are seeing are due to weak firing pin springs which allow the pin to move forward when the bolt impacts the top cartridge in the magazine.  A fresh spring should prevent that.  It may also lead to some light strikes so a fresh hammer spring should accompany the fresh FP spring.  The process of installing all the other springs will give you a chance to detail strip and inspect the gun.

 

I don't think bolt weight has much if anything to do with the lack of OEM 30 round mags.  The recoil spring on a Reising is much stiffer that that of any of the slam-fire guns and gives more than enough force to do the job.  My 30 round Christie mags run flawlessly as do 2 of my 3 Keystones.  I think Keystone simply has some quality control issues.


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#3 farinacci556

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Posted 11 July 2019 - 01:58 PM

Yes, I put in the new firing pin spring. I see that the primers strikes are much heavier than anything else I've seen other than mabe a 1st gen SAA. Never had a misfire I think that pin needs to be just a bit shorter to avoid breakage.

 

 

Maybe I'll try a Christie mag or two. I kinda like the way she feels with the 12's or 20's. If you got a bolt for sale please advise- best MC

 

PS I am buying a Thompson- can't help it


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#4 farinacci556

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Posted 12 July 2019 - 06:11 AM

How long to you thing a firing pin should last?


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#5 jim c 351

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Posted 12 July 2019 - 06:22 AM

Approximately 100 years.

Jim C


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#6 johnsonlmg41

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Posted 12 July 2019 - 08:55 PM

I have several pushing 80 yrs.  I don't see why most of them won't go 100+?

I've never personally broke one?  Like a lot of Reising problems that seem common, one needs to keep in mind it's a starter gun for a lot of folks and there a LOT of them in the registry.  You don't hear much about MG81's that shred parts frequently, because there aren't a lot of them, and because few shoot them....afraid to break things that may not be replaceable.


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#7 cmadzela

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Posted 14 July 2019 - 08:00 PM

Got my M50 at KCR from OOW in 2003ish; I had put about 6,000 rounds through it before the pin broke The pin from "birth" was a clean break (see attached photo). I was firing at the range and it just stopped; shaking the gun made a distinctive clacking sound; came home and discovered a freshly shortened pin. Replaced with titanium pin from GunBroker auction. That was 2012 when it broke; just put 200 rounds through it today. Maybe now at another 4,000 for a total of 10,000 rounds total in my life. The pin and the action bar have failed. Otherwise.... I love mine. She's old but she can certainly rock and roll.

Attached Files


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#8 deerslayer

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Posted 15 July 2019 - 07:44 PM

I put a titanium firing pin in a post sample build that was being difficult... Bending the firing pin after a couple mags.. That solved the problem.
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#9 StrangeRanger

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Posted 16 July 2019 - 10:54 AM

Deerslayer

It has been my contention that the firing pin protrusion/cartridge jam occurs when the bolt hits the back of the top cartridge in the magazine but the firing pin has enough momentum to keep moving forward when the bolt slows on impact and the pin's tip is hit by the rising cartridge.  In many cases this impact is self clearing and not evident at the time that it occurs with only the worst cases creating the actual jam but the damage accumulates over time.  I think that this is what causes a significant portion of the bent pins.  The titanium pin weighs roughly 2/3 of what the steel pin does and therefore has substantially less momentum and is proportionally less likely to suffer this sort of jam.

 

Does this seem like a reasonable analysis to to you?  If so would not a stiffer firing pin spring alleviate the problem?


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#10 jim c 351

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Posted 16 July 2019 - 10:54 AM

farin,

Glad to learn you got your Reising working.

Sadly ,by making your post you just jinxed yourself.

Jim C


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#11 skoda

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Posted 17 July 2019 - 08:56 PM

Deerslayer

It has been my contention that the firing pin protrusion/cartridge jam occurs when the bolt hits the back of the top cartridge in the magazine but the firing pin has enough momentum to keep moving forward when the bolt slows on impact and the pin's tip is hit by the rising cartridge.  In many cases this impact is self clearing and not evident at the time that it occurs with only the worst cases creating the actual jam but the damage accumulates over time.  I think that this is what causes a significant portion of the bent pins.  The titanium pin weighs roughly 2/3 of what the steel pin does and therefore has substantially less momentum and is proportionally less likely to suffer this sort of jam.

 

Does this seem like a reasonable analysis to to you?  If so would not a stiffer firing pin spring alleviate the problem?

StrangerRanger,

 

I think you figured it out. I had the same problem even with the Keystone titanium firing pin though reduced from the steel pin. I filed it down like you suggested in another post and it runs a lot better. I also landed up using some teflon spray on the mags and ammo to get the feed rate of the magazine up to meet the rate of bolt cycling. I'm normally using rough finish steel case ammo. Brass runs better.


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#12 deerslayer

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Posted Yesterday, 07:13 AM

The steel firing pins ones were bent like above picture.. But the failures were ultimately a weak primer hit on a completely closed bolt, not a protrusion jam. I didn't think to use the super show motion video on my phone to capture the action cycling... I've used that before too identify problems in other mgs. That could have identified what has been proposed here to perhaps. And now I don't have the gun anymore.
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#13 StrangeRanger

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Posted Yesterday, 11:23 AM

Here's another thought.  The bending strength of a round column, in this case the firing pin, is proportional to the diameter to the fourth power.  The current stepped design of the Keystone pins is .175" just before it steps down to .085" to pass through the hole in the bolt face.  The diameter of the stock tapered pin at the same point is only .093".  The tapered design gives an increase in bending strength of (.175/.093)^4 or 12.5.  The differences in the yield strength, (i.e. the load which causes it to bend) of the two metals is hard to determine because the steel originally used is unknown.  The yield strength of titanium is comparable to the better grades of alloy steel and much better than most of the more common grades.

 

So it would appear that the Keystone pins are at least 12.5 times as resistant to bending as the original steel ones. 


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