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  #1  
Old 05-11-2020, 10:06 PM
emerson opdyck emerson opdyck is offline
 
Join Date: Nov 2015
Location: NE Ohio
Posts: 113
Default M2 bolt headspace adjusting procedure.

I just wound up with a 1903 with a Numrich .22 conversion and am curious as to the procedure for measuring and setting the headspace using the M2 bolt on the rifle that I acquired, or any of the 03ís that I own.
Thank you
EO
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  #2  
Old 05-22-2020, 01:57 PM
Herschel Herschel is offline
 
Join Date: Oct 2010
Location: Rison, AR
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EO, The M2 bolt with adjustable headspace was meant to permit easy headspace adjustment when the rifle was assembled. There was no intent to have the headspace
changed after the bolt was installed in the rifle. To make sure no one changed the headspace, a set screw or copper plug was inserted into he side of the bolt and into the threads of the headspace adjustment screw to prevent it from turning.

I just looked at the bolt from my Numrich conversion unit. It has the copper plug
jammed into the threads. I have assembled it into a rifle but never fired it.

Apparently the extractor would hold the cartridge case tight enough against the bolt
face to make it safe to fire. After all, the conversion kit does not convert the '03 or '03A3 into a target rifle where the headspace could be critical to accurate firing.
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  #3  
Old 05-25-2020, 05:09 PM
emerson opdyck emerson opdyck is offline
 
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Location: NE Ohio
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Thank you Herschel for finding my orphaned thread...
My M2 is missing both the lead plug and the head space adjustment lock screw, so high would bet that somebody has messed with the head space, probably because like many .22ís, the firing pin has been shortened due to repeated dry firingís.
I am wrestling with how to solve the problem of misfires. The rifle can usually shoot cheep Federals that have a thick rim, but is unable to shoot CCIís which have a thinner rim. (I want to shoot the CCI Quiets) The Fed cartridges are difficult to close the bolt on, and with the CCIís, itís almost impossible, and even then, with the headspace reduced, the rifle will not discharge.
Iíve concluded that I could mill the face of the bolt that meets the face of the chamber insert (not the case head) back .002-.003 and see what happens.
Iíd welcome yours and others opinions.
Thank you.
EO
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  #4  
Old 05-25-2020, 07:18 PM
Herschel Herschel is offline
 
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Location: Rison, AR
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I am sorry I didn't find your thread sooner. I think there is an easy fix to your problem.
First off, I never heard of the firing pin being shortened by dry fring. It is easy to take the bolt apart and look at the firing pin. It should be square cut across the tip. M2's were supposed to be dry fired without damage. The gas defelection nut should be
screwed in finger tight. It is not designed to limit firing pin protrusion by loosening the
nut. I think the thing to do is get some headspace gauges and adjust the headspace
until it will close on the go and not close on the no-go.

The headspace lock screw is a standard thread that you might be able to find to hold the
headspace.

If the firing pin is indeed shortened you can find replacements. I think I even have some in parts box.




a
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  #5  
Old 05-25-2020, 09:02 PM
emerson opdyck emerson opdyck is offline
 
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Location: NE Ohio
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My firing pin face is flat.
What about dry firing against the Numrich chamber insert? Iíll check the insert to see if there is a mark.
If you could measure from the tip of the firing pin, to the face of the firing pin rod, that would confirm that the firing pin hasnít been shortened by smashing into the Numrich chamber face. If itís too short, Iíd never guess that a replacement would be available.
By the wayí what and where is the ďgas deflection nutĒ. Iím looking at the M2 bolt part picture on page 300 of Brophyís book, and I donít see it.
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  #6  
Old 05-25-2020, 09:06 PM
emerson opdyck emerson opdyck is offline
 
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Ahhh!
The firing pin nut is held by a spring? Itís not part of the firing pin rod like an Ď03!
Turn the nut ccw/off and the firing pin protrudes further!
Am I on the right track?
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  #7  
Old 05-26-2020, 07:33 AM
Herschel Herschel is offline
 
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Location: Rison, AR
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The firing pin nut, that I referred as a gas deflection nut, is held by a tiny spring on the
back. It just prevents the nut from backing off when fully tightened. I have fashioned the spring from a common paper clip. If it is missing, you can easily make one but you would need an example to copy. The M2 bolt is no different than the one used on an M2 rifle. Parts for it show up for sale on the big internet gun auction. I don't think you need a part that you can't fabricate yourself. You are on the right track. The firing pin spring pushes the
firing pin all the way forward when not held back by the knurled nut. I have seen comments on the internet, a major source of misinformation, that firing pin protrusion and headspace can be adjusted. That is possible but not meant to be done. I am neither a gunsmith or machinist. Some of my wording might not be technically correct.

Last edited by Herschel; 05-26-2020 at 02:29 PM.
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  #8  
Old 05-26-2020, 07:54 AM
emerson opdyck emerson opdyck is offline
 
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Location: NE Ohio
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Thank you Hershel. Your hint about the firing pin protrusion adjustment is exactly the info I was looking for.
EO
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  #9  
Old 05-26-2020, 02:32 PM
Herschel Herschel is offline
 
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Location: Rison, AR
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EO,

I am guilty of posting misinformation due to a typo.

I meant to say the firing pin protrusion was not meant to be adjusted
by turning the firing pin nut. I have corrected this error in my previous post.

Sorry about that.

Last edited by Herschel; 05-27-2020 at 10:20 AM.
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  #10  
Old 05-26-2020, 08:44 PM
emerson opdyck emerson opdyck is offline
 
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Not a problem.
Thank you for the update/correction.
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