Firing Pin Protrusion Data.
by
Published on 07-10-2012 11:25 AM
Here are some data points I think are useful and could be incorporated as a sticky. Since there have been a lot of recent discussions about firing pins, I thought I'd consolidate different data in one thread.
Originally Posted by
sharpshooter
First off, you are never going to "puncture" a primer no matter what the protrusion is set at, unless of course the pin tip has a sharp point.
The tip of the firing pin will never indent the primer over about .025". It will bottom out on the anvil of the primer. Typically the protrusion is set from the factory at about .055", which is plenty long and all it does is limit the firing pin travel, giving less impact energy. .035" is optimum.
To measure firing pin protrusion, use the depth measuring rod on the butt end of a set of calipers, put the calipers on the rim of the bolt face, then set your zero on either the bolt face or the firing pin, and then measure to the firing pin or bolt face (whichever you did not use to set zero).
Here's a great picture taken by Blue Avenger:
Originally Posted by
Blue Avenger
Originally Posted by
thomae
The firing pin threads (at least the large diameter one that is in pieces on my workbench) are 28 TPI.
By doing the math, we find that when you adjust the firing pin, each quarter turn of adjustment equates to a change in protrusion (either more or less depending upon which way you turn) of 0.00893". One full revolution equates to a change in firing pin protrusion of 0.035714"
To adjust firing pin protrusion, you need to be able to compress the firing pin spring in order to adjust the firing pin protrusion by turning the firing pin stop nut.
I had an idea for making a Firing Pin Adjustment Tool, but Blue Avenger posted a photo showing a much better/simpler idea: Use a standard set of wire strippers/crimpers as shown in the following photo:
Originally Posted by
Blue Avenger
Originally Posted by
sharpshooter
After you set the FP protrusion, install the spring and the lock washer, then compress the spring and thread the cocking piece on. Adjust the cocking piece until the spring is compressed to a length of 1.900" for a short action, 2.600" for a long action.
DISCLAIMER:
The information contained in this article and the attached video are for educational purposes only. Should you choose to use this information to alter or modify your firearm you do so of your own accord. In doing so you accept full responsibility for any adverse affects, damages, injuries and/or death that may occur as a result. |
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