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How much firing pin protrusion is needed for good reliable rimfire ignition?


Here is my thinking so feel free to correct and help me out where needed:


Headspace is approx .043, and maybe a little extra .00+.


The Firing Pin protrusion (assuming adequate force is applied to strike the rim) should probably be

approx .025 minimal..........   .035 max.


Any advice, info, etc.... you may have to help give me better numbers will be appreciated.






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Those numbers are about 'rite'.

I don't like anything less the .025 FP protrusion on .22 RF.

Make sure the FP has a good flat point with good clean edges.

Just as long as the FP gets a good smack....All should be good.

What's ya build'n now? :huh:


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Thanks Lumpy.


Nothing new.   But, some of the Henry .22's I've seen lately appear to have shorter than normal

length on the firing pins.   It ain't common, but it does happen.


I thought I had my figures pretty much on the mark but it never hurts to hear from others

about these things.   No man is an island.




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3 hours ago, Chili Ron said:


I would call the Henry folks and see what they think.

I bet you get a reliable reply.





Thanks Chili.   Thats a good suggestion.


To share more info, here's is what I have found.

Based on some Henry .22's, when the firing pin is struck by the hammer, the protrusion is about .017 - .020.

Using the factory SUPER strong hammer spring, this protrusion length is adequate for reliable ignition on

most ammo.   Admittedly, there appears to be some .22 ammo on the market that has sensitive ignition

over other ammo.


Anyhow, when the hammer spring is 'tweaked'  (cutting approx 1.5 coils off the hammer spring),

that .017 protrusion doesn't seem sufficient for 'some' ammo.

CCI seems to give constant ignition but some other fodder doesn't give ignition reliability.


Soooooo, I'm working the rifle bolts to give somewhere between .025 and .030 firing pin protrusion.

This is giving excellent hit marks on the rimfire ammo and 100% ignition.


And before anyone ask..... YES, I am checking bolt face rim depth, firing pin length and firing pin bolt slot 

measurements before making any mods.    


Hopefully, some of this info might help someone who has a problem with ignition of their Henry .22

when using certain brands of ammo.




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