Firing pin stick out for center fire rifles?

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Ru4real

Ru4real

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How far should a firing pin protrude past the bolt face on a center fire bolt face?

Recently I had light strikes and misfires with a new Savage Axis II, a common problem I’ve read. The firing pin protrusion was 0.025” from the factory. So I milled the firing pin rod stop face down 0.020”. Now the protrusion is 0.045” as measured off the bolt face. No more ignition issues.

Yesterday I had a couple fail to ignite with my T/C Venture II. Turns out just bad factory rounds. Today I measured the firing pin protrusion and it is 0.060” as measured off the bolt face. Appears to be plenty.

Today I also measured a Winchester M70, and it’s firing pin protrusion is 0.045” as measured off the bolt face.

Three different guns, three different factory numbers. Is there an accepted thumb rule or number?
 
243winxb said:
https://discover.dtic.mil/ Found here. https://apps.dtic.mil/dtic/tr/fulltext/u2/a114616.pdf

Or search for "Firing pin design requirements"

I would think this is minimum protrusion. The test didnt consider head clearence in firearms.
As said above, Factory specs are different for each rifle.

View attachment 994398
Click to expand...

Hmm. At 0.025” I was getting misfires. Ideal, according to your quote, but maybe head clearance being the key.

I’m thinking 0.050” plus or minus 0.010” is ideal. But I’m not sure, so I asked.
 
I would use .050 as a minimum. I had some problems with my Kimber Ascent last hunting season.
I have another Kimber rifle that I bought used and someone had adjusted the firing pin to protrude too far and it was bent because of that. Straightened it, set it to .055 and has been good for years.
 
They make firing pin protrusion gauges in a variety of flavors. Different manufacturers seem to spec the firing pin protrusion differently using different min and max numbers. I have a Remington 700 bolt laying here and I get about 0.050" which I recall as typical. Most of my rifles average between 0.040" to 0.060". Your initial 0.025" just sounds too short.
Ru4real said:
Recently I had light strikes and misfires with a new Savage Axis II, a common problem I’ve read. The firing pin protrusion was 0.025” from the factory. So I milled the firing pin rod stop face down 0.020”. Now the protrusion is 0.045” as measured off the bolt face. No more ignition issues.
Click to expand...
While as well mentioned the problem can have several causes it appears you got it.

Ron
 
All of my Savages left the factory with something between .045" and .055" of firing pin protrusion. I have been convinced by other smarter people that .035"-.040" is optimum (some folk saying that too much is bad for energy transfer), and I have all of my rifles currently set as close to .035" as can be accomplished within the confines of the Savage firing pin stop's thread pitch / retainer geometry.

I should point out that my rifles have been bolted together closer to the 'min' side of headspace than the 'max'; I suppose that if I had headspace that was close to closing on a no-go-gauge, then maybe I'd find that .035" wasn't quite enough. Dunno.
 
Before measuring anything else be sure to measure the firing pin spring. Savage CF bolt rifles, in particular, are notorious for weak springs. Which is why accuracy specialists routinely replace springs at beginning of tune-ups..
 
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