Savage Pin Protrusion Myth - or how to make friends on a gun forum without trying

[Rocketvapor]

It's common knowledge that Savage stock/factory Dry Fire pin protrusion is high @ close to 0.060".
Most say the primer dent stops the pin at around 0.025" deep.
"Optimum" pin protrusion (0.035" - 0.040") is a little over required primer dent (0.025") to allow for some primers below flush, a little headspace, and a little "Extra" just to be sure.

What happens with too little protrusion should be obvious. Misfires, or poor accuracy from weak ignition.
You need "Enough". But is 0.050", 0.060" Too much?
Will a 0.060" protrusion make a bigger dent in the primer? Blank Primers?

Does Pin Protrusion waste pin travel (PIN FALL)?
Two conditions:
LIVE FIRE:
Cocking pin holds the pin and starts at the Sear Hold position.
Pin stops on Primer with about 0.025" dent if it doesn't hang up inside the bolt. That's the reason behind the 0.035" to 0.040" "Enough" pin protrusion recommendation.

Dry Fire- The pin stops on bolt head or bottom of cocking ramp, not on a primer.
Dry Fire is the normal method to measure pin protrusion. 0.035" to 0.040" should be enough to light off any primer.
With dry fire the pin should stop on the back of the Bolt Head before the cocking pin bottoms out in the cocking slot.

You can test by increasing pin protrusion 1/4 turn (0.009") at a time until it stops increasing, indicating the cocking pin is at the bottom of the slot. This is likely greater than the stock 0.060" protrusion.
Maybe all the way up to 0.080" to 0.090" without doing any work on the cocking ramp.
You obviously don't want 0.090" protrusion, but it lets you know where the bottom of the slot is.

Here is my primary point: In Live Fire PIN FALL starts at a point held by the sear, and stops by making a primer dent.
That is PIN FALL.
40, 60, 80 thou Dry Fire pin protrusion will stop when the primer is dented. Won't make it to 0.060".
Start to stop, Live Fire PIN FALL is the same.

Secondary point: So when does pin protrusion matter?
When a "Pro" works on a bolt by changing ramp geometry, changing overall bolt length at the adjusting nut, changing spring force, excessive pin protrusion limits what can be done to customize (increase) PIN FALL.
PIN FALL is one factor along with spring force to have enough impact energy and consistent primer ignition.

So, will I run a Savage bolt with 0.060" Dry Fire Pin Protrusion? Nope, not me.
Just in case I'm wrong

 

[Rocketvapor]

How to measure PIN FALL?
The cocking pin is in a fixed position sitting in the cocking notch.
When moved over to the SEAR HOLD position some DeCocking usually occurs as the sear now holds the cocking pin. When released, DRY FIRE the cocking pin goes toward the bottom of the slot, hopefully stopping on the back or the bolt head and not the bottom of the cocking slot.
With LIVE FIRE a fired cartridge with a dented primer (or a sized case with a spent primer)
can be used to find pin position.

A NEW STYLE BAS, with a hole in it can be used with a depth mic to make these measurements with the bolt installed in the action.
Those are cheap 10mmX5mm thrust bearings from China, not Bolt Lift Kit bearings.
And a 38SPL case mod without ball.



To make 'Relative' PIN FALL measurements you can pin from the front, but this will not account for DeCocking coming off the Notch to SEAR HOLD.

 

[Rocketvapor]

Here's a pic of high/low extreme pin protrusion.


And one method of increasing PIN FALL,

 

[243winxb]

On a Savage Axis , the extractor allows the case to move forward from the pin strike.
The head to datum may become shorter, as a 223 shoulder is pushed back .006" from 1 strike. Up to .013" from a 2nd pin strike, same case.

 

[Rocketvapor]

Thanks for the data.