Firing pin fall

Canadian Bushman

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What is firing pin fall, how can it be tuned, and what effect does it have on the ignition process?

I hear the term used when talking about timing an action but ive yet to hear a clear description of "firing pin fall."
 

FearNoWind

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Firing pin fall is the forward movement of the firing pin from it's point of rest to its contact point with the primer. It's an element used in calculating firing pin impact and other mechanical factors involved the movement of the firing pin when firing the rifle.
 

Punisher

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You will also read about lock time. The time it takes for the pin to be released and make a strike on the primer.

I am unsure by your terminology if you are referring to the pin strike in relation to the center of your primer, or the lock time.
 

jsthntn247

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It's a very complicated thing to understand that only a handful of gunsmiths know how to maximize it. It all has to do with trigger timing, cocking mechanisms and handoff's. The guru's seem to be Jim Borden and Greg Tannel. A borden action is supposed to be more perfect from the get go as far as lock time and action timing than any other.
 

Canadian Bushman

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It's a very complicated thing to understand that only a handful of gunsmiths know how to maximize it. It all has to do with trigger timing, cocking mechanisms and handoff's. The guru's seem to be Jim Borden and Greg Tannel. A borden action is supposed to be more perfect from the get go as far as lock time and action timing than any other.

Thats sorta the impression ive been getting. When detailed questions start getting asked things get quiet. The guys who do know dont want to say much. I was hoping a ball would get rolling and id get an opportunity to understand more about how all the aspects of timing an action come together but it doesnt look like that is happening.

Ive also read the same thing about borden actions. Also bats tend to struggle in this area and require some tuning.
 

BountyHunter

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You are talking PIV (pre ignition vibration)

Dave Tooley is another master at this and his Orion action has some major tweaks in this area also.
 

Canadian Bushman

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You are talking PIV (pre ignition vibration)

Dave Tooley is another master at this and his Orion action has some major tweaks in this area also.

Yes im curious about this as well as the mechanical operation of the bolt as it locks into battery.

Does the strike always increase PIV when firing pin fall is increased?
How do you know if you need more or less fall to tune a load?
Is it basically a goal to have as little fall and striking force required to reliably set off a round?
 

Canadian Bushman

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My main focus of inquisition when starting this thread was the sequence of events that happens when a bolt is locked into battery. Basically the actions jsthntn247 listed.

Like how the chamfers on the lugs pull the bolt forward handing the pin to the sear on the trigger. How critical is this action? Are the angles and symmetry crucial to the smoothness of the action? Does this effect the consistency of firing pin fall?

Or is a precise fall and ignition force more oriented around the cocking piece and cam?

Do you tune this action by the chamfers on the lugs or by grinding the location of the cocking piece?

When a bolt is trued and lapped, how is the timing reset?

I really need to learn all the proper names of the pieces of a bolt so i can ask questions of more clearity.
 
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bigngreen

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A friend of mine times actions and it's amazing how smooth an action can operate when each step is at the correct time with no over working, he's a BR shooter and I can really see the importance of timing there where you need that rifle to function smooth without disrupting it in the bags. In a hunting rifle I really noticed just how nice a timed action is to run after firing, you don't have the lift of cocking then the dead space between cocking and primary extraction, it's just one smooth as butter movement. Same with closing the bolt, you don't have the bolt handle snap down a little from the cocking piece dropping to the sear then having to shove it down while the lugs are pulling the bolt forward recocking it, you just get one smoother straight down bolt close.
 

Canadian Bushman

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A friend of mine times actions and it's amazing how smooth an action can operate when each step is at the correct time with no over working, he's a BR shooter and I can really see the importance of timing there where you need that rifle to function smooth without disrupting it in the bags. In a hunting rifle I really noticed just how nice a timed action is to run after firing, you don't have the lift of cocking then the dead space between cocking and primary extraction, it's just one smooth as butter movement. Same with closing the bolt, you don't have the bolt handle snap down a little from the cocking piece dropping to the sear then having to shove it down while the lugs are pulling the bolt forward recocking it, you just get one smoother straight down bolt close.

So you can understand my desire to learn more about how this all comes together? Next time you talk to your friend, could you probe his mind a little?
 

arrow

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So I understand this thread is almost 4 years old, but is there anyone who can explain how a 700 action is timed? I have read all over the internet and nobody explains it. This thread seams full of people looking to learn. Anybody figured it out in the last 4 years? Thanks
 
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