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Thread: Light Firing Pin Strikes

  1. #1
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    Light Firing Pin Strikes

    Firing pin protrusion should be set between .035" -.045" with anything more than .050 being excessive and counterproductive. It has been proven that as little as .020 firing pin travel will ignite the primer once the firing pin makes contact with the primer. This is contingent on a properly sized case with a properly seated primer.

    If your bolt and firing pin have been assembled correctly, there are basically only three reasons for a light strike.

    The first being improperly seated primers. If the primers are not seated properly, they will move inward when the firing pin strikes driving the primer into the pocket. This movement absorbs the energy the firing pin needs to ignite the primer.

    The second being a dirty firing pin/bolt assembly where grime and or gunk will restrict the movement of the firing pin resulting in light primer strike. Poor choice of lubricants can also be the culprit.

    Third incorrectly sized brass. Measure base to shoulder dimensions when setting up your dies. That dimension is critical to the correct and safe function of your rifle. Over sized brass or brass that has had the shoulder bumped back too far can cause issues. You might have a fail to fire or if it does fire, the primer is backed out. A situation where oversized brass has been pushed forward into the chamber and the pressure inside the case forces the primer partially out of the pocket. If this condition is repeated you may see case head separation in the near future if you have not already. If you reload, get tools to check your sizing die adjustment. If you are good you will learn to feel when the shoulder is bumped as you adjust the die down.

    This Hornady Lock and Load tool is very popular for comparing case head space dimensions,



    All things considered you still think there is a problem with your bolt/firing pin....

    When inspecting or rebuilding your bolt and firing pin assembly, measure the compressed spring length and document. Return to as close of a setting as possible when reassembling. Ensure the cocking piece pin is not bottoming out at the lower end of the cocking ramp. There should be a small amount of movement side to side. This will ensure you are getting close to .250" lift of the firing pin. If you move your bolt handle 45* before you feel cocking effort you may have lost half of your firing pin travel from improper adjustment. Turn the cocking piece to down making the compressed spring length shorter and increase the firing pin travel.

    Keep it clean. Use a fine light lubricant if you must. I spray with Kroil and wipe of the access. It is mostly used for a rust inhibitor. Don't use a lubricant that attracts dirt or evaporates becoming sticky and gummy. Make sure the Firing pin assembly slides easily with no friction or drag.

    If you back off the cocking piece thinking that it reduces the bolt lift by changing the spring pressure/preload, you are mistaken. You have only reduced the amount the firing pin will fall when the trigger is pulled. For every full turn you have shortened the Firing pin travel by .036" reducing the energy for igniting the primer. The preload of the spring is not effected by the position of the cocking piece it is effected by the position of the cocking piece sleeve, held in position by the BAS. When the bolt is cocked it further compresses the spring 1/4", the approximate amount the firing pin travels.

    Your chances of light primer strikes due to a problem with your rifle are non existent if you follow these guidelines.



    Trigger/sear hand-off or timing effects firing pin travel and how the bolt closes also. That, bolt lift kits and other Savage firing pin issues are topics for another day.
    Standard rings are like a fat girl sitting on a sandwich.

  2. #2
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    Only "two things" that will cause a light strike?? You better check again.
    Never had issues before so, first thing I check is the OAL of the case.
    Shoulder got pushed back too far or case is just too short for that chamber, firing pin hits the primer, not enough to make it go BANG and case gets pushed forward in the chamber and you get a FTF. The cure?
    By now you've probably got a BUNCH of ammo loaded up. If you pull the bullets out to increase the OAL of the round and the bullet is jammed into the lands, it will be held back against the bolt head and will be fired. May have to single feed if the OAL won't fit in the mag.
    Then, once the round is fired, make sure you DON'T push the shoulder back too far AGAIN when resizing. If it's factory ammo, pull the bullets out "a bit" to increase the OAL (jam) and it should fire. Lots of factory ammo is shorter that needed.
    DON'T BLAME IT ON THE BOLT/FIRING PIN, SPRING or PRIMER TILL YOU CAN PROVE IT!!
    Been there, had that situation and never have had it again. We learn from our mistakes and errors.
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  3. #3
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    Only "two things" that will cause a light strike?? You better check again.
    I'm sorry Mike. I am having a hard time understanding this. Can you help me out.
    Standard rings are like a fat girl sitting on a sandwich.

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    You "did" cover the third thing. I just didn't read far enough to get the detail.

    Most folks jump right to "bad primer" or weak firing pin spring and never consider a brass problem.
    If you say "this is the problem" you better be able to back it up before blaming one thing.
    The firing pin spring is weak.
    The primers are bad.
    Be able to prove what you think is the problem. Don't just throw $$ at it.
    Looks like you pretty much covered it.
    Oz never gave nothing to the Tin Man, that he didn't already have.

  5. #5
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    The firing pin spring is weak.
    The primers are bad.
    Both are pretty rare. The ARC Nucleus has been having problems. I have read about several people including our own Jim Baker that has had trouble with that action.
    Standard rings are like a fat girl sitting on a sandwich.

  6. #6
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    Funny how you can read something and you can't see it. That's what I did with your post, which I might add is VERY GOOD. Sorry for the mix up on my part.
    I see so many times folks being told the primers are bad or the firing pin is weak and both need to be replaced. Just throw $$ at it and that'll fix it. I must have gone thru maybe 5000+ primers with no issues and never had problems with weak firing pin springs on any on my 5+ Savage actions.
    Only FTF was from Brass being resized and the shoulders being pushed back too far. Only primer problem I've ever had was a couple that got oil soaked when the cases didn't get cleaned out after resizing.
    Keep the info coming, you're doing good.
    Oz never gave nothing to the Tin Man, that he didn't already have.

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    Great read and looking forward to your next one.

  8. #8
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    Seems I edited out one of the points I wanted to include so I added it to the beginning
    .
    Standard rings are like a fat girl sitting on a sandwich.

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    All done? If so I'll get it promoted up to the website.
    "Life' is tough. It's even tougher if you're stupid." ~ John Wayne
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urgent circumstances, desperate circumstances, profanity provides a relief denied even to prayer.” —Mark Twain

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    what is the head space gauge called? Does this give the same information that a L.E. Wilson Case Length headspace gauge gives?https://www.midwayusa.com/product/10...eadspace-gauge. I have these in my reloading calibers, and check ever round.

    Can light strikes be had due to loose bolt head screw? I have been getting a few light spikes lately, but when I went to inspect the bolt, I realized the bolt head screw had worked its way loose, maybe a 1/8th to 1/4 of a turn. I tightened it up and was gonna shoot again prior to seeing if it is something else.

  11. #11
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    Jim, if you think it is complete and of assistance to other members... BTW feel free to make any mods you need to.
    Standard rings are like a fat girl sitting on a sandwich.

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    RH, you appear to be missing the star washer between the spring and firing pin stop. Or is that a factory change to the parts count?

    Regarding the rear star washer, I have found that when assembling the firing pin one must take care that the flat on the star washer is positioned as parallel as possible to the flat on the firing pin, and not cocked over as happens frequently when adjusting the cocking piece. This washer tends to catch on the forward most cocking piece thread (the one where the pin profile goes from flat to round and threaded for the cocking piece) during firing pin fall. I grind/polish this to take the sharp corners off. I also grind and polish the flat on the pin body.

    A tendency to catch will increase the firing pin fall time and reduce energy that would otherwise be imparted to the primer.

    I check this for smoothness by assembling the firing pin and installing the cocking pin sleeve properly, place the assembled firing pin upright on the bench (pin upward) and place the bolt head over the pin. Then press down and let it spring back up repeatedly feeling for any tendency to catch. Continue polishing and checking until it operates as smooth as you can make it.
    Long distance shooters are a different breed, and I would never want to piss off someone who can "pick you off" from another zip code.

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    Quote Originally Posted by Texas10 View Post
    RH, you appear to be missing the star washer between the spring and firing pin stop. Or is that a factory change to the parts count?
    Even though this is a Savage Shooters stock photo from another article I can tell it is there because there are not 4 notches showing on the spring side of the pin stop. The one that fits the firing pin stop is smaller in diameter than the one that fits the cocking piece sleeve and it sits flush between the spring and the stop making it difficult to see. The larger cocking piece lock ring is much more visible due to it being larger than the cocking piece and the cocking piece sleeve not being installed.

    Thanks for the comments on the firing pin polishing. I too will put the pin in a drill and polish the area that the spring slides. I grind/file/polish the inside and outside of the firing pin spring as well as the edges of the mouth of the spring on both ends too. I also use a brake hone to clean up the bolt body bore, then flapper stick them with 320 to finish the job. I did not go into all of the things that can be done to a bolt as I wasn't sure that everything I do would be something the guy trying to figure out if the firing pin protrusion was causing his light firing pin strikes.
    Standard rings are like a fat girl sitting on a sandwich.

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    Quote Originally Posted by DesertDug View Post
    what is the head space gauge called? Does this give the same information that a L.E. Wilson Case Length headspace gauge gives?https://www.midwayusa.com/product/10...eadspace-gauge. I have these in my reloading calibers, and check ever round.
    DesertDug, The Hornady gives a reference by way of the caliper. You can measure a fired case and you can set up your die to determine if you have bumped you shoulder back enough by reading the exact measured reference length. I use the term reference because the Hornady tool has parts that add to the measured length making you have to subtract if you need the exact real number for some reason. I believe the Wilson gauges are a go no go type gauge. At least the ones I own are.

    Can light strikes be had due to loose bolt head screw? I have been getting a few light spikes lately, but when I went to inspect the bolt, I realized the bolt head screw had worked its way loose, maybe a 1/8th to 1/4 of a turn. I tightened it up and was gonna shoot again prior to seeing if it is something else.
    If the bolt is not assembled correctly there are no guarantees. If you have tried to fix heavy bolt lift we may need to rebuild your bolt assembly checking off things as we go to get you back where you should be. If you continue to have issues we can work to figure it out by pm or here on this post.
    Standard rings are like a fat girl sitting on a sandwich.

  15. #15
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    Quote Originally Posted by Robinhood View Post
    Firing pin protrusion should be set between .035" -.045" with anything more than .050 being excessive and counterproductive. It has been proven that as little as .020 firing pin travel will ignite the primer once the firing pin makes contact with the primer. This is contingent on a properly sized case with a properly seated primer.

    If your bolt and firing pin have been assembled correctly, there are basically only three reasons for a light strike.

    The first being improperly seated primers. If the primers are not seated properly, they will move inward when the firing pin strikes driving the primer into the pocket. This movement absorbs the energy the firing pin needs to ignite the primer.

    The second being a dirty firing pin/bolt assembly where grime and or gunk will restrict the movement of the firing pin resulting in light primer strike. Poor choice of lubricants or pierced primers can be the culprit.

    Third incorrectly sized brass. Measure base to shoulder dimensions when setting up your dies. That dimension is critical to the correct and safe function of your rifle. Over sized brass or brass that has had the shoulder bumped back too far can cause issues. You might have a fail to fire or if it does fire, the primer is backed out. A situation where oversized brass has been pushed forward into the chamber and the pressure inside the case forces the primer partially out of the pocket. If this condition is repeated you may see case head separation in the near future if you have not already. If you reload, get tools to check your sizing die adjustment. If you are good you will learn to feel when the shoulder is bumped as you adjust the die down.

    This Hornady Lock and Load tool is very popular for comparing case head space dimensions,



    All things considered you still think there is a problem with your bolt/firing pin....

    When inspecting or rebuilding your bolt and firing pin assembly, measure the compressed spring length and document. Return to as close of a setting as possible when reassembling. Ensure the cocking piece pin is not bottoming out at the lower end of the cocking ramp. There should be a small amount of movement side to side. This will ensure you are getting close to .250" lift of the firing pin. If you move your bolt handle 45* before you feel cocking effort you may have lost half of your firing pin travel from improper adjustment. Turn the cocking piece to down making the compressed spring length shorter and increase the firing pin travel.

    Keep it clean. Use a fine light lubricant if you must. I spray with Kroil and wipe of the access. It is mostly used for a rust inhibitor. Don't use a lubricant that attracts dirt or evaporates becoming sticky and gummy. Make sure the Firing pin assembly slides easily with no friction or drag.

    If you back off the cocking piece thinking that it reduces the bolt lift by changing the spring pressure/preload, you are mistaken. You have only reduced the amount the firing pin will fall when the trigger is pulled. For every full turn you have shortened the Firing pin travel by .036" reducing the energy for igniting the primer. The preload of the spring is not effected by the position of the cocking piece it is effected by the position of the cocking piece sleeve, held in position by the BAS. When the bolt is cocked it further compresses the spring 1/4", the approximate amount the firing pin travels.

    Your chances of light primer strikes due to a problem with your rifle are non existent if you follow these guidelines.



    Trigger/sear hand-off or timing effects firing pin travel and how the bolt closes also. That, bolt lift kits and other Savage firing pin issues are topics for another day.
    Interesting “

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