Changing the firing pin spring on a Model 10

I looked through the FAQs and gunsmithing articles but didn’t find any info about this.
I have a 2003 Model 10 in .223. I’m very happy with the precision it is capable of (usually around 0.4 MOA) but it will frequently shoot a “3&2” or have one unexplained outlier. I have heard that weak firing pin springs can be the cause of this. Once I had the firing pin out it looked more complicated than I expected. It seems there are adjustments on both ends of the spring. I figured I better get some advice.

I have never found a weak spring, even in guns over 50 years old. The problem is not the spring, it is the lack of travel.

I agree with Fred. Although I’ve not dealt with nearly as many as he has, I’ve still encountered quite a few with the adjustable style firing pin; and none ever had a spring too weak to effectively light off primers. I recommend setting the pin protrusion to .035” and adjust the Cocking Piece so the Cocking Piece Pin is just off the Bolt Sleeve wall. This will give it maximum Firing Pin Fall, or travel. As to your initial thoughts: I’m not one who believes in “weak” primer firing in Centerfire cartridges. I know it’s an argument in Rim Fire cartridges, but there is no absolute proof that a lighter strike itself can make the primer fire or light off “weaker”. Primers are dumb.. they either light or they don’t; and the overall combustion power of the primer relates to the amount of powder in the primer cup. (Which can vary, and is why Magnum primers offer higher pressure.) For instance, if you lay a stream of gasoline and light one end with a match vs a torch, will the stream lit by match burn the length of the stream slower? Of course not. Again, I know there arguments on both sides. This is simply the side I believe. That aside, with the Savage factory adjustable firing pin spring, if the primers fire, you don’t have to worry if the spring is weak. They are about the most over-sprung firing pin setup I know of. And if the travel is not enough, typically light primer strikes will be the issue.

As to your question though, the video below shows disassembly/assembly and setting firing pin protrusion. The whole video is worth watching, however the firing pin info starts at 14:50 minutes into the video.
https://www.youtube.com/watch?v=foswqsIFBfY

Fliers? You mean like these? :) Just takes a whiff of wind, lapse in concentration, or just a half grain difference in load. Or just luck. :)

https://i.ibb.co/2hVLJfF/small-groups-175-200yd.jpg

https://i.ibb.co/b3X7hRS/small-groups-155eld-500yd.jpg

To be truthful, the 500yd target was pure luck to get the 4 in that small a group.

(Fred says: I have never found a weak spring, even in guns over 50 years old)
BINGO. Look somewhere else.

+1.

Here is an excerpt from a post I made back in 2019. It is basically telling you the same stuff David told you. It is good if info you are trying to find your way back. Some deviate from this info with no issues, howver if you are trying to find your way back home the data helps. problems.

Quote:

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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 also reduced the amount the cocking piece pin rides up the cocking ramp. By doing this you have....) You have only reduced the amount the firing pin will fall when the trigger is pulled. For every full turn(of the cocking piece) 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.

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Complete Article: https://www.savageshooters.com/conte...ng-Pin-Strikes

Thanks to everyone for the excellent feedback. What Dave said makes perfect sense. The “inconsistent ignition” theory doesn’t.

Quote:

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Originally Posted by Gunracr

The “inconsistent ignition” theory doesn’t.

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Unless you are a precision shooter.

Quote:

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Originally Posted by Dave Hoback

adjust the Cocking Piece so the Cocking Piece Pin is just off the Bolt Sleeve wall. This will give it maximum Firing Pin Fall, or travel.

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Is there a photo of what you are describing ? I am trying to picture what is going on here. Thanks!

I don’t have an exact photo, but here is my Bolt. It’s in the “cocked” position here, but once the firing pin falls, the Cocking Piece Pin will be in the region nearer to the red stripe I marked. That edge of the bolt sleeve near the red stripe. You want to adjust the Cocking Piece so the Pin is as close to that without hitting it as possible. It makes sense when the Bolt assembly is all apart. By adjusting the Cocking piece, threading it on the back threaded portion of the firing pin, the hole the Cocking Piece Pin sits in moves closer or further from that porting marked in red. Threading it off moves the hole closer to the blue strip. Although the distance is exaggerated. Mine is set only a couple thousandths off that edge.

https://i.ibb.co/4TK3cFf/EB26-E939-C...381-D00308.jpg

Thank you Dave!