FP spring weight affecting accuracy

[Michael Huebner]

@jackieschmidt
What can I do to have both easy bolt manipulation and good accuracy ?

An action that has .250+ pin fall will allow a lighter spring, provide very good ignition.
But the trade off is bolt feel when operating the bolt especially if getting the extra fall by moving the trigger back with different hanger

It’s all a compromise

 

[mikecr]

I had a good shooting gun that started throwing flyers. Not an easy problem to solve, but in the end it turned out that the firing pin was slipping in it's cocking piece. Designed setscrew pin holding let me down..
There were no marks on the firing pin, so I did not know where to set it. The only thing I knew was how the gun normally shoots, with my developed load.

So I spent a day at the range taking the bolt apart, adjusting the pin fall, shooting 3-shot groups.
I measured this as pin protrusion from bolt face, and all primers ignited without issue.
What I saw was ugly grouping at ~.200" or less of fall, close up by .245", and then open again past .250".
I do not know the spring force, was purely dealing with the problem at hand(slipped pin).

Amazing to me was the gain in accuracy that I was rewarded with for these efforts (a hidden blessing).
Gun shoots better than I ever would have expected.
But this also means that I never would have reached it without doing this testing (load development alone).

I suspect that this adjustment could help with primer selection. That optimum striking for each different primer could allow for any chosen primer to work well. CCIs -vs- Feds, etc.
This, rather than dictated by primer swapping.
Some day I'll do more testing, and perhaps modify things(like the shroud) for external adjustments.