MarkinEllensburg
posted this
21 October 2023
If running full pressure you have to have a firing pin that is matched to the SRP. Or you will blank primers.
How can this be? What is the difference between a No. 1 in .223 and a No. 1 in .270? A hint for you, the barrel. The block and extractor are the same. The firing pin is contained within the block. Why would any other rifle platform be any different?
I can see why someone would conclude as you @tomme boy based on a test of 4 bolts and three firing pins. Thanks for the challenge, I was able to put to use the gauge pin set I purchased a few months ago. Results of my measurements are:
Milspec m16 bolt that came with one of my ar15 5.56 uppers firing pine hole in bolt .064" firing pin measured .06085"
M1903 I measured two bolts and one firing pin.
Bolt a .083"
Bolt b .082"
Firing pin .080 tapered to .076 right before tip.
Lastly a Ruger Model 77 in .338 Winchester Mag, bolt .079 and pin .078
The 1903 and Ruger both are no question manufactured and designed to be chambered for a LRP sized primer cartridge, that's not to say they couldn't be re-barrelled to a SRP cartridge. I find it interesting that the size difference between the two models is so large. The tolerance difference though is not surprising. The Ruger is not a battle rifle and doesn't require sloppy fitment to ensure functioning in all conditions. The sloppy tolerance of the m16/AR makes sense for the same reasons.
The M16/AR15 was first chambered for a SRP cartridge and has been used for many others since.
Of course I wouldn't be surprised if there are some manufacturers that produce more than one size of firing pin and use such as a marketing tactic. It is amazing the utter BS that gets passed onto consumers to lure them into thinking the something matters when it doesn't.
"But that true-coat.." Jerry Lundegaard