8 pounds verses 23...

8 pounds verses 23...


CYA friends:


I've spent this day pondering 8 pounds verses 23.


My triple lug spearment that I sent to the barn a year ago, that Robert Oates kicked out that amazing PSL card with, and this new DiOrio triple have identical ignition.


My triple spearment is as free as this new DiOrio V-3.

The only difference is, I worked hard to make my spearment free.

This V-3 was free right out of the box.

Will they all be this way?



Both are driving a .033" width pin to exactly the proper depth, with the footprints at exactly the same location inside the rim of the case head, without over driving them.


I know of no way, today, to produce more consistent rimfire ignition than these two actions are now producing.



Yet, one pin is being driven with 8 pounds of firing pin spring pre-load @ 1.750" compressed length.


And the other is being driven by 23 pounds of firing pin spring pre-load @ 1.750" compressed length. ( an early Wilkinson spring )



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So I've spent this day trying to figure out why.


I'm not finished.


Your friend, Bill Calfee

Total Firing Pin Travel?

Hi Bill,

With everything else being equal, except the spring pressure......what's the difference in the "Total Firing Pin Travel" between the two?

Question: If you make adjustments to each rifle so that you can achieve equal firing pin travel and equal spring pressure.....do they then have the same foot print (case head penetration). I'm thinking to lower the total firing pin travel on the new 3L to the highest that you can achieve with the experimental test rifle.....then use equal springs in each and see what the results are?

Hope this makes sense.....you've most likely already tried this.

Jeff

Friend JP65

JP65 said:

Hi Bill,

With everything else being equal, except the spring pressure......what's the difference in the "Total Firing Pin Travel" between the two?

Question: If you make adjustments to each rifle so that you can achieve equal firing pin travel and equal spring pressure.....do they then have the same foot print (case head penetration). I'm thinking to lower the total firing pin travel on the new 3L to the highest that you can achieve with the experimental test rifle.....then use equal springs in each and see what the results are?

Hope this makes sense.....you've most likely already tried this.

Jeff

Click to expand...

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Friend JP65:


I have not done that specifically, yet.....but I will and thank you.

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Here's where I'm at:


This new V-3 firing pin is slightly heavier than the 10-X pin......I'll try to determine exactly how much heavier shortly.


The 10-X, from the firing pin spring retaining pin to the end of the counter bore for the firing pin spring, when at battery, is longer than the V-3.


The difference is about .140"...


And the firing pin travel between the two are also different.

The 10-X is .190"

This V-3 is .216"


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Jeff, these differences account for some of what's happening here, with both actions creating equally consistent ignition, yet one with 8 pounds and the other with 23 pounds of spring pre-load.



If I back the V-3 down to .190" of firing pin travel, and if I remove enough of the Wilkinson 23 pound spring to account for .140" of compression length, will the two pins wind up being driven by the same firing pin spring pre-load?


We also need to keep in mind, the V-3 will have a slightly greater momentum factor since the firing pin is slightly heaver.


But if we think about it, the pin being heavier actually complicates the question of how 8 pounds is driving it like it is.


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There's two bottom lines here.


One is this:

All of the differences between the two, if equaled out by adjusting spring length and pin travel distances, I don't believe will allow my spearmental triple to drive with as little spring pre-load as this V-3 can.


And the other is this:

For whatever reason(s), this V-3 is producing as close to the "perfect" rimfire ignition, as is possible today, with only 8 pounds of firing pin spring pre-load.


Your friend, BC


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I want to add a PS:


I keep saying we're in uncharted waters with this new V-3.


On my triple spearment, I've slotted the trigger hanger so I can actually get .205" of firing pin travel.

But..........

At .205" of pin travel I have extremely hard bolt closing....way too much to deal with during a match.

I've got the pin travel backed down to .190", which is more than most TCA's are easily capable of.

And even at .190" I have some pre-loading going on as I close the bolt, but it is not objectionable....


On this new V-3, I have .216" of firing pin travel, and the bolt closes like a feather.


This with a Jewel trigger.....

I understand Anthony DiOrio is getting .225" of travel, but maybe he's using a B&A?


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We can only imagine the firing pin spring life when only 8 pounds of pre-load are needed.


Instead of having the firing pin spring compressed .375" all the time in the de-cocked state, on this V-3 we only have slightly more than .100" of spring compression in the de-cocked state.

That's almost a 75% reduction in the compression that the firing pin spring lives under 24 hours a day, 365 days a year.