Fast action

[Tim Singleton]

A little bit of an unusual question.
I have two Bat DS actions in Scoville stocks one of them is 50 fps or so faster than the other. Im shooting a 6ppc
Since i have had my Garmin mounted for every practice session for several weeks.
I have noticed one gun is faster than the other. I am loading at the range where 29.7 of 133 gives 3400 to 3420 in the fast gun.
The other rifle is 3360 to 3370. I have to load 30 grains in the slow gun to reach the same velocity
I didnt think too much of it thought well that just a faster barrel. I have tested two other barrels since getting ready for the Shamrock. The one rifle is continually faster. So then I put the slow barrel on the other rifle back to 50 to 60 fps faster

So, is the firing pin energy a little higher on the faster action?
Has anyone else noticed anything like this?

It doesnt really matter much just something I have noticed with the Garmin on every shot I make
Im beginning to think that the faster gun is agging better than the other which is how i have came to the thought of the pin energy thing. More testing to do, to come to a firm conclusion on which gun aggs the best

 

[Alex Wheeler]

Yes, ignition can do that. 50 fps is a lot but I guess its possible. The easy way to answer the question is to swap bolts and see if the velocity follows the bolt. Dont just swap firing pin assembly's, do the whole bolt.

 

[jackieschmidt]

Check your firing pin spring’s static pressure and see if one is higher than the other.

Like Alex said, the entire bolt assy is involved in ignition. Swap them out.

 

[Tim Singleton]

Yes, ignition can do that. 50 fps is a lot but I guess its possible. The easy way to answer the question is to swap bolts and see if the velocity follows the bolt. Dont just swap firing pin assembly's, do the whole bolt.

Yep, I was thinking about that
I will do that this Thursday and report back

 

[JSH]

I guess I may be the only one that will ask. So how does faster firing pin drive up speed?

 

[Alex Wheeler]

I guess I may be the only one that will ask. So how does faster firing pin drive up speed?

How the primer is hit effects how it ignites the powder.

 

[JSH]

Is that impact speed or closer to center? Or a combination of the two.

 

[Alex Wheeler]

Its a combo of stored energy, time, and mass.

 

[Loggins J]

Yep, I was thinking about that
I will do that this Thursday and report back

Very interesting I would like to know what you come up with

 

[Tim Singleton]

It does seem like its following the bolt

 

[liljoe]

Did you try just pin assembly Tim?
Joe

 

[Alex Wheeler]

Its amazing the effect ignition has isnt it?

 

[Tim Singleton]

Did you try just pin assembly Tim?
Joe

Nope just swapped bolts. Ill try just that next

 

[LVLAaron]

I love when the things that get talked about all the time can be demonstrated so easily.

 

[pew_pew]

This is really cool to see. It would be amazing if you could identify exactly which part/s of the bolt that contributed to the difference the most.

 

[Tim Singleton]

This is really cool to see. It would be amazing if you could identify exactly which part/s of the bolt that contributed to the difference the most.

Speedy worked both of them over
may never figure out what is different.
pin fall is about identical protrusion is the same spring pressure seems to be the same.
Ive got another barrel to test I’ll try it on both guns and see how that goes
ive got some 040 ball bearings ordered to measure the depth of primer indentation

 

[Jim Ziegler]

Any difference in accuracy between the 2?

 

[Tim Singleton]

Any difference in accuracy between the 2?

Still havent quite decided but after i swap barrels back again ill decide.

 

[Tim Singleton]

The pin protrusion is the same on them both at 055 but he had to make a face cut on the faster one to get it

 

[muleystalker]

Since he had to make a face cut on the one firing pin have you thrown the firing pins on a scale and see what they weighed? Might the faster one he had to face cut be lighter.......