OzFclass

Hi All,
Filling in this COVID time!
Just looking for a bit of input. Anyone who knows anything about photography and F stops welcome.

High speed video

The link will hopefully take you to a youtube video of 3 consecutive primer tests. These were all using a primer I expected to be consistent and it looks like they were. To take these I turned the F stop to 11 as a means of "seeing through" the smoke. With the Fstop anything higher than 8 all you see is a smoke plume. It's pretty but not particularly enlightening. These, I hope, are showing the ignition that hits the powder.
From here the aim is to run the same test with flash holes that have been chamfered. Then run different primers and see how they compare.
On Small Rifle I'll do the same and also see the effects of turning a SR flash hole into a LR flash hole.

I've no idea where it will take me, prove theories, dispel myths, who knows.

Here is the test rig, basically a Lee shell holder with a firing pin running through it mounted in a hammer so I can achieve a consistent force.
The case is just a winnie LR cut back to the head. I did run some tests with about 3/4" of case wall but figured I wasn't seeing what actually came out of the flash hole (shape of flame front) so I trimmed it back.





I'm using a Chronos 1.4 camera running at 17500 fps. Just for reference these clips are between 12 and 15 frames long so it's all going on pretty quick.
I am making this up as I go along so any advice or direction is more than welcome.

Feel free to disclose the primers your testing and the batch numbers please Tim

Brad Y wrote:Feel free to disclose the primers your testing and the batch numbers please Tim

I will do Brad, These were just some Fed 210s (because I have a load) for setting up and testing the gear.
The idea is to get a testing process set up so all tests are the same and can be compared to one another. I would rather get that done right before I start for real because the video editing is the bit that takes time.

Be a great time to test flash hole size, also a set of additional weights for the “hammer” as I’ve found value in admittedly limited testing of tuning firing pin spring strength, flash holes can be “shrunk” with a simple punch, good on you for attempting this, the photography and youtubiness is beyond me

Rich4 wrote:Be a great time to test flash hole size, also a set of additional weights for the “hammer” as I’ve found value in admittedly limited testing of tuning firing pin spring strength, flash holes can be “shrunk” with a simple punch, good on you for attempting this, the photography and youtubiness is beyond me

Running the hammer at 30 degrees for these tests. I can up that to 45 and 90 to see if there is any notable difference from hitting the primer harder. I can probably measure the firce applied as well but will need a sensor for the Fluke.
I've never thought of shrinking the flash hole. I've already got some SR cases ready to go. One with a small flash hole and one with large. We'll see how they go.

It comes from a black powder book by Paul Matthew’s on BPCR silhouette, converting 45-70 cases to SR and .060 flash holes to reduce ES

Still getting my set up right. I put graph paper behind the results (1" with 1/2" sub divisions) and ended up back lighting that to reduce the visible smoke.

I only have 2 LR primers on hand, Fed 210 and S&B LR. So far both seem very consistent but there is a notable difference between them.