To bore or not to bore... that is the question.

[BergerBoy]

Let me let you in on a few things: My father is old school and I was taught by him to cast his bullets and reload.... much of it at a very young age. I remember casting lead bullets at the ripe old age of 10 years old- wanting to play with my friends and being stuck behind a work bench and molten lead. At least my father had enough sense to melt/cast lead outside in the fresh air..... I bet he would go to prison for that crap today!!! LOL!! Child endangerment crap.... LOL... Kids today are next to worthless(most).

Sorry to get off track....
Anyway, point is many people I know bore the flash holes on the cases they reload. It gives you a "better burn" and more "efficient" and all that other ********.... To be honest it makes sense to me. A bigger hole for the primer to ignite the powder/propellent etc... sure. Why not??
Lately I have had a problem with SD and ES so I decided to do a little experiment and check the velocity on my reloads that were all the same- I mean it was not done in a lab or anything but all powders were double weighed and I was as careful as possible to make my little "Red Neck" experimnet as accurate as possible.
So me and the wife head out with the Magneto Speed to the range to take notes/speeds. We didn't even look and/or compare numbers until after we went shooting. Once at home, It was then that started to compare data: To my amazment the untouched flash holes had the lowest SD/ES out of all groups. On average it was %20-%30 less than ES/SD than bored flash holes.

I used: Norma MRP, H1000, 7828SSC with Norma brass and Remington 9 1/2 M. It was 58 degrees and %36 humidity. And the round was a 300 WM with 180gr. 200gr. 215gr. 225gr. and 230gr. projectiles.

I know this goes against the grain and all the old-timers are losing their minds at the moment but has anyone ever done or seen a corilation between SD/ES and flash holes like this before??? If someone knows of a REAL study that was done on it. I would like to read about it now that it has my attention. If not, I will continue to do my own testing
I have more data if interested.

Thank you for your time.lightbulb

 

[ShtrRdy]

The people who shoot benchrest like to use brass that has a smaller than "regular" flash hole. They start with Lapua brass in .220 Russian and fire form it.

 

[LoneTraveler]

It is like 2 Schools of though on flash holes. 1. Run a reamer in flash hole ream, out and flare out hole so flame from primer hits back of powder igniting it even from the back. 2. Small straight flash hole so flame blows up through powder to the base of bullet With flame hitting the powder mostly from the front. Holds powder in shell case for even burning. The jury is still out on which way is the best for me.

 

[Rich Coyle]

Thirty years ago I made a few cases with a tube threaded where the primer seated. The tube ran up to about 1/4" from the bottom of the bullet. The inside of the tube match the flash hole diameter. The tube reduced the powder capacity so I had to reduce the loads.

I can't remember the results. But what did or didn't happen, I don't remember.

 

[just country]

morning, a man Mr. Tubbs I can not remember his last name experminted (sp) with

this concept to thread the flash hole and install a brass tube in the primer hole. his

findings were were very negative results. the installed tube, he experminted with

difference lengths of tube. to shoot the primer flash further down the case to

supposed detain the flash to burn all of the powder in the case. Mr. Weatherby

same time period came up the case concept of increasing the case shoulder angle,

to increase the powder volume. then when firing a new case the shoulder and

the case base would conform to the chamber and u will get much less stretch to

fired cases.

food for thought hope this makes sense

life member TSRA-NRA life member.lightbulb

 

[BergerBoy]

Thank you guys for your input.
I was hoping I was hoping to find someone that researched flash hole boring and velocities and the corelation between the two. Any info on the subject is welcome.


Thanks again.