primer pocket cutting

[7mmRHB]

JB, how much thickness variation was there from side to side on the necks? Were they thicker at the base than at the mouth?
Did the variation show up on the measurements of the loaded rounds measuring completely around the neck?
Was the amount of bullet run out effected by the neck wall variation?

The best lot of 6br norma brass from Lapua that I have ever match prepped was 5 to 7 ten thousanths fromside to side and more than that from base to mouth. Most lots aren't that good!!!
The flash holes are generally to deep to do anything more than just touch the corners anyway.

How many brass did you start out with or are you just useing it (as is) without sorting?

Sorry to ask so many questions but I'm very interested in the methods you're testing and the corresponding results.
I'm assuming you will try some full match prepped brass from the same lot to prove your therory that you don't need to spend all that time prepping brass.---RHB

 

[jb1000br]

[ QUOTE ]
JB, how much thickness variation was there from side to side on the necks?

ONLY MIC'D A FEW...UNDER 1 THOU IIRC...HAVEN'T FELT THE NEED TO EVEN CHECK FURTHER WITH THE WAY IT IS SHOOTING...BUT I WILL WHEN I GET SOME FREE TIME.

Were they thicker at the base than at the mouth?

WHEN I MIC NECKS I KEEP THE ANVIL EVEN WITH THE END OF THE NECK, SO I NEVER MIC THE BASE OF THE NECK...

Did the variation show up on the measurements of the loaded rounds measuring completely around the neck?

LOADED RDS MIC AVG .2695...NOT SURE ON MAX/MIN

Was the amount of bullet run out effected by the neck wall variation?

THE COUPLE I CHECKED WERE UNDER 0.002 TIR

The best lot of 6br norma brass from Lapua that I have ever match prepped was 5 to 7 ten thousanths fromside to side and more than that from base to mouth. Most lots aren't that good!!!
The flash holes are generally to deep to do anything more than just touch the corners anyway.

YOU MEAN THE PRIMER POCKETS?

How many brass did you start out with or are you just useing it (as is) without sorting?

300...WEIGHED AND SEGREGATED IT IN A GRADIENT WITHIN 50RD BOXES...NEVER MORE THAN .5GN SPREAD IN A 50RD. BOX THOUGH.

Sorry to ask so many questions but I'm very interested in the methods you're testing and the corresponding results.
I'm assuming you will try some full match prepped brass from the same lot to prove your therory that you don't need to spend all that time prepping brass.---RHB

[/ QUOTE ]

RE: MORE TESTING

I was going to test each individual step agains each other: neck turning, FH reaming, FH deburring, PP reaming...BUT I dont want to waste the rounds to do a proper test, so running my totally UN-prepped cases agains totally PREPPED cases might be feasible.

tentative plan:

10 shot groups at 1000yds in hopefully benign conditions...or 300-500yds if i cant do it right at williamsport.

prepped:
neck turn
FH chamfer without opening the FH
PP ream

Run 10 shot groups against my unprepped...if any appreciable difference, then start picking apart the prep steps to see where the most gain came from...

I'll try to get the measurements you asked for...I have about every other dim, but the ones you wanted...

JB

 

[7mmRHB]

Thanks JB ,It was real late when I was posting ,hence the brain fart on the primer pockets. It will be interesting to see this process unfold!!

Are you sizing the full length of the neck or just a portion of it?

Good luck in your matches-----7mmRHB

 

[jb1000br]

Sizing is with a Harrell custom die...hardly touches the shoulder and moves the web a little over 1thou

.267 bushing NO EXPANDER (gives .2682 diam oddly)

they have the die made so that the bushing gets MUCH closer to the shoulder than on a redding. Nearly as if it was a non-bushing die...I was impressed. The die is beautiful and lets the bushing float in the cavity.

so basically 99% of the neck to answer your Q.

O yea...FL sizing with 1-1.5thou shoulder bump

JB