sorting by empty case weight?

[Wild Bill IV]

You make a good point where getting the cases as uniform as possible from fire forming and case prepping before weight sorting (e.g. case fully fire formed, removing flash hole burr, turn necks, cases trimmed to a consistent OAL, chamfering, etc.). Then you get a better measurement of case weight to volume by taking a lot of noise out of the data. And that's what I've done when compiling my data.

When you mention the "humping or cratering around the primer pocket" from the manufacturing process and that you filing the base flat, I would think that if there's enough of it, the firing forming would take care of that as the base is pressed against the bolt face during firing. . .???

BTW: When deburring the flash holes, I've found the 21st Century tool is the best since it doesn't put any kind of chamfer in the hole like so many tools do and trims away the burr making a nice uniform flat area around the hole. I've often heard it said that it's not necessary for the Lapua brass. Though I've found it to be not much of an issue with my Lapua brass, I have found there are always a number of cases in a batch that I get substantial filings removed. So, I always run that tool in all my Lapua brass to be sure they're all taken care of. It's only a one time operation, so . . . why not.

I file the bases before running down the primer pocket uniform tool to have consistent primer pocket depth!!! After all, the uniform tool has a depth stop step that contacts the base itself and stops the cutter from going deeper in the pocket!!. Plus, having more surface area, reduces brass movement!! Even the head stamping causes some irregularity that I have notice when filing bases!!! I prefer to start the full fire forming with uniform primer seating and a flat square base for the high pressure forming of the case!!!

On the subject of inside flash hole chamfer tools, I use the Sinclair tool!! Not only does it chamfer, it also slightly enlarges the flash hole itself (uniformity and consistency)!!! ANOTHER VARIABLE THAT AFFECTS THE WEIGHT/VOLUME DEBATE!!! On Lapua brass, it increase the diameter slightly!!! I have some virgin Lapua brass, and I am going to pin gauge before and after to see the variation of the flash holes!! However, other brass manufacturers have higher variability in flash hole diameters!!! I know for a scientific fact (physics fundamentals), that variation in the hole diameters will slightly increase the ES and STDs!!! Plus, I like a slightly larger flash hole because it will increase the force on the primer and will show high pressure signs sooner on approaching peak powder charge!!!! The slightly larger diameter will also allow slightly more FLOW of the primer flash!!! More flow, better powder ignition!!! With the slight increase of flow, more heat is affecting the powder!!! More heat will overcome the phase change energy requirements faster (in this case, the amount of heat needed for the solid powder particles to turn into a gas)!!!!! This in turn, reduces the severity of irregularities in the smoothness of the pressure curve which improves the efficiency!!! The more efficient, the more consistent!!! THE NAME OF THE GAME IS CONSISTENCY WITH ALL COMPONENTS OF THE RELOADING PROCESS!!!!

CAUTION: DO NOT INCREASE THE FLASH HOLE DIAMETER TOO MUCH!!! TOO LARGE A DIAMETER CAN CAUSE PIERCED PRIMERS (RELEASING CORROSIVE GASES THAT WILL ATTACK BOLT COMPONENTS AND CAN BURN EYES, NOSE, AND/OR THROAT), ENLARGE PRIMER POCKETS, DAMAGE TO THE FIREARM, AND/OR HUMAN INJURY OR POSSIBLY DEATH!!!!!!!!! STAY WITHIN SAAMI SPECS!!!!!

In engineering physics, p (pressure) = F (force) ÷ A (unit area).
By multiplying both side of the equality with A, the formula is now:
F = p x A (in this case the area of the flash hole).
Holding pressure as a constants yields the following statement:
As the area increases, the force will increase proportionally!!!
The primer and the primer pocket can only sustain so much FORCE before they are compromised!!!