Twmaster wrote:
Ok, not to sound too goofy here...
But isn't it a bad idea to have a gas checked bullet seated below the neck?
Not a problem, believe me…I thought of that before loading them.
The Beartooth bullet has a BHN of (21) so we need right at 30,000 psi in order to obturate the base of the bullet.
The copper gas check (crimped on BTW) has a BHN of approximately (40), so over 50,000 psi necessary for it obturate (expand/change shape).
The SOCOM is limited to 35,000 psi (MAX) so its impossible for the gas check to “grow” in size. It can only be pushed into the base of the bullet which does obturate slightly with most loads.
As long as the gas check does not come off during the seating process (ever try to pull a crimped on gas check off) then I have nothing to worry about at the pressures I run.
So long as the gas check is reasonably square to the base, it has nowhere to go except against the base of the bullet. The high pressure from the gases insures this.
Typically…the speed of most modern propellants (while expanding) exceeds bullet speed by 3-5 times. Trust me…the gas check WILL be firmly planted against the bullet base.
As long as the gas check does not obturate (grow in size) while below the cartridge neck (bottle necked cartridge) then there is no concern.
Additionally, I do not roll crimp the cartridge into a cannelure, I use a LEE FCD to very lightly apply a “squash” crimp to the entire neck of the cartridge. Not enough to deform the bullet, just enough to create some tension.
Remember the entire cartridge case expands as pressure rises (it literally sticks against the chamber wall until pressure subsides and the brass springs back a bit). Internal cartridge specs are getting 'bigger', not 'tighter' under pressure, the exception being slight cartridge stretch towards the last part of the pressure curve.
No pressure spike will be created by the gas check in this cartridge…at the pressures I run.
There may be examples (with some loads), (in some bottle necked cartridges) where someone gets
everything wrong and potentially creates a problem for themselves, but not here.
Good question though!
Flint.