gunsmithing, ammunition-reloading, saamiSAAMI defines a wide variety of parameters for firearms, including maximum pressures for a given round (eg 60,200psi for a .30-06).
If I were building a custom rifle and wanted to increase the performance of fired rounds, would increasing the pressure behind the bullet achieve this?
For example, if 55gr of a given powder will generated 57kpsi, but I’d like to go to 68kpsi, and adjust my powder load accordingly, what will need to be done to the receiver/barrel/etc for the higher pressures to be handled properly?
Will increasing pressure behind the bullet give a better performance in terms of velocity, range, and accuracy? Could it hurt any of the above?
What other considerations would need to be made to effectively wildcat an otherwise-common round (and still allow the rifle to shoot factory ammunition)?
P.O. Ackley is the one of the definitive experts on wildcatting, considering he was one of the developers of the .22 Eargesplitten Loudenboomer cartridge (.380 Weatherby Magnum necked down to .224, pushing a 50gn bullet). A good resource would be his Handbook for Shooters and Reloaders (volumes 1 and 2).
Assuming your receiver and barrel are made of unobtainium, your biggest concern will be the barrel's twist. @Bryson has a fantastic guide to twist here. If I'm reading it correctly, given some bullet weight/length, optimal twist increases with muzzle velocity.
Once you've solved for twist, the problem remains of designing a receiver and action that can handle your increased pressure. Falling Block actions tend to be very sturdy, and are therefore unlikely to blow up in your face. I'm not very well versed in metallurgy, but you'll probably want a chamber and barrel milled out of one piece of billet carbon steel. You'll have to throw that out occasionally, because higher pressures will accelerate throat erosion.
In order to increase accuracy at range, you can fiddle with bullet design. Accuracy goes to hell when the bullet crosses the trans-sonic barrier, so decreasing the coefficient of drag and increasing weight (while keeping muzzle velocity constant) increase effective range.
Good luck and don't lose an eye!
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