Lee in a Texas -
Howdy !
I did some math and sample .224” cal wildcat case forming.
Want to see how close to 52gr case capacity I can get, using 9.3x62 as parent brass ; and keeping case oal to < 1.920” .
52gr is a pretty healthy H2O capacity for a .224” cal cartridge , w/o being as “ over bore “ as larger capacity wildcats; like .22-6mm Remington.
An example .223WSSM case, while only 1.670” long; requires base and shoulder diameters of more than .540” to realize a case capacity of 52gr H2O. So, what capacity is possible.... forming from 9.3 x 62 basic, and
exploiting shoulder diameter to get maximum capacity w/ a case 1.910” lg?
Sample wildcat cases I trial formed showed that with an unfired base diam of .474”, shoulder diam of .464”; 26* shoulder angle, and one calibre neck lg; it would take a case 1.950” to hold 45.5gr of trial IMR 4955 powder.
A .223WSSM used as a standard for comparison, can hold and safely shoot larger wt charges of slightly faster burn rate H4831 and HV100
powders. Conclusion: No...... you can’t get 52gr H2O capacity in a case 1.910”lg..... and w/ .010” case taper; when forming from 9.3 x 62.
I appreciate that 6.5 X 55 has a more-generous base diam than does 9.3x62, but I intended to go w/ a .473” base diam; and the Swedish case is larger in diam.
With regards,
357Mag