Funny story some may find interesting:
One of my favorite 'fun' guns is a Browning B78 heavy round barrel that was originally chambered in 6MM Remington. At some point, it was set back and rechambered to the 6MM Jet....which is based off shortened 307W brass. When f-formed, it becomes what's essentially a shortened 243 Ackley with a rim.
And the 307W cases aren't exactly stout, given the rifles that are chambered in that cartridge. After making these cases and f-forming them, the primer pockets don't hold up real well.
I can push any primer brand I have in with heavy thumb pressure. Yet they've never leaked, despite all the cases having been fired 30+ times. I do a final seat with with a Lee Auto Prime tool to compress the anvil enough for consistent ignition.
Too funny! -Al
