Thread: Attempting a new .224 wildcat

Originally Posted by wsm junkie

@Wingman what causes the shiny rings at the shoulder? Are they just chamber marks?

@wsm junkie no, not from the chamber, that is where the old 30 degree shoulder used to be on the 6.5x47 Lapua..
I short size the case neck to create a false shoulder for the cartridge to headspace on along with annealing to encourage the shoulder section of brass to migrate forward rather than the base of the case to migrate rearward to meet the bolt face which thins the brass in all the wrong places and can cause case head separation. The new 40 degree shoulder is blown forward 50 thou leaving the old elbow imprint of the angle slightly visible as shiny polished rings in its now straight wall. It generally smooths out after the second firing or in the media tumbler.
It is very visible in that pic as that case had just been made and fireformed with trailboss and capped off with wax. A full case of trail boss is not quite enough pressure in this case to blow the new shoulder angles out really sharp but the next load with a projectile does.