Join Date: Jan 2011
Location: Ridgelines of Virginia, Roanoke Valley
Thanks, pdkfising, for pointing out the added accuracy potential of an improved chamber and the preference of rimmed cartridge design in break-actions.
I have some improved chambers that have been cut to accommodate the rim of the new parent case (.358x444Imp, utilizes shortened 35 Whelen Imp. dies).
I'm constrained to the pressure tolerances of the contender, and I try to be ever-mindful during my selection of loadings.
Determining PSI/CUP conditions upon firing a given formulation of components is not always an obvious conclusion.
Seating long and using resistance of rifling to compensate for misgiven headspace can result in pressure spikes, more so with jacketed bullets than cast I would think... but I shoot predominantly jacketed.
Perhaps I need to utilize more cast and slow my roll.
Now for the crux of my situation, I’m shooting the 250 Savage.
I know that it’s dabbling on the dark side when it comes to the contender and it's tolerances to breech thrust.
But it can be safely loaded for the platform. The Ackley version of the cartridge becomes even more attractive in regards to pressures.
Even the fire-forming of factory brass relieves a bit of pressure in the process as cited by Bellm in the article on the 300 Savage use in the contender.
The SAAMI pressure for the 300 Savage is 46,000 psi while the 250 Savage is only 45,000.
I only use loads that will generate only 39,000, and I figure, correct me if I'm wrong, if I cut the chamber to an Ackley shoulder and more parallel walls that I would enjoy an even more relieved pressure upon firing same component loads.
I'm open to ideas.
Think twice, shoot once...