If you want to hedge your bets towards a combination that WILL work
Pick KNOWN entities... Bullets, Brass Powders, Barrels and other components that successful shooters use and make work. You can fart around with factory stuff that may or may not perform well (most are adequate but not spectacular)
Here is an example. I just went to make sure my go-to 6BR works in -15
175M (Off my back porch)
6BR - a KNOWN accurate and easy to make work cartridge
Varget Powder - KNOWN to work extremely well in 6BR Norma
Sierra Bullets - KNOWN to be an easy-to-make-work bullet
Krieger Barrel - 'nuff said
Nesika Action - KNOWN to be straight, and tough, and handles high pressure cartridges.
Mick McPhee - if it aint right he won't work on it, or he won't hand it over.
Start with a bullet at the lands, and work up from 30 grains. If you cant find a load in 20 rounds, throw the gun away.