anyone loading for this puppy?

What are the chamber dimensions?

I rechamber Contender barrels from 35 Remington to 358X444 Improved all the time and have loading data specifically for that round...

Is it one of my barrels? Is it an "Improved" chambering - meaning minimum body taper and 40 degree shoulder angle?

A

What are the chamber dimensions?

I rechamber Contender barrels from 35 Remington to 358X444 Improved all the time and have loading data specifically for that round...

Is it one of my barrels? Is it an "Improved" chambering - meaning minimum body taper and 40 degree shoulder angle?

A
looks like this, 20 degree shoulder

kinda seated this one badly and crushed it a little

Considering the increased powder capacity of the 444 based cartridge, you can use "middle listed loads" for the 35 Remington and then work up from there. Powders like H-4895 and IMR-4350 should give you your best accuracy and velocity loadings. Stay with standard primers and seat bullets out to very lightly touch the lands. Wait until after the rounds have been fireformed in the chamber before you trim them and then, trim them just enough to square the case mouth....

A