there is another way to boost velocity and still have the bullet close to the rifling for accuracy
The +P stepped rifling does work to lower initial pressure spikes & allows you to work up to higher velocity as you bring the pressure up
Added a throater to the order I made yesterday for just that reason. Going to do 1:12 and 1:16 barrels as tests... start with a 28" blank and cut down as a test also. Work out the nodes kinda thing.