It's no mystery to any of us that enjoy shooting magnum handguns that forcing cone erosion is a very real reality. It is most commonly seen with double base spherical powders like W296/H110, 2400, or the most infamous, Lil'Gun. Here recently I've been doing some load development with H-Lil'Gun out of my BFR 44 Magnum trying to get a load I'm happy with for deer hunting. Now, knowing me, I'm still going to settle with my 270gr bullet over Unique moving about 1200fps, but the Lil'Gun is fun to play with, but I'm finally starting to see very early signs of forcing cone erosion. It's just discoloration for now, nothing serious, but it had me thinking.
Accurate has a powder known as 5744. Many are familiar with it, as am I. There was a time where I was burning 8 or more pounds of it in a year. I have load data for this powder for the 44 Magnum and 45 Colt (Ruger/TC/FA only). 5744 is a double base, extruded powder that sits on the burn rate chart not far from W296, on the slower end. Now I reckon, it would probably work better in a longer barreled rifle, but it is not position sensitive and most certainly doesn't require a magnum primer.
What are the odds that forcing cone erosion would be reduced, or eliminated altogether by using a double base, extruded powder to reach magnum velocity and pressure, vs sand blasting it each time with a double base spherical powder. Has anyone tested this? I'll be trying it next time I hit the range out of my BFR. I will try to get my hands on thermal imager to measure barrel temp and compare it to lil'gun.