1. At how high a muzzle velocity can you launch a powder coated cast bullet (following load tables of course)?
2. What BHN is needed, or optimal, with the high velocity?
I am asking these questions because in an effort to improve trajectory, to delay transonic effects, and to improve bullet stability, I tried increasing velocity by shooting 405g commercially cast, conventionally lubricated bullets, at 1500 to 1600 fps velocites.
The results were bad: no grouping whatsover right from the first group fired, and sure enough, when I checked the barrel condition afterwards, I had, for the first time ever, lead fouling of the barrel, and a LOT of it. It took me 1.5 hours to get it out via chemical and patching and brushing.
This is despite the fact that I had been shooting 464g to 500g powder coated bullets at up to 1400 fps with NO leading whatsoever. In fact, only unburned powder fragments in an otherwise pristine barrel. Those 464g to 500g powder coated bullets actually produced groups as good as 0.8 MOA at 150 meters = 164 yards. But, that's a s fast as the load tables will allow, so if I want to go faster (and I do), I need to know how fast powder coated bullets can be driven and what BHN constraints, if any, apply.
So, I am wondering if I could get a mold that produces a lighter weight bullet (say 400g or thereabouts), powder coat the those bullets, and launch them at the higher velocities that the load tables say are permissable and achievable with those lighter weight bullets, and see what accuracy I can get.
The usage would be purely paper target and steel gong targets. NO hunting, so expansion or brittleness don't matter.
Jim G