.I'm interested in bullet slump/alloy issues also. Decided to test with 2 different bullets and 7 different powders. The powders will be 4227, h4895, 4046, varget, bl-c2, h414, 4350, reloader 19, superformance. The bullets will be a saeco 301 and a lyman 311465, both will be cast from range scrap and pc'd. Another set of bullets will be cast from range scrap (15#) and mono-type (5#) + 2% tin cast *730 and water quenched and aged at least a week. All bullets will be sized the same using the same sizer and the same gc's installed.
Not sure but I figured the fast burning powder/pressure would test the alloy and the slow burning powder would test the rpm threshold. I actually have no set/target group size. Just wanted to see if I could walk loads in and then back out and at what point did those loads/alloys fail.
So far I have managed to to do the testing with the 4227,started both bullets @ 18gr's and took the loads up to 25gr with the 301's and 27gr with the 311465's. At the low end of the load (18gr) it didn't matter with any of the bullets. Groups were the same up until the 23gr/301 & 24gr/311465. Then the range scrap/pc'd bullets gave up the ghost. The hard cast 301's really didn't like the 4227, and the groups stayed around 2 1/2" (outside hole to outside hole) the whole way thru the test up to and including the 25gr load. The hard cast 311456 tightened up at 26gr and started opening up at 27gr.
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I have no idea what the velocities are, need to start bringing the chronograph to the range. The only thing I can come away with with the testing of this powder with these bullets is:
The soft pc'd bullets slumped under the higher pressure loads and their groups were 1+" bigger than their traditional lubed/hard cast counterparts.
The 301 never did anything and stayed the same 2" to 21/2" groups thru out the 18gr to 25gr ladder test with 25gr actually being the best.
The 311465 walked right in and back out again as it should so I believe I'm looking at the rpm threshold of that bullet.
The next powder will be h4895, that should answer the rpm questions and hopefully some of the alloy/pressure/slumping questions. Planned on doing ladder tests until all bullets blowout/fail and then chronograph those loads.
I may have to change bullets and go back and re-test the 4227/long nosed bore ridding bullet. The 301 is a bore riding bullet that has a long slender nose. I never tried the 301 (actually either bullet) in this bbl. The bbl is a .301/.308 instead of a .300/.308 and the 301 bullet's design is real close to having only 60% of the bullet engaging the .300 bore.
Anyway, that's all I know how to do, walk the loads up until they fail to get a baseline of the bbl/bullet/powder. And then change bullet dia/lube/gc/alloy 1 thing at a time to see if the bullet can be pushed past it's original threshold.