Anyway, I had five loads to try out. Load data for the 470 NE is not exactly plentiful, and data for cast loads is practically non-existent. The folks at Accurate were very helpful with supplying data for 5744, which was what most others seem to be using for cast bullets in this monster.
I loaded four each of five different charges of 5744 with my cast bullets. They were just air cooled wheelweights from my custom mold I designed and had Mountain Molds cut. The bullet is 500 gr. gas check design with a 70% meplat.
It was interesting to watch the regulation come together as the velocity increased. Some other guys had reported their doubles regulated well with 45.0 gr. of 5744, but that is a very mild load and I wanted something more mid range, so I started at 48.0 gr. From my results, I don't think my rifle would like 45 grains anyway. As you can see, the lighter loads actually had the barrels crossing.
I shot two from each barrel at each target off the bench at 50 yards. The sweet spot was found with load #3. Two shots from each barrel measuring just 1 5/8"
Load #1) 48.0 gr. @ 1500 fps
Load #2) 51.0 gr. @ 1610 fps
Load #3) 54.0 gr. @ 1751 fps
Load #4) 57.0 gr. @ 1849 fps
Load #5) 60.0 gr. @ 1960 fps
After I reached the 57.0 grain load I think the pressure may have been starting to break down my alloy, because the regulation still looked pretty good. Accuracy from each barrel just began to open up. I'm going to try those last two loads with a #2 alloy and see if they tighten up any. Although I'm tickled to death with the #3 load, I'm somewhat disappointed that it was that easy to stumble on a good reduced load. I say reduced, but that dude has about all the recoil I would want for punching paper. Should make a dandy whitetail load too. Don't laugh, bambi's in deep trouble this year.
After I got home I inspected the bore. Not a trace of leading, just some light streaking that a couple wet patches took right out.
Overall a very good trip to the range, and one I've been anticipating for a long time.
I guess the next project with be to come up with a full power load (2150-2200 fps) using RL-15 and my cast bullets with a harder alloy.
