Spurred on by this thread, I went out today and shot my test loads using these cast bullets.
I loaded a total of 27 rounds (that's just how many of that particular headstamp brass I had).
I used VV N-110 powder which has proven itself to me to be an ideal powder for .300 Blackout. When I first started loading for .300 Blackout, I had every powder listed in my loading manual in my bench, since they were all common magnum pistol powders. Some of the powders I have tried for this cartridge are (but not limited to) Lil Gun, H110, CFE BLK, 296, IMR 4227, H4198......................and VV N-110.
With the bullets I have tested, in every case, whether supersonic, or subsonic, VV N-110 produced better accuracy and better standard of deviation. In most cases a LOT better.
So anyway, I tried these bullets with VV N-110 using charges from 8.0 grains to 8.8 grains in .2 grain increments, loaded to an overall length of 2.150".
So the first thing I figured out is that the OAL is too long to fit in my Ruger American rifle magazine
These powder charges were just a guess, so the second thing I figured out was that these powder charges were all faster than what I wanted, other than 8.0 grains.
8.0 grains 1040 fps 15.8 sd
8.2 grains 1073 fps 8.0 sd
8.4 grains 1085 fps 7.1 sd
8.6 grains 1106 fps 6.0 sd
8.8 grains 1115 fps 2.2 sd
The most accurate load was the 8.8 grain load. None of these loads shot very accurately. I would say the 8.8 grain shot maybe 1.5" at 50 yards. Definitely not impressive.
I have found through trial and error (mostly error) that my rifle seems to have an accuracy node at about 1030 fps. So, I am going to shoot maybe 7.8 and 7.6 grains of VV N-110 and see what happens. I am not all that enthused about this based on the accuracy I have been getting but, I have the bullets, so I might as well shoot them up. FWIW: I have shot better groups using 220 grain Sierra Matchkings, subsonic; AT 200 YARDS than what these bullets are doing for me at 50 yards. But, there is a lot more experimentation left to do. And, I guess I am getting adequate accuracy for "plinking" or shooting jack rabbits or something like that. Problem for me is that I don't really plink. I like to shoot paper for accuracy and some long range steel.
I will update the thread as I go (as long as decent weather holds out, I will be shooting).