I got my theoretical weight by first using the twist calculator at
http://kwk.us/twist.html to get a.312 dia lead bullet at 1000 fps out of a 1-8" twist barrel to get a maximum length bullet of 1.37". I then used the mold designer at
http://www.mountainmolds.com/ using the defaults as cast .312 dia bullet the weight of 265 grains is 1.368" to 1.381 long. This is just the preliminary weights. I know the weight will change with bullet design but its a starting point.
This will be a strictly subsonic bullet. From what I have learned over the years at subsonic velocities the nose design is not of great concern as it is in supersonic bullets. This is why full wad cutter bullets are used in pistols for extreme accuracy in bullseye revolvers. Unfortunately wad cutters don't feed to well. I want to keep the shape as close to a cylinder as possible to get maximum stability and weight. I have to do some mock ups to see what will feed the best in most rifles and still give me what I want. I am thinking the nose shape like the Lyman #311284 or like the Saeco #311 Truncated Cone. I have to try both shapes to see what works the best. The most important thing with subsonic bullets is the base, since this is were most drag is created in subsonic bullets. It will not have a gas check as at 1000 fps they are not needed. It will at least have a bevel base bullet for ease of loading and a little less drag. I am thinking of trying a rebated boat-tail since this has proved to be the best in jacketed subsonic bullets. The rebated boat-tail also moves the center of gravity forward which is what you want. It will probably be a bore-rider bullet.
I want to keep the price point under $10/100 sized and lubed. I want to keep them as cheap as possible but I also want them to be very accurate as well. This is the first bullet I am designing so if anyone has useful information please share it. It would be nice to get it right the first time.
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