300 Blackout subsonic alloy

[old wanderer]

I have a 247gr mold on order from Swede. I will be shooting 1050 fps loads through my silencer. http://castboolits.gunloads.com/showthread.php?t=102895

I am most interested in what would be the optimum alloy to use.

The casting will be a bit more than regular, as I intend to use a pure lead nose section that does not touch the barrel, and the bore rider section should be just hard enough to not lead my barrel, yet soft to get me best consistency between shots.

As I will not be using thousands of these, economy is not the driving factor. It will be shot through an AR15 with a 10" barrel.

I would be interested in hearing what hardness I should strive for. (I do have a hardness tester).

[cbrick]

A true Whisper round, that's great. So many people try to turn the whisper into a high velocity round.

With your stated velocity I would think most any alloy except hard. You could run a soft enough alloy that the pure lead nose would probably be more trouble than its worth. Something along the line of 50/50 WW pure with maybe about 1-2% tin and air cooled should work well and true to JDJ's Whisper concept on target results should be exceptional.

Rick

[leadman]

In my 18" Contender barrel I shoot the 314299, 206grs out of air cooled wheel-weight. Just about the exact velocity as yours and never any leading. I am using surplus WC680 which is very close to accurate Arms 1680.