Magnum Mini?

There is not an Ackley Improved version of the 7.62x39.
However, that is something I have been thinking of doing myself. Take some of the body taper out of the cartridge and sharpen the shoulder a bit. You could shoot factory ammo out of it with no problem. It would just fireform the brass. Then you can load the brass for a little more velocity. Just something i have been thinking about for my mini-30.

Hey Geno, isnt the 300 whisper a subsonic round? If I am mistaken, could you point me in the right direction to find some info on it?

Buswack, I am aware of the reason for the body taper, but have you looked at the 7.62x39? The taper on that is a bit extreme. I don't mean eliminate it, just take some of it out to give it a taper similar to the .223. With a sharper shoulder, one should be able to increase the case capacity enough to make a difference without compromising extraction, and without eliminating the ability to fire factory amunition.

Cheers Geno!
I love this place! Everyone is so helpful!
Ok.... 300 Whisper is 221 firball necked up to .308. Sounds effective. 2400fps with a 125gr bullet puts it at exactly what the standard 7.62x39 does anyway. (if you go with hodgdons data http://www.hodgdon.com/data/rifle/76239mmr.php )
I shall have to keep searching.....

I shall be quite carefull. Not looking for anything near what .308 can do. Just a little boost to get it a bit closer to the 30-30 winchester (about 200fps, not 700fps). If it can handle pressure test rounds at about 75000 CUP (my local gunsmith tested it with them), it should be able to do this.