I believe the .300 Whisper is the .222 Rem necked up to .30 caliber, but I'm interested in necking the .223 up there to shoot 168g MK subsonic. Surely this round has already been wildcatted. What is it's name? Anyone got one? How does it work as a subsonic round? Effective range?

TIA...

MKane160

Mike -

The 300 Whisper is the 221 Fireball necked up to take the 30 cal bullets. It allows the use of the 240 SMK in standard magazines.

The 223 Rem necked to 30 cal IIRC is called the .30 Coyote, but I think the case is too long to allow using the 168 and still fit in the magazines.

Also, the volume of the 223 is far larger than what is needed to shoot the 168 subsonic. If you want to shoot the 168 subsonic I would recommend the 7.62 x 25 Tokarev with the 168, it works quite well, we have built both AR-15 and M-1 Carbine in this round.

Thank you, Marty....

MKane160

I had a 30-223 and was lead to believe that it was called a 300 apache - my cannon loads were 125 siera's (12 inch barrel) with subsonic loads being 180gr sierras.
The 125's off the ground were quite impressive - rather like a 105mm howitzer i wuz informed.
In my experience they necked up quite easily, after a bit of experimentation.

Murray