I'm contemplating getting or building a new bolt action ; what are the relative merits and problems of the 300 Whisper (subsonic) vs. the 45 ACP?
I understand that bullet shape can make a difference in ballistics at high speeds, but at speeds <=1000fps, does it really matter that the 300 Whisper is a spitzer or spire and the 45ACP is a relatively flat roundnose?
Does anybody use supersonic cartridges in their 300 Whisper? If so, why not just get a .308 Win bolt action? Subsonic loads can be bought or made for .308 Win and ammunition is more readily available...
FWIW, I do not have anything in 308, 300 whisper, or 45ACP at this time.
I have 300 whisper on an AR platform which the only part different is the barrel - uses cheap mags/parts etc and functions semi auto!
- the major advantage is that you get both High velocity 7.62x39 type performance and the Quiet 30 caliber heavy bullet subsonic (240 SMK or 220 SMK) that retains the velocity better than the 45 caliber bullet for longer distance shooting.
You'll find that your not going to get expansion with those bullets but if the target is thick enough the bullet will swap ends which does create a good wound. I'm currently doing research for 308 subsonic in hopes of finding one that will cycle either HK, FAL or M14 but I've been told not hold my breath.
I also have 45 caliber autoloader with a can and I honestly think for close in shooting it has more effect.
You are correct that 300 whisper isn't found at the Big Box store like 45 ACP is, not hard to make if you handload - just need dies and 221 fireball brass - more work to make them out of .223/5.56 brass but can be done.
I've been counciled by several people to research 7.62x39 as host for 30 caliber subsonic ammo and see they are offering 154 gr bullet loads but nothing subsonic yet.
As for building bolt gun in 45acp, I see stuff advertized but haven't see much out at the range - 90% vaporware it seems to me, but if you can perserver I'm sure you'd be happy with it for close range work.