Why Whisper Cartridges?

[DesmoDucRob]

It seems to me that nearly everything that needs to be done with a whisper cartridge can be done with a large-bore handgun cartridge, fired at subsonic velocities. A 44 magnum, 50 AE, and 500 S&w can all be loaded to subsonic velocities using heavy bullet weights, so why reinvent the wheel? I'm missing someting, so fill me in. I suspect it may have something to do with compatibility with the AR platform, but if you can adapt an AR to fire 22LR, you should be able to adapt if for the cartridges mentioned above. So fire away; what is so special about the 300 whisper, 338 whisper, 6mm whisper etc?

 

[dzelenka]

It seems to me that nearly everything that needs to be done with a whisper cartridge can be done with a large-bore handgun cartridge, fired at subsonic velocities. A 44 magnum, 50 AE, and 500 S&w can all be loaded to subsonic velocities using heavy bullet weights, so why reinvent the wheel? I'm missing someting, so fill me in. I suspect it may have something to do with compatibility with the AR platform, but if you can adapt an AR to fire 22LR, you should be able to adapt if for the cartridges mentioned above. So fire away; what is so special about the 300 whisper, 338 whisper, 6mm whisper etc?

You are missing the most important thing. The original whisper, the .300, was designed to be fired with a 240 gr Sierra (actually it was a 250 at the time that was discontinued in favor of the 240) at sub-sonic velocities. That bullet has a ballistic coefficient of .685. A .44 Mag bullet of similar weight has a BC of around .230. The .44 starting at 1050fps is going 961fps at 100yds and 898fps at 200 yards. Sighted in at 100yds, it will be 37" low at 200. A 10 mph wind will blow it 2.75" at 100 yds and 9" at 200 yds. In contrast the .300 whisper starting at 1050fps is going 1019fps at 100yds and 993fps at 200 yards (and 969fps at 300 yds). Sighted in at 100yds, it will be 33" low at 200. A 10 mph wind will blow it 1.2" at 100 yds and 3" at 200 yds. Plus the whisper can be easily chambered in common bolt guns or the AR platform with standard bolt faces, magazines, etc. For a subsonic sniper rifle, the whisper is far superior from a ballistic standpoint as range increases.

By the way, the .240 Sierra out of a .300 whisper tends to yaw significantly in flesh and create significant wounds (bullets passing sideways through things frequently do).

Dan

 

[peterf225]

Because there is ZERO recoil and just a blast to shoot. My 300 whisper doesn't move a bit when I fire it and I am shooting it super sonic off a bipod. The round looks cool also, the bullet is almost bigger than the case itself.

 

[DesmoDucRob]

You are missing the most important thing. The original whisper, the .300, was designed to be fired with a 240 gr Sierra (actually it was a 250 at the time that was discontinued in favor of the 240) at sub-sonic velocities. That bullet has a ballistic coefficient of .685. A .44 Mag bullet of similar weight has a BC of around .230. The .44 starting at 1050fps is going 961fps at 100yds and 898fps at 200 yards. Sighted in at 100yds, it will be 37" low at 200. A 10 mph wind will blow it 2.75" at 100 yds and 9" at 200 yds. In contrast the .300 whisper starting at 1050fps is going 1019fps at 100yds and 993fps at 200 yards (and 969fps at 300 yds). Sighted in at 100yds, it will be 33" low at 200. A 10 mph wind will blow it 1.2" at 100 yds and 3" at 200 yds. Plus the whisper can be easily chambered in common bolt guns or the AR platform with standard bolt faces, magazines, etc. For a subsonic sniper rifle, the whisper is far superior from a ballistic standpoint as range increases.

By the way, the .240 Sierra out of a .300 whisper tends to yaw significantly in flesh and create significant wounds (bullets passing sideways through things frequently do).

Dan

Thanks, Dan. The difference that I was considering to be of little significance actually appears to be magnified downrange. I did not realize that the two 240 grain bullets had such a different BC. I was assuming that a 44 magnum could be loaded with a bullet of similar weight and profile, and get similar performance. ...guess not, -off to the reloading manuals with my thinking cap.