.30 and .300 Whispers?

I recently picked up a cartridge headstamped “.30 Whisper” which appears to be identical to the .300 Whisper.

Can anyone explain the change in designation?

Same cartridge and case manufacturers?

Certainly the same cartridge as far as my eyes can judge.

As far as I know, the cartridge (which has been around for a good many years) has always been known as the .300 Whisper, and that’s what it’s called on SSK’s website.

The .30 Whisper is headstamped “OPM 30 WHISPER”.

What I meant was do you find the same cartridge manufacurer and/or case manufacturer calling the same round .30 and .300 interchangeably? Does SSK use both terms? Does OPM use both terms?

SSK does not use both terms. I am not familiar with OPM production so I don’t know if they do.

Don’t forget, the Whisper is a wildcat and the manufacturer can call it anything he/she want.


According to the SSK website, “Whisper” is a registered trade mark, so presumably can only be used to describe a cartridge with SSK’s permission.

I can understand that someone could make a .300 Whisper and call it something else, like 300 Blackout (whoops, I didn’t say that…:-)) but the combination of “30” and “Whisper” seems odd, since the SSK site makes no reference to it.

Tony - Maybe SSK has granted permission to use the 30 Whisper moniker? Or the trademark has expired? Maybe OPM pays J.D. for the right to use “Whisper”? Maybe OPM purchased the trademark? That’s just 4 explanations I can think of.

The world of wildcats and proprietary cartridges is a confusing one, IMHO.


there possible it was a missing ? 30 instead of 300