You do know that 300 whisper is a patented cartridge and has NO SAAMI specs. Whereas the 300BLK is similar to the 300 whisper and the only difference can be found in the length of the neck. 300BLK has a slightly longer neck than the 300whisper, A 300BLK chamber will accept 300whisper with no problems. Another problem with 300 Whisper is that there are very few factory loaded options out there for it.
300BLK is offered in both a supersonic and a subsonic offering BOTH to a SAAMI spec.
There isnt a lot of info out there on the 300BLK because it is a very new round only been offered for around a year now ... whereas the 300whipser has been out there for a while. JD Jones owns the trademark on 300whisper.
