I'm a bet slow
 

Thanks for the info, I will never ever try a 300 BLK in my whispers.

I definitely don't want to hurt myself or my barrels. I will stick with my Whisper reloads and stay safe.

Alleycat,

As many times as it has been said, people are still just learning that. It is important to be patient and keep on explaining it.

Check and see ?
 

martineta .. Just get a 220 or whatever size bullet you are going to shoot in 300 BLK and check to see at what length it hits the lands.
I got my 300 BLK from Midway a few weeks ago the first thing I did was pull a bullet from one of them and check to see what OAL was okay .. On my
M1S 300WTF the length was okay .. Try that first before giving up .

300 AAC BLACKOUT hits the lands with a Sierra bullet at 2.270 OAL.