Originally Posted By: StobA word of caution. I chambered a 300 Blackout for a friend. I don't know what bullet or powder he was using, but while he was working up a load, he said there was a fine line between getting the bullet out of the barrel, and keeping the bullet subsonic. Just keep looking down the bore and make sure it's clear.
your friend is only right if he's doing load developement like an idiot - or trying to work with a powder thats way-way-way-way off the ranch - which goes back to my previous idiot comment.
theres a LOT of room - at LEAST 150-200 FPS ( and thats conservative, but not worth mucking about with further than that far below subsonic for safety reasons) - between subsonic and a stuck round in the blackout. and LOTS of known good powders to use for subs that will keep you well out of trouble.
thats also why when developing subsonic rounds you start high and work down until you get your subsonic load, instead of starting at a min charge and working up like you do with supersonic loads. and also why you use a chronograph so you know when to stop the downward well above where a stuck bullet will be an issue.
so while i applaud your words of caution - please stop spreading misinformation about a caliber that excells at doing things in the subsonic realm and able to do so safely when following proper reloading protocols.