I had a friend make up a batch of 6.5-284 cases with a straight internal volume. There is a relieved area to acomodate for the bullet inside the case, and the usable volume, with a 140 grain bullet, is around 20 grains of powder, depending on what you use.

Before I try them out, I wanted to find out if anyone has dine this before.

Maybe I'll start with some pistol powder to emulate a 9mm handgun load, or maybe with rifle powder as a full house load and see what kind of velocities I get.

I think I can get 155 grain cast lead bullets which would work better as subsonics, but I will start by using up what I have.

So...is this a bubba idea, or a good way to safely make subsonic loads?

Yes they did this in the late 1800s for match shooting with 38-55s, etc. One version was called the Everlasting Case.
So, not a new idea and it will work.

Just don't eject them hard. it would be shame to loose one

My only concern would be with the much thicker brass, would the case obturate enough to provide a gas seal? You might be in for some blowback if they don't.

There are some commercially available ammo specifically made for silenced weapons - mainly in 308 Winchester.

I have seen these cases, they have a much reduced capacity, so in turn are a lot heavier.

G'Day Fella's,

EXPRESS, my solution to Sub-Sonic loads, in most modern centrefire cartridge cases, was resolved when Trail Boss powder came along.
It really is the Ducks Guts for use in full size cases but not the best powder, for the .300 Whisper/Black Out cartridge!

Hope that helps

Doh!
Homer