Got asked about slugs going from supersonic to subsonic.I understand
it is that blunt bullets that are in most shotgun slug/sabot loads,
do not maintain best accuracy when passing back under the speed
of sound like spire point bullets do.Speed of sound about 1150 fps.

Now on, FED 239 primer in 8bore and the 4bore cases I have
with shotgun primers. They almost as strong, from my primer tests
as the kiln primers from WIN and REM.And they seem to dent easier
in my 8ga testing than FED209 or the REM kiln ones. I get them from
the 3.5" 10 and 12ga Fed primed magnum cases. Makes ignition surer.

Lotta guys want to try Magtech 2.5" 12ga cases. Well they are
stronger built than any of the old time brass cases I have seen.
About dollar each, go in same chamber as plastic, same strength.
The rifle looking cartridge in a slug gun is what some like..
If you have break action load them with protruding slugs any length.
If auto or pump in 3.5" chamber load them up to 3.1" overall
with protruding slug and you can feed from magazine.
RCBS has sizing dies. Ed