20 gauge-- Fired factory 3.5" plastic cased Hastings 395 gr
locked on sabot slug in 20ga with 30 inch barrel and
got 1900 plus fps. Same sabot slug in RMC 3.5" brass case
with shotgun primer, got 2500 fps. Case bases didn't
expand. Load of 150gr RE17 slow enough getting to
peak pressures is easy on cases. Dies work with
both case types.Ed