|
The construction of the Foster slug is weight forward with a hollow base of soft lead that expands so the slug doesn't rattle down the bore.
The fluted "rifling" on the slug, IMO, serves little purpose other than as a marketing tool. The weight forward design is what keeps the Foster going straight.
Brennekes are very hard lead for excellent penetration. Some have a felt wad attached with a wood screw (really) to act as a seal and maybe provide some aerodynamic stability. Some Brennekes have a plastic attachment at the rear instead.
Sabots are designed for rifled bores, and don't always release the slug when fired in smoothbores or (as already mentioned) provided much in the way of accuracy when they do.
|