Thanks to rattler on 24hr forum for the old time pictures,
above, and the guys really like them. Quite interesting.

Many have success with all kinds of high-power slug designs and
with extra power, have pushed the reliable range of 12ga slugs/bullets
from 75 yds to over a 150 yds. ...Here is picture from a 1926
Manton catalog showing, 1st picture, many brass case old time slug loads.
Notice the 20bore and 12 bore ones with pointed slugs, seems
as ideas to hotrod 20s and 12s are old hat, not as strong as 12ga FH ....
Both Pictures below from lancaster and CptCurl on Nitroexpress.

2nd picture are saboted slugs, called the SAGA, from Spain,
next to a Brenekke on the right..AS far as I can find only
sold so far as loaded rounds. They look great to reload with
if ever available..

3rd picture is from my Greener book, of double 8ga elephant guns.Ed