The 15rd mags existed, might still have one in the mess
The MacMan book misses things, early things, great read but hardly a last word on what they were turning out early on. Many goofy variations up into the RPB era
Desantis rigs were offered in .45 and 9mm, thats why you had concealment mags...shoulder rigs and also normal belt holsters
have a beater PS holster somewhere. yeah normal on the belt, nobody better tell me you ran a full mag with those, that's just full idiot
old school Sionacs cans
Main issue was the end wipe assembly, blue neoprene...shot out pretty fast. Initial discharges were quiet as all Fuk. It's glorified WWII tech
in the late 70s some characters started doing Stirling style end caps, wipeless, selling free trade in SGN. Truth is a Sionacs unit is damn' effective. Ton of volume internally, the end cap just sucked dog balls due to the wipes so guys got into the lore they were not very effective. Truth was you blew out the wipes after a couple bursts thus evolved this myth of the inferior Sionacs can by the middle 90s.
Some SOTs seriously pushed all this
"repacking" cans, new wipeless endcaps, another issue was MACs had rather loose muzzle threads so wipeless endcaps were often larger than needed thus reducing their suppression, just liability issues.
Started with just doing rebuilds, evolved into new streamlined smaller units and what was done was beneath your typical over the counter "solvent trap" of today
old school...guys die cut replacement wipes. Well by the time the yuppie NFA Brigade moved in, well THATS UNLAWFUL, they will take my 928 Porsche Turbo or Audi LOL. By the late 90s the NFA community was already on knees, licking balls due mostly to urban professionals invading a new space
old school was quite a bit different and I for one lament all that