I never cared for the super long mags either,in any gun. If you need that much capacity just modify an existing drum,ya,, more weight ,,but more capacity too and better ergonomics. If capacity is all you're looking for.
I modified a Romie military drum for my VZ and its awesome. With ,,way less length than a 40 rounder would be and more capacity. And lets be real about weight,,,,who cares,,when ya start getting shot at,,,you'll never notice the weight,,believe me. In Nam that 60 I used to hump,only seemed to weigh about 5 lbs when it was in use,,,,light as a feather,,till afterwards,,,
Adrenalin is a great thing!!!
Seems that if you find a 223 steel drum it should be pretty easy to tig on the feed lips from a sacrificial mag from the Mini sense there both steel. The VZ was a bitch in a way, had to rivet them on, original mags are aluminum and can't be welded to the steel drum body plus there was a million welds that had to be drilled out and tig-ed shut then re-drilled for rivets. It wasn't to bad, but time consuming. Works well if you're looking for capacity without excessive length. Those 40 round AK mags are something else too,,,hate them,,jam-tastics !!!!
Think I've heard that about the 40 round Mini ones too,,can't recall,,,,Pro mags I think I'd heard were the bad ones, not sure though. Someone else may know though???