I’m not a fan but did at one time in my career carry a C-Mag 100 round drum when threat was high and violence of action was required to travel certain roads. 1 in the weapon an 4 spares in a bag on the floor.
Today Surfire makes a very good 60 round capacity magazine that packs easier than the hooter mags from C-Mags aka the Beta Mag !
Stay safe !
I have never owned any of the really high capacity pistol mags. I have several 20 round Mec-Gar mags for the Browning Hi-Power. Also several of their 15 round in addition to a few original Browning 13 rounders.
I do have one 30 round mag for the Browning. It has no markings at all but is reliable. I once showed it to one of the magazine vendors at a gun show. He looked it over and agreed that it was high quality. His best guess was Argentine military.
I also have several of the Argentine military 15 round ones. The spring is so strong in them that I leave them loaded hoping the spring eventually gets weaker. I have to use a mag loader to get the last few in.
The Mec-Gar seem to be among the best.