When I began loading this mag, the first thing I noticed was the difficulty loading it. It didn't occur to me that such a magazine needs a very strong spring. It's not necessarily a con, if you are ready for it when you begin loading. Included is a lever you can pull (more of a slanted button that you press and slide) to release spring tension and insert the next shell. It requires both hands to load if you use the button, and that makes holding it awkward.
The biggest problem, though, came when I tried to insert it into the gun that it was specifically made for. The front lip fit fine, and I slid it into place. When I took my hand off, the mag sagged in the back: the back lip hadn't caught on the mag release. I tried hitting it in hard, but to no avail. The mag will not click into place.
Like I said before, this magazine was built with this specific shotgun in mind. It is advertised that these work with this gun. I have researched the problem online, and I am not the only one to have this happen to them. The suggestion is to file away part of the metal under the back lip of the magazine. However, when a customer has to physically modify the product to make it work the way it was advertised to work, the manufacturer has failed.
I cannot recommend other magazines, as this is my first magazine purchase for my Saiga 12; I only have my original 5 round mag and this Promag drum. I can still encourage you to do your research, though, and tell you not to buy this mag unless you are willing to do a little work to make this mag do what it's supposed to.