I guess I'll jump in here, I have two Saiga-12s. One is running the other is in pieces, I have the bolt and carrier off getting spruced up along with a modified trigger group. I plan to shorten the 18" barrel and permanently attach a Molot GK-01 brake, or I should say I'm going to have that done by a smith with the right license.
I've never been big on shotguns in the past but I love these boys.
Anyone ever want to shoot one let me know and we can meet up at Quickshot. As a member I can bring guests no charge. Just bring some slugs.
Oh, and about the drums, or at least the MD drums, I've been lucky that all the ones I have fit with no work. But it's better to have to remove some material for a tight fit than have them loose from the git go. Supposedly, it's almost the stuff of legend, that Mike Davidson is working on a double stack stick type mag but no one knows when they'll be available. I usually run AGP 10 rounders and they work well. At $30 each they're the best deal IMO. A 12 round mag is just too long for me. I also have a ProMag 12 round drum.