soberups
Pees in the brown Koolaid
An SKS with a 10 round fixed magazine loads from the top using stripper clips, not from the bottom.SKS's come with a fixed 10 round clip. You load it from the bottom. Adding an aftermarket 20-30 magazine causes it to jam. They're my least favorite rifle. But, I bought them years ago for $98, new in the box still covered is cosmoline, now my girls are worth $300 a piece. The SKS is a bad choice of rifle when talking about high capacity magazines.
You are correct that the aftermarket "duckbill" magazines are junk. Some SKS's (Norinco M and D models) were designed from the factory to use detachable AK-47 magazines.
The shooter in Dallas didnt use am SKS. He used a Saiga in 5.45 mm which is basically the Russian version of a .223 AR-15.