I bought 1,000 rnds of 9x18 mak to use in my new smc-918. Took it to the range and about 1 in every 20 rounds would fail to feed and cause a real sticky jam. This bummed me out as I assumed it was gun, but as I drove home I thought about it and that didn't make sense. When I got home I broke down the pistol and tried to drop one of the cartriges that had jammed on me into the chamber. It wouldn't fit, would only go about half way into the chamber. So I opened up a box of fifty rounds and tried each one. Three of the cartridges wouldn't fit into the chamber, they were too fat. Opened another box and again 4 of the 50 wouldn't fit.
I don't reload but I know that cartridge case walls aren't uniformely thick. I know that they taper up to the lip. So what I speculate the problem is, is that the bullet is seated too far down into the brass causing it to bulge too much. Good news is that it's not my new toy that is the problem. Bad news is that I got about 800 rounds left of really crappy ammo.
Bottom line; silver bear ammo is junk. Avoid it.