Hi Bill, Have fun with your drum! The reason it is locked open from G.T. Specialties upon delivery, is that when the swing arm is unlocked and rotated to "weak?" the follower spring is fully tensioned and when shipped, tends to pop out the top causing the more faint of heart to return the drums untried!!! …..
... It is ready to load and ammo recommendations are primarily WW 115 grain ball, maybe even better is Federal 124 grain std. ball? (the heaver bullet has a bit better energy pulse when cycling it the Luger?)
Most of all be careful! Any jams or malfunctions, clear the weapon first, address the issue later... Best to you Bill, til...lat'r...GT....
