[Chickenthief]

Here is some wisdom i have scrounged somewhere on the interweb:

Ammo is too strong (usually the case).

Ammo is too weak (usually not the case).

O.A.L. of ammo is too short for proper feeding through the magazine (this is the number one Parabellum performance killer). This spec. is absolutely critical to proper function!!! IF THIS SPEC. IS MATERIALLY OFF, A LUGER CAN NOT BE EXPECTED TO FUNCTION PROPERLY!!! Original German Luger ammo was loaded out, for round nose, to 1.173 inches, (29.8mms), for conical flat point, to 1.142 inches, (29 mms). As you will see, if you measure them, modern commercial 9 mm ammo is loaded much, much too shortly to ever properly fuction in a Luger!

Bullet configuration is incorrect for the magazine interior or feeding ramp. Many modern Hollow Point bullets work perfectly, many just do not.

Magazine spring is too weak (usually not the case).

Magazine lips are bent or have been "modified" in the past.