Purchased a used Glock 20 Gen2 with a WL prefix. Got some Underwood ammo and went to shoot it for the second time and it was not firing due to light light primer strikes 10% of the time. The primers barely had a dimple in them. Looked at the trigger bar and it is a 4256 with quite a bit of wear. This gun also has the black 4340 ejector. Looks like I have some work to do.