The last inch of the barrel of my 9c is larger than the rest. The difference is only 0.17mm, but it is noticeable. I measured using a micrometer and the muzzle end is 14.34mm the rest is 14.17mm. Is this normal?
Yes it is. The larger diameter is to permit a better "fit up" with the slide when it is all the way forward. A close fit here increases the accuracy potential of the pistol.
The reduced diameter behind this area is for clearance as the slide cycles. The barrel tilts downward as the slide goes to the rear, the larger clearance permits the barrel to move without binding.
9c barrel size difference?
Linear Mode
