Midway up the chamber, those 2 parallel silver lines. If you run a toothpick over them you can just barely feel them.

I have 165 problem-free rounds through the gun. They aren't scratching or marring the brass, it's staying perfectly slick.

Are they anything to worry about? My understanding is that you can't polish a chrome chamber, so should I just roll with it?

I have a Px4, I have 2 slides for it ( long story ), and 3 Barrels. 2 Standard length and 1 Extended. This piqued my interest so I took a look and none of them have that type of chatter mark in them.

How's your brass look? If it looks normal I would say go ahead and shoot it, If not contact beretta and see what they have to say.

Zach A.

Brass looks perfectly fine. I called Beretta but their gunsmith was busy so the rep said he'd email me after he shows the gunsmith the pics I sent him. I'll update this once I get a response.

Those are chatter marks. They happened, then the chrome was applied over it. It's not really something you can fix. If you cut more to make it smoother, you'll loose the chrome there (which creates flaking later) plus that would make it bigger. It's already oversize where it chattered. A 9mm chamber reamer won't cut any larger than spec dimension, so to cut at all you'd be using the wrong tool. Bad juju all around.



As far as what it causes negatively... nothing until the chamber/gun gets extremely dirty. Then it will cause a decrease in reliability, due to increased fiction/resistance to extracting. You'll encounter this soonest with weaker-loaded ammo, assuming an equal level of dirtyness.



If I were you, I'd gripe to Beretta explaining this is a big problem for you, in the hope they replace your barrel for free. They'll likely try to downplay it, and that's after you get them to acknowledge it exists. The pics will prove that fine. Be firm, but not a total d. If they don't replace, it may not really be a big problem. You're talking field conditions of killing zombies for days before the reliability bug bites. Now I understand that may apply...

If so, raid or trade for some +P, keep calm, and fire on!

Consider it like a fluted chamber delayed blowback... The case gripping the chamber is the only reason certain firearm designs work in the first place (FN 5.7 is the first to come to mind) It'll just make the gun run smoother with +P ammo...

:-)