I noticed that a groove seems to be developing on my VP9 mags. I don't know what is causing this. Is this normal? What do yours look like?

ETA: Based on some research I did online, it seems to be pretty common. It's just kind of unusual, because I don't recall a groove developing on Glock or M&P mags.


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That is normal.  My P30, USP45 generally have marks like that,

Yep, totally normal. You should see my XDM mags. It only takes a msg or two to do it as well.

Totally normal, and just so you are aware it's not the firearm itself, but the casings of the ammunition and the design of the follower.  Handgun casings are headspaced in the chamber off the cartridge lip/mouth.  It's hard to explain, and a pic is worth a thousand words so here are two pics, the first is a very detailed drawing of a .45acp cartridge in a chamber.  You can notice the cartridge has an extremely sharp mouth that is being used to actually determine the headspace.  The second picture is a higher level picture showing a general handgun cartridge and how headspace is measured.  Because of this you have a sharp lip on the case scraping against a plastic follower that is ramped to angle the cartridge for feeding.  As such the sharp metal lip scrapes the plastic follower smooth until all raised areas are removed (sort of like having your follower hand planed in wood working terms).  There is nothing wrong with this unless you are shooting with reloads that are of poor quality and are chewing your followers up.

Nothing to do with the gun.  Totally dependent on cartridge follower interaction.

My P30 and USP45 does this as well.  I noticed it around 3-400 rounds in.

Mine look the same.