Alright, so I bought a 10mm pistol extended magazine (+4) and equipped it to my Weathered 10mm pistol. Now whenever I draw the weapon, there's this weird white filter that kind of covers everything and all it shows is my empty hand. Anyone know of a way to fix this? I really wish they'd give us a way to remove mods from weapons.

Yep. It's a known BUG. Never mod a preorder bonus weapon.

Someone has already made a mod to patch this until it is addressed by patch (if it ever is).

Weathered 10mm Mod Fix:
http://www.newvegasnexus.com/downloads/file.php?id=34794

NOTE: I know this works for the Laser Sight and Silencer, but IDK about the Ext. Magazine (I assume so from the file description). However, the creator was very responsive and quick to update when I pointed out a bug, so if it doesn't work as it, you could let them know in the Comments section at the nexus, and they may be able to add it.

HTH,
Flytrap

I bought the Ext. magazine today, and I con confirm this mod works with at least the Laser Sight+Ext. Magazine on a Weathered 10mm.