I have a few questions I'm looking to get some help with. 1) I own an AR15 and was trying to figure out what parts I should keep spares of that will be a must have for keeping it running properly in a shtf scenario. 2) Same as the first question but for my HK USP 40. 3) Lastly wondering what tools I should have incase of work needing to be done on either of these firearms I've already asked about. Any Info/Opinions would be greatly appreciated.