The time to prepare your guns for survival is long before a major crisis hits. The replacement parts will be much easier to locate, be cheaper, better selection, and in most cases will be still legal to buy or have in your possession.
If you wait until just before or just after the crisis, any spare gun parts will either be unbelievably expensive or totally unavailable.
Gun Parts to Hoard to Keep Your Gun in Service for Life
To keep the firearms in good working condition a good firearms repair manual covering the firearms you own, several good quality cleaning kits, and a good quality shooter’s tool kit will be needed.
It is very important to know the estimated number of rounds the gun will fire before needing various types of servicing. From there, you can base purchases of spare parts and other times on the projected number of rounds you may wind up firing with each gun.
You should have at least enough kits on hand to cover all the ammo in your survival cache, and then double or triple based on what you may pick up after the crisis hits.