speeking from experience, with good and bad results, PVC is great, clean and use the primer! a little RTV around the mating surfaces, just incase some uncleaned plastic debris, makes a small void, you don't catch. ammo in vac bags, Buy one for the wife, and use the hell out of it! Better than the bowling ball gift! machines parts, store in transmission fluid. What you want is about four tubes that are not to long, and less than 6 inchs wide, all your wood, and other stuff that collects moisture in one, ammo in one, steel/metal in one, the last food tabs,polylong johns(they vac down small) survival kit etc... Use a post hole digger to install, you disturb a lot less top soil. you can tie lanyards or safety wire to pull things out, with out removing tubes. Tubes can be reused, with little effort, and camoed. the bottom of the hole should have a couple of inchs of gravel to keep the tube from sitting in water. These work really well under rocks and other natural or even town stuff, (stepping stones) etc...
No Slack, Light Attack, When your hot, your hot, when your not, your dead!