Everything depends on the length of the game, and what kind of game environment it is.
Figure out how long the game is going to be and in what sort of environment it is, then predict it from there. Generally people bring backpacks, rucksacks, and duffle backs and drop them in a semi-secured area somewhere in the rear (wherever you respawn). This is going to be your administration/sleeping/eating area. Invest in a good rucksack or large daybag. If you're on a budget I recommend an ALICE pack or CF 82 Pattern Rucksack. Both can be found for under 100$, sometimes under 50$. I recommend something with an external frame.
Lets say you have a 24 hour game in a woodland environment on a large field. Given the size of the field and the fact its woodland, you probably wont shoot as much as you did on a smaller, urban field (like PRZ in picton AKA Rhino) so you may not need as many batteries. It also depends on what kind of battery you've got.. are you using 800mah minis or 5000mah large? Given the size/weight of a battery, it is better to over-stock on these items. Bring a charger too and leave it in your car, just in case.
You will need a radio and extra batteries. Airsofters that dont use radios is a huge pet-peeve of mine. Milsim requires communication, it's a simple as that. With guys constantly rotating in and out, its not enough to have a squad radio man. Everybody should have one. How you organize radio nets is up to the commanders/leaders but its a necessity.
Water? This depends on the environment as well. Airsoft is a highly physical sport and you have alot of gear further dehydrating you. Obviously summer months will dehydrate you faster. Another case where it is smart to bring more than necessary. I would go with a rough approximation of 1L per 2 hours but you may want to adjust that. Check your pee. If you are properly hydrated you should be urinating often and the darker yellow it is, the more dehydrated you are. Drink even when you're not thirsty. Its not a bad idea to buy a jerry can and bring it with you. Leave it in whatever base/cp your team has (not likely to be overrun).
Food: Take something quick and calorie dense. Cans of chef boyardee with the pull tab are my favorite since you can eat them cold and quick. Pretty much anything will work though. Granola bars and such are good because you can eat them on the go. I wouldnt worry too much about food since you arent going to starve to death in 24 hours, and you dont want to carry 20lbs worth of rations thats just retarded. Just bring snacks and a few cans of the chef to keep your energy levels up and you'll be fine. You can bring a cooking stove if you want, but its not a necessity. I would suggest it in the winter/fall/spring months especially if its cold. A warm meal on a cold/wet day can make all the difference.
A roll of TP? Yes. You never know.
Sleeping gear: This is up to you. Its not a bad idea to bring a shelter half (tarp) or whatever, if nothing else than to keep your gear you leave behind out of the rain. Remember, all this crap is going to weigh you down. If you brought a gourmet meal, 40l of water, and your whole wardrobe... you are going to have a heavy rucksack (oh did I mention a rucksack is a necessity? youve got to carry all this shit somehow). There is no way you are fighting with your ruck, so you're gonna have to stash it somewhere. If you know you can't stay up and active for 24h (few airsofters can) then bring something to sleep in. I recommend short naps throughout the day. Play for 4h, take a 30 min nap. This should keep you rolling along. I personally recommend something like a ranger blanket or fleece blanket, but if you want a full sleeping bag its your call.
Other than that: socks. Wet socks suck. A nice fresh pair of dry socks and a warm meal can coax a smile out of even the most miserable troop. Also, glowsticks, duct tape, paracord, mechanics wire, and a good multitool. I shit you not these items can allow you to solve about 99% of problems on the battlefield. When I was a combat engineer I ALWAYS carried these items and I could MacGyver just about anything. Summer months? Bug juice. Lots of it. The more deet the better, if you can get pure deet shower in that shit. Dont get it on your goggles or it will melt the plastic. A good goretex jacket will go a long way if it rains too, but if you're strapped for cash any sort of rain jacket is a necessity. Make sure you pack enough warm kit. You'd be surprised how cool it can get at night, even in the summer. Add to that the fact you're perpetually wet either from rain or sweat and you will be quite chilly.
When it comes to milsim, rehearse the whole game in your head. Think about what youll need at what times and pack from there. For your first few games, ask people and bring what they tell you. Once you start to get some experience, you'll have a better idea of what you need and can pack accordingly. When your learning, its better to have it and not need it than to need it and not have it. I seem to be rambling but if you have any other questions let me know.
"Hokey religions and ancient weapons are no match for a good blaster at your side" - Han Solo
Commanding in Airsoft
Last edited by McKee; January 18th, 2012 at 10:22..