This is the idea of staff mate
1) basic tuts about o2
2) advanced tuts about making addons and others OP software (ex :Anim for OP and )
...
Added : "Ammo crate" tut AND some blueprints :
US : Maxson "12.7mm * 4" (AKA "0.50 * 4")
IT : Autocarro SPA 9000 C con cannone da 105/35
UK : Vickers MK I 303
AT