This is a deep dive ! , my deepest was 148 feet. Are you going to use surface supplied air or a tri-mix ? Going into a type 7 with 2 tanks is a tight fit, anymore than that you are going to have some job getting into the boat and moving about without stirring up a cloud of silt. I use steel 94's that is 104 cubic feet with the 10 % overfill because they are smaller than an Aluminium 80 tank ( but are very heavy ! ) . When it comes to unexploaded ammo I must admit I never worry about it, When I dive the U-853 I worry more about seeing sharks ! ( only once in 20 years of diving did I see one and it was a 5 foot mako swimming near the wreck of the BLACK POINT which the U-853 had sunk ) . I have seen alot of rotting clips of 20mm ammo ,never any 37mm and a few 88mm rounds. Since the Germans were very short of raw materials such as copper, brass etc most gun cartridges were made from steel and coated with a brown lacquer. Since most of the ammo is made this way it will be mostly rusted through and pose little or no danger. Torpedoes that are outside the boat in storeage containers and the ones inside the boat but not loaded into the torpedo tubes also pose little danger as the do not have the exploader/detonator installed in the warhead, this was done for safety reasons. Screwed into this opening was a plug but over the years this must rot away as I have never seen one and the torpedo was open to the sea. Since this is still an explosive device I would not strike it hard, as long as you leave them alone you will have no problems . Torpedoes still in the tubes is another matter ! THEY ARE LIVE ! once the exploader is installed these tinfish can stay watertight for along time. There are four prongs or whiskers on the nose of the torpedo ,do not hit or bend them, this is what sets off the torpedo to expload. It should not expload as the torpedo must travel at least @ 400 meters before the exploader is armed. This is a true story, in 1981 US navy divers were diving on the U-352 to disarm the torpedoes ,but one diver hit the prong of the exploader by accident and CLICK !!!!!!!!!!!!!!!!! the pistol went off but since the torpedo did not travel the distance needed to be armed the striker was not engaged to hit the detonator so it did not go off.I bet that dry suit had some load in it after that slip up !! As A GOOD RULE LEAVE ANYTHING ALONE THAT WAS MADE TO GO BANG and you will be fine. Your biggest hazzard will be the fine silt built up inside the boat. Know all routes into and out of the boat and use a penetration line with glow sticks every few feet, it takes very little to stir a blinding silt cloud.