Question: Would it help on the real test if you train using a 35lb-40lb can?
Answer: It could help to do a can a little heavier than normal, perhaps 35 lbs, but training with the real thing will also be advantageous for you since the timing and rhythm will be exactly the same on the real test. A heavier can might be more appropriate for separate, general strength goals then test-specific training.
Question: I’m also using a 5.56mm can, instead of the one in the link, i’m assuming that doesn’t really matter much?
Answer: Correct–the size of the can is not going to be a significant factor. It will just be useful to get used to the awkward boxiness of the can. You can even just use a 30 or 35 lb dumbbell if that’s all you have.
The second component of the Combat Fitness Test is the Ammo Can Lift. To train for this unique exercise, you could use a 30-lb dumbbell gripped with both hands…or you could make your own can!
Normal 5.56mm (M-16 ammunition) ammo boxes are generally used, but if you can’t find any on ebay or Amazon, then something close like a .50 cal box would be fine. The weight is what needs to be precise: 30 lbs.
Just fill it with sand or earth until it weighs net 30 pounds. Not rocket science here.
Grit tape makes for an excellent grip-enhancer. After running or in the heat, your hands will get very sweaty and the ammo can could easily slip and drop to the ground, or worse, hit you in the face. Be careful if you don’t use the tape!
Most units in the Marine Corps, and also at OCS, you will have boxes prepared with grit tape.