Larry;
You just don't much get Mathamatics do you. You "DID NOT" pay 6.00 per 25 for the hulls, you paid it for loaded shells. You are thus figuring in the price of primer, wads & shot for the first firing, but not for the remaining loads. This is thus "NOT" the hull cost per shot, Period, nor is it the cost per shot as the components were not added for the others.
If you bought a new automobile & paid $30,000 dollars for it & kept it long enough that you put on two more sets of tires @ $450.00 each set you would have a total of $30,900. You would not of course say the coet for the tires was $10,300 per set.
Likewise the Components of that original box of shells likely cost more than did the hulls themselves, so you cannot say the hull cost was $0.06 per shot.
To be a really valid comparsion one simply needs to figure the total cost to load for some given unit, whether per shell, per box, per 100 or whatever unit as long as its consistent.
Final verdict would I feel sure be, the 12ga is cheaper to shoot, but it just might also show that one can save more reloading the 16 than the 12. Reason being that even though it is slightly higher to load the 16's there is likely not as much difference as in buying the new factory loads.
