According to Steen and Paulson Brothers the metal carriages (steel or aluminum) cannot be used for live firing, I checked. They are designed for year round outdoor display only. Believe me, if they would work I would replace all of my carriages with them! But my guns must be able to handle full service loads as I compete with them at long range.
Yes, a properly made laminate can be stronger than a single piece of wood if there are flaws in the wood fiber (knots for example). A poorly made laminate is not. It takes good joints, alternating direction of the wood grain, quality adhesive, and constant even pressure. Simple clamps will not due, we are talking TONS of pressure. I would much rather have a properly laminated trail than one made from a single piece of lumber.
My MH bent the axle on the very first shot. Wheels & trail were on wood runners to ensure free recoil without digging into the ground. As I said, 12 lb. solid shot is too heavy for a MH, no matter what it is made out of, even if it does not break it will not be competitive. I am not guessing here, I know. I have been live firing full size Civil War field artillery pieces for 10 years now using everything from lead, zinc & iron, in the form of ball, bolt, shell, and canister, using reduced loads all the way up to full service loads in both smooth bore and rifled bores from 2" up to 5.82" in diameter...
Anthony