Ive pondered this project too, and frankly the cost of the rifle, plus the rechamber, and ONLY the possiblity of success, has kept me away. The cost of a new or used proven DG double is hefty, but the cost of the Pedersoli and conversion is really high if it doesnt work.

For the lower 48 I wouldnt hesitate to use the rifle just as it comes. 45-70 isnt a magnum but even the BP equiv. loadings offer more than enough for US non dangerous game.