This one hold also 60 grains of powder, with a huge caliber. In BP the caliber plays a more importanr role in energy than the amount of powder.
The Walker was “the most powerful” revolver for a short time, until de 1855’s...when the British and the austrians developed their large caliber, 50”, 54”, and 560” revolvers based on the Adams Beaumont design.
In reality, not even that is truth, as the british Baker transitional revolver, from 1852, in the huge 577 “ caliber, and several other transitional revolvers, were more powerful than the Walker. Some models were gas sealed.