Just my 2 cents here.

Generally, the weight of English guns are very well matched to their power level, but only generally! That is, in the absence of other markings, a 13lb gun is probably build for heavier charges that a 10lb version in the same caliber. I don’t know how well this holds for trade guns where one frame was used for many calibers.

Notable exceptions are some guns from the early days of nitro powders such as 12lb 450/400s (overkill!) and BP guns that were reproved for cordite, some of which were much too light.

Bob