I have one in a trap gun. Works very well. The above test sounds good, but it leaves out one important component--the human. Trap shooters have compared lead and mercury recoil supression a lot. The mercury wins. I can't assure that a mercury supressor would work on a rifle, but based on experience with a trap gun, I would wager it would. The down side would be the added weight, not too nice while carrying in the field. A trap gun never sees the field, so not a problem.
As to the snide remark about getting a gun you can handle, try shooting a 12 gauge 800 to 1000 times a day regularly and then see if you are so flipant with your "advice".