Re: Mercury Recoil Reducer/Suppressor
I think they are effective. I think the same mass, added as an inert weight, is nearly as effective and probably is a lot more affordable.
The value of any recoil reduction is in the fatigue reduction they provide for repetitive practice. There are a lot of ways to achieve this.
The mercury reducer is a real option, and if I were less concerned about expenses, I might consider one. My most common tactic is to fill stock voids with buckshot. Another one which does not add weight directly to the rifle itself is interposing mass, similar in principle to a Lead Sled. This can be achieved as simply as stacking a sand or shot bag between shoulder and butt plate.
The position one shoots from will also influence recoil tolerance. The more upright, generally the better the tolerance.
Context has a bearing too. Shooting at randomly encountered game in the field generally makes recoil less noticeable than a sustained sequence of fire at the bench. Be advised that shooting supported free recoil from a bench will generate a different, usually higher, POI than shooting from an unsupported field position.
IMHO the best recoil reduction comes from doing everything but sight-ins, primary application, and load confirmation with the rimfire instead of the primary firearm. IMHO, it reduces wasted ammo, bore life, and shooter stamina. A fatigued shooter does not practice as efficiently or as effectively as on a fresh one. Where practice is impaired, so must be any benefit one expects to gain from that practice.
Greg