I have used them and have found some to fit me well, and others not so well. For a rimfire, I think they work well. I used a 870 with one for turkey hunting one year and the recoil from shooting heavy turkey loads from an awkward position felt like it broke my thumb. That said, I found the same thing happened once when shooting my 500 Mossy in the same scenario with my thumb on top the stock(by the safety), only it was my nose that felt broke. Safety position on the rifle might impact my choice too. Safety on the trigger guard, or 3 way similar to on Ruger rifles, accessed with one's finger, not a problem. Safety on top of stock/back of receiver, might be difficult to access with your thumb in the hole.