Have slip ons installed on my single shot shotguns. Do a great job of reducing recoil. I will use them for this purpose on all single shots
Put one on an 11-87 and it shifted sometimes when I was taking multiple shots such as in 5 stand, but not terribly. Sort of felt strange at the very least. I wouldn't use slip ons for semi-auto.
Slip ons are dirt cheap and don't damage the gun to install, so you can't go wrong trying them.