I'm considering acquiring a conversion cylinder for my Uberti Remington - Which drop-in system is best - the Kirst, or the R & D? there are a few differences - apparentlythe Kirst recoil plate does not rotate, and has only the one firing pin. What holds it in place, if it's a drop in (and I presume, drop-out as well) unit? The two pieces do not have to constantly rotate together (as they do in the R & D) so I presume there's less wear & tear between those two parts as well. Am I right? I'd like to hear from folks who have seen/owned either. Thanks, Griswold