I've done a bit of shooting with a Nikon Monarch 2x20 EER scope on my 620. BTW, this particular model features 1.75X magnification so it's not a true 2X scope like the newer Nikon Encore.

IMO a 2X scope is a nearly ideal scope for 50 yards if your intent is to achieve Hunting level accuracy. There is ample magnification to shoot groups around 3 inches at that distance and they are relatively compact and light in weight. The only downside is that if you are shooting for pure precision, it's a bit lacking in magnification. An NRA 25 yard slow fire target looks pretty darned small at 50 yards in the reticle and you REALLY have to concentrate on getting the sighting dead perfect.

To sum it up, 2X makes shooting a 3 inch group at 50 yards duck soup if your load and gun are up to it. However, if you want to try for groups of an inch or less you'll probably want a bit more magnification.

PS; I can give a hearty thumbs up for Nikon's handgun scopes, the clarity is nothing short of perfect and mine has held zero perfectly. However, I'll also warn you that you need to snug the mounts down good and tight, on my first outing I shot the rear mount loose after 46 or 47 rounds downrange.