Only SP101 I have ever owned is a 4" .32 H&R with the windage adjustable only rear sight. Don't know how old it is, as I've never checked. It came (used) with a set of aftermarket grips that are sufficiently hand-filling to be pleasant to grip and shoot (I don't like sticky grips or those too short for all 4 fingers). Never had a problem with it.
During the 50+year course of owning handguns of various kinds, I've owned at least 9 Ruger revolvers (two .41 Mag Bisleys, two Security Sixes, a .32 H&R Single Six, a .32 H&R Bisley, a .22 Bisley, a .44 Special Bisley and the SP101. The only problem I ever had with any of them was the rear sight retaining pin on a .41 Bisley backing out when the pistol was fired, which was fixed by sliding it partway out, bending it slightly to put it under a bit of spring tension and reinserting it. Worked like a charm and never gave a lick of trouble after that.
Sorry to hear you're having problems.
