Many DA revolvers can lock up in rapid fire if you don't fully release the trigger.
That wasn't the case with the SP101. I'm well aware that DA revolvers need the trigger released completely before resetting for the next DA shot.
On the SP101, something was binding internally during rapid DA firing. Ironically, cocking the hammer for a SA shot would somehow "put everything back to rights," and the gun would function normally for a couple of DA shots, then lock up again.
I could never figure it out, and, apparently, neither could Ruger, hence, it went bye-bye.
I will say that this is the ONLY DA revolver which gave me that problem; I have never had a Colt, Smith or any foreign DA lock up like that.