I have seen and shot only one .22LR that cycled rat shot. thisone was also meant to cycle .22LR, Long, and Shorts inter mixed. It also was not 100 percent reliable so I won't meantion it. It liked some ancient crimped shot loads I had best.
Them rifles ain't made any more or for a while. Got mine in 1967.
Oh, more crumudgeon points!
BTW Since the knee surgury I have been walking with a cane and wearing an honest to goodness hat rather than a ball cap. I believe those are crumudgeon point multipliers. Doc did warn its the sitting position rather than the kneel for me from now on.
-Bob Hollingsworth