The SP101, while being a 5 shot "snubby", is a big and heavy gun. Loaded its about 2 lbs, and the frame itself is huge compared to other 5 shot revolvers.
The 2.25 or 3 inch SP101 is fantastic in the waistband, and vastly more shootable than a J-frame, but the SP101 is far from a pocket gun.
You could carry a Glock 19, in your pocket, as easily as the SP101...