Sidewinder Width

[sturtevant]

Looking at the specs, I'm noticing that the Sidewinder is 1-1/16" wide and most of the other NAA 22 mags (PUG, etc.) are 7/8" wide. What accounts for the extra 3/16"? Is it in the size of the grip? Doesn't seem like the cylinder diameter would be different between the two...

[VKSMINI]

sturtevant, it is the widest part of the grip