Honestly man, I think it has more to do with the stainless vs blued steel barrel. I've got a couple 5.5s, and the blued, a convertible, just walks the stainless, as far as I know, a LR only gun, shooting most types of 22lr ammo. The blued gun was dad's, and we shot quite a few CCI Maxi Mags thru it, but i really only shoot long rifle out of it anymore. I gotta say, it is extremely accurate with the lr cylinder, I'm almost as good as the Standard MKII Target.
Just a thought, as I had heard the convertible barrels were supposedly bigger,etc., or the longer (6.5")barrels were not as accurate. I dunno.