Does anyone know what the muzzle velocity differences between a 16" barreled .22WMR and a 22" inch is?
Off the top of my head, no...
But I can tell you with a standard 40gr WMR load, you hit peak velocity around 19.5" of barrel length.
Some of the hyper velocity will pick up a bit more for another ~2inches.
I would suspect the velocity difference would be less than 100fps with most standard 22WMR loads given those barrel lengths.
Noise, will likely be quite a bit higher in the 16" however.