re: Hypothetically? Is there a way to muffle or silence a 22 rifle?

1st. For noise reduction you will need subsonic rounds to avoid the crack from the report.

2nd. MOST .22 cans are conical baffles. Some are stacked baffles but I think the Conical shaped baffles end to end (think Funnels with little holes drilled in them) works better.

3rd. First round is always going to "Pop" louder than the rest. Gasses heating up inside the can cause the can to get quieter. (I Don't remember why, but it does)
3rd- a) The first round pop can be reduced by Lithium grease (messy) and more commonly spit. This leads to the terms Wet and Dry Suppressors.
Older cans needed a lubricant of sorts to be optimized.

I think there might be one or two other guys that own/make them from what I can gather. I saw mine being made and know a little bit about the inner workings. I have seen and shot a bunch of suppressed guns. Different brands work better than others, integral is MUCH quieter on a .22 than a twist on can. I have one that you could shoot in your front yard and your neighbor likely wouldn't hear it.