[SampleMan]

Rifles can be significantly suppressed, but not the typical rifle. Given F=MxVxV, the mass of the bullet must be signficantly increased to have the same or adequate effects.

A sub-sonic .50 cal 600 grain bullet (think .50-70) would be suitable for deer and more suppressed.

Of course, you’ll have to be a better shot, as hold over will be significant even at 300 yards.

[Tainan]

Using your example, wouldn't that .50-70 be a black powder rifle?
I don't think I've ever seen or heard of a suppressor being worked up for one of them.
That would be a real interesting exercise in engineering.