Yeah, I would say you are close with that number. And, if it's a .22 it would be less.
It seems to me that most people start off with suppressing a .22, so I guess that is what I was thinking.
You know the rest. In the books you have read
How the British Regulars fired and fled,
How the farmers gave them ball for ball,
From behind each fence and farmyard wall,
Chasing the redcoats down the lane,
Then crossing the fields to emerge again
Under the trees at the turn of the road,
And only pausing to fire and load.