My son and I were just shooting the breeze about crossbows and their +'s and -'s. It came to how loud they are when you shoot them.
My boy is "wicked smart" and came up with this (think about it).
Compound bows use a minimum of 5gr of arrow weight per lb of bow draw weight, right? 350 gr arrow for 70#. You can make a compound bow much quieter normally by substationaly upping the arrow weight, say to 450 gr or so.
Well how much does a crossbow bolt (arrow) weigh? Using a 20" 2219 shaft, I think we guestimated at around 250 to 300 grains total. Call it 300 gr. Now shoot that out of a 200# (cross)bow. That comes out to 1.5 gr per lb if my math is right. No wonder they are loud! You are almost dry firing them every time you shoot one.
We got to wondering if you could quiet a 200# crossbow with a 1000 gr arrow (.5 gr per # draw weight), and still have acceptable arrow velocity.
We thought of solid fiber glass carp shooting arrows cut down, filling a 2219 or 2315 aluminum shaft with epoxy/lead shot mix or sand, or salt. There's a lot of ways to get an arrow to weigh a lot.
My son called on of his college buddys that is now managing a Gander Mountain store and talked this over with him. Last I heard, this guy was looking to see if he had a solid fiberglass carp shootinig arrow that he could cut down and set up to shoot out of one of his store's crossbows. More to come when I hear the results.
I'm a tinkerer and this almost makes me want to go out and buy a crossbow just to see if it can be done.