Got a Real World Weapons or Armour Question? Mk XII

[Brother Oni]

My 175 lb hunting crossbow will shoot a bolt all the way through a 1/2" plywood shield and it's not even nearly as powerful as say, a Mongol recurve.

I'd be careful about assuming that - a modern weapon is far more efficient than its historical counterpart.

A bit of digging indicates that most medieval crossbow prods only pull 4-6", while a modern one pulls 7-8" due to better quality steel and manufacturing tolerances.
Those couple of extra inches would allow for a significant increase in power, so assuming a linear increase in power out:draw distance, your 175lb crossbow could well equal a 350lb medieval one and hence match up against a decent draw weight Mongolian recurve.
This isn't allowing for any other design improvements that modern technology enables (release mechanism, modern string materials, etc).

Speaking of which, I wonder if a modern aluminium or a carbon fibre arrow would get the same sort of penetration as a traditional wood one? I'm thinking not since they're considerably lighter, but I don't have the equipment to test this out.
I'm also somewhat limited in the arrow heads I can obtain in this country due to laws on bow hunting (we're not allowed to so importing modern arrow heads might be a bit tricky).

Basically I think the sword continued to be really important for anybody above the status of cannon fodder until the primary weapon became a multi-use, high kill probablity / low failure rate weapon (i.e. rifle or carbine with cartridges) and the sidearm also became equally effective and reliable (revolver)

I've several depictions of American Civil War officers leading their men into combat with pistol and saber - is this not accurate, or were automatic revolvers not fully reliable/effective yet?