Start at the beginning –the Declaration of Independence. The Constitution lays out the structure of the government. The Bill of Rights embody the freedoms the allow us to post memes and comments here about guns in America.
Fully automatic rifles shoot 600– 900 rounds per minute. That’s 10 to 15 per second. 5.56 NATO rounds cost about $0.60US each. 500 rounds (bulk) 7.62 NATO about $660 US.
.50 cal rounds about $3.00 each. That works out to about minimum of $10 per second of pulling the trigger.
I couldn’t even tell you how much a modern cannon round cost. Muzzle loading, black powder, fuse lit cannons (pre-WWI) probably use about $5-10 of gunpowder, plus several dollars for a projectile.
A fully automatic rifle on the low end costs about $15,000 US. But, as you can see, the ammo expense can add up fast.
Replica versions of the hand crank Gatling gun sell for over $50,000 US
Most restored (collectible) military pieces are de-milled (inoperable). Here’s a company in Texas selling collectible artillery.
https://www.artillerymuseum.com/general-5-1