10ga is short for "10 gauge", a unit of measurement for the thickness of the steel.
10 gauge steel is equal to 0.1345 inches, or 3.4163 millimeters. The thickness is somewhat different for different types of metal (galvanized steel, aluminum, etc.)
ADDITION
As stated earlier, it depends on the steel.
10 ga. clean steel is .1345 inches. Galvanized steel is .1382 inches.
10 ga. aluminum is standard .1345 inches.
100-500 USD.
Yes, if it is a 10 gauge shotgun.
20ga, 12ga, 10ga and if you were poor a 410.
About 750.00 if its in very good condition .
100-675 usd
That 10ga with a 30 inch barrel was made in 1892.
Not more than 100-125 USD.
Call Ithaca. If they don't, they might know who does.
There is no restriction on different size wires being spliced in the same junction box. If your question involves splicing 8ga. to 10ga, this also is not a problem so long as the circuit allows for 10ga wire.
Probably about the same, but 10ga is huge for ear piercing.
If you go to the browning home page,they may be able to answer your question.
Can be as high as a few thousand dollars. Value will depend heavily on exact model and condition.