All firearms are stamped with the name of maker and serial number.
Private manufacturers.
Yes, provided you use the guns in a safe manner as intended by the manufacturers.
A variety of manufacturers made guns that were sold under the Western-Field label or brand.
Yes.
A gunsmith Actually, a gunsmith repairs guns. A "maker" is typically called a manufacturer. Some gunsmiths have manufacturers licenses, some do not.
I don't think you have to have a license to work on guns, but I'm not sure about that. To manufacture guns, you have to have a manufacturers license. Check with the BATF for more information.
Remington, Winchester, Sako to name a few
Many manufacturers offer free catalogs. Go to their web sites
Its called ebay. I'm pretty sure eBay won't allow guns. You can sell guns on gunbroker.com
No, mechanical guns are operated by a trigger (i.e. tippmanns, spyders). You can however buy a rapid firing crank from some paintball and firearms manufacturers.
Someone can buy cheap bb guns from a number of companies such as Amazon. Amazon has a large selection of bb guns from a number of manufacturers and also offers free shipping on orders that are $25 or greater.
See link provided below.