Things You'll Need
Instructions
Searching
Select a likely site --- perhaps a popular hunting location or known battleground. Obtain the land owner's permission to go metal detecting. Carry spare detector batteries and plastic bags to hold finds.
Turn on the metal detector. Walk slowly across the site with the detector head close to the ground. Pass back and forth over the area so that nothing is missed.
Listen for the beep indicating a find. Dig carefully with the trowel --- finds are small and sometimes fragile.
Responsible Collecting
Fill in any holes you dig and replace the sod. Avoid damaging any archaeological features, e.g. earthworks on battlefields.
Log finds in your notebook --- archaeologists are gaining respect for detectorists and will appreciate your record keeping if you make a significant find. Maintaining the cooperation of these experts relies on responsible metal detecting practices. Keeping careful notes will also help you with identification, dating and in pinpointing sites worth a return visit.
Respect any other metal artifacts found incidental to your hunt for shotgun shells -- they may be of interest to collectors of other items, to the landowner or even to museums. Dispose of trash finds responsibly -- do not leave sharp or rusty metal littering the site.
Identification )
Wipe dirt from outside of shell. Do not wash out the inside immediately. Any residual content can help identification --- black powder is a sign of an early shell.
Check the base of the shell case for brand identification -- Winchester, Alcan, Browning are some examples. Look for a number on the base, identifying the gauge. Some early shells came in gauges that later went out of production.
Consult the headstamp identification list at http://members.shaw.ca/cartridge-corner/shotgun.htm. Use this to date your finds.
Self-education and Selection
Join a metal detectorist or ammunition collectors' club -- local or online -- to ask questions of the experts. Take finds to your local museum for a curator's opinion. Join the International Ammunition Associationand attend its collectors' shows. Attend collecting group meetings and auctions.
Read extensively about old shotgun casings. Use the IAA Journal archive; buy books at collectors meets or on-line--several are out of print, but they are available --- see the resource list.
Choose a production date after which cartridges are insufficiently old to interest you; indiscriminate collecting leads to clutter. Specialize in a particular era or brand. Be selective in the finds you save. Swapping finds with other collectors can help streamline your collection. Collecting by country of origin or purpose (police, military or sport) are other options, especially if you intend purchasing your collection.