Need any bullet experts out there to help me date these. How's this for a bag of interesting.........I was out in my own back yard with the metal detector (I have a 1 acre lot) and along the entire width of it I found about 6 of these in a straight line. As best as I can figure out so far, the are .50 Caliber, Armor Piercing bullets (I found one that was split open). I cleaned them up and they are in a copper jacket, 1/2 inch (12.7mm) by 1 1/4 inch (31.75mm). In the condition it is in now it weighs 1 1/2oz (46 grams and 684 grain) A little hard to see in the pictures but they have 8 grooves with a right hand twist. Back in the day when this area was undeveloped (high-desert), this must have been a training area for the military. An Army machine gun or possibly an aircraft strafing run from nearby Mountain Home AFB. Mountain Home AFB was a fighter and bomber training base back in the late 40's. If they are from the Army these could date back to WWI or WWII, the AFB was active toward the end of WWII. Any of you ammo/history fans out there, if you can help me out with information on these it would be appreciated.