Hello, I'm brand new to metal detecting and found this in my back yard. I live on 13 acres across the river from downtown Chattanooga and old maps show my land being a "Site of old fortification" This item weighs .285 ounces and appears to be lead. Is it a bullet from the civil war?
Ticndig is definitely correct, Keith... it is a finial.
In case you'd like to hear a more-specific ID:
Being found "at the site of an old fortification" (old meaning in this case pre-20th-Century), and being only 1/2-inch long by 3/8th-inch wide, it is most likely a Cap Box finial. That "box" was a small leather pouch which held a soldier's copper percussion-caps, for priming his blackpowder musket or pistol.
When manufactured, your finial had a short round stud projecting out from its base. The stud went through a small hole in the leather cap-box's upper front side, and a rivet-disc was hammered onto the stud to tightly secure it to the box.
Ticndig's photo shows several excavated civil war era cap-box and cartridge-box finials whose riveted base is still intact. A few of those still have a little of the box's leather body preserved between the finial's flat base and the rivet-disc.
The cap-box was worn on the soldier's belt.
I should mention... most of the cap-box and cartridge-box finials we dig are made of brass. The lead (actually, lead-solder or pewter) ones are "said to be" Confederate-made -- but we know some pewter finials were manufactured before the civil war. So, there's no way to know for certain. For example, civilian game-hunters would also use a cap-box... and might have brought it with him when he enlisted into the army.
Almost forgot to mention:
I see your posts in this discussion are your very first posts here at TreasureNet. So, welcome to T-Net's "What Is It?" forum... the very best place on the internet to get unknown objects CORRECTLY identified. I hope you will continue to read this forum -- you can learn a LOT of valuable information for free here. I certainly have. (I hang around to give something back... and, I'm still learning.)
I don't think it is a stud for holding the flap of a holster or cap box closed. There doesn't seem to be a way to fasten it to the body of the holster or box, and it seems to be a little too large. Look up collar button bullet on Google and see if you think that is it.
BAW, your theory is interesting, but I'm standing firm on my ID of the object as a Cap-Box finial. This one is made of either pewter or lead-solder (a.k.a. "Hardened-lead alloy"), which tends to be brittle, unlike a brass finial. In my opinion, the rivet-stud on this finial's base broke off. If you look closely at a couple of the finials in Ticndig's group-photo, you'll see that finial #5 in the 2nd row and finial #8 in the 5th row (both of which are pewter or lead-solder) appear to have a broken-off rivet-stud. Also, if you look closely at Keith's photo of his find, its base is not flat (like a "collar-button bullet" base should be), but instead has an irregularly-shaped projection at its center. I think that short projection is the remnant of the broken-off rivet-stud.