Crustyclad wrote:
> Does any one know what cal[iber]
Based on comparing your bullet's diameter with the penny in the photo, I estimate it's a .38-caliber pistol bullet.
To get a close estimate of a bullet's caliber/diameter when you don't have Calipers for precise measurement:
A modern US penny's diameter is .750-inch. So, a .38 bullet is almost exactly half of the diameter of a penny. A .32 pistol bullet's diamter would be noticeably less than half a penny's diameter.
> and about how old this bullet is?
The attached photo (below) shows a pistol bullet which has what is called a "reeded" groove. To understand the term... larger-denomination US coins have a "reeded" edge. No civil war bullets had a reeded groove. Bullets with a reeded groove began to become plentiful in the 1880s. That's about the oldest your bullet could possibly be.
All of that being said... I agree with Duggap... your pistol bullet's short flat nose indicates it is a late-20th-century "wadcutter" bullet ...made for target-shooting. A wadcutter bullet's flat top cuts a nice clean easily-visible hole in the target.