Ian,yes that bullet is old,and it has been fired.The shallow lengthwise grooves were engraved by the rifling in the bore of the barrel.There are likely four or six grooves around the bullet.The smaller groove around the bullet is probably the crimping groove where the mouth of the shell case was crimped into it to provide a secure grip on the bullet before firing.The larger groove was filled with a lubricant (like grease or wax) to soften the powder fouling.I believe your bullet was fired from a cartridge loaded with black powder,so over about 100 years old.It does not look to me to be from one of the standard military U.S. cartridges.It might be from any of a large number of sporting or civilian cartridges of the day.If you can measure the diameter of the bullet with a caliper or micrometer or ruler to the nearest 1/32",and weigh the bullet in grains,the I or someone else might be able to tell you what cartridge and maybe even what make and model rifle that bullet was fired from.I'll try to remember to watch for your post in case you can provide that info.
