It looks like a British (or Indian) socket bayonet for a Brown Bess musket. The Brown Bess was produced for 200 years. If you post accurate dimensions (OAL, socket length, & socket ID), plus a couple of additional pics (showing the whole socket/mounting slot and an overall shot, we can probably narrow it down to a reasonable range.
If you want boardmembers to help you, you need to do them the courtesy of providing some information to go on. If you won't take the time, why should we? No offense intended. Just a point of forum ettiquette.