Nice 1917. Above average.

A letter "K" stamped on the underside of the bolt handle would identify this as a Kingsbury bolt made in WW 2.

If a letter "K" were stamped on the top side of the bolt handle, it would be an Eddystone bolt made during WW 1.

Eddystone stamped the top side of their bolts with letters A through Z for some reason.