This is the Bolt Body only. Does not include firing pin, bolt knob, etc.

Markings include:

4036 d with Fraktur German Symbol with 3 barbs.

This most likely indicates it is from a Gewehr 98 or Karabiner 98k Infantry rifle used in WWI.

Features dual front locking rings, safety lug, hollowed-out gas relief hole, and Imperial/Military Markings. 

Rust and wear, used condition.