Original WWII German replacement 8cm Gr.W.34 mortar parts. Many parts are still partially coated in a red sealant to provide corrosion protection. The coating is original German also.
Not only would every mortar come with one of these, but there would also be one spare kept in the gunner's tool kit. This is the plug that threads into the bottom of the barrel and backs up the bolt. We used to offer a reproduction, but those are now sold out. Check that your barrel is threaded to accept one of these. On very early mortars they used a weird cap and spring clip rather than a threaded plug like this. Most mortars have a threaded one as the early non threaded version is extremely rare.
Parts are in great condition. Markings may vary; some parts have no markings. Only 6 available - no hope of ever finding more.