Greetings all - I recently obtained an old handcannon which appears to have some similarities to that discussed in this thread, c. 1350:
https://www.vikingsword.com/vb/showthread.php?t=12151
Pictures are attached below. It is mounted in a reproduction tiller stock. The caliber is approximately 4.4-4.5 cm; overall length of the barrel is about 29.2 cm. The breech (“pulverkammer”) is about 1/3 of the overall length. Interestingly, the touchhole appears angled slightly from the breech at the surface towards the muzzle at the inside. This merits further examination. I will try to get an X-ray of the barrel, but as I have access only to a medical-grade machine I may not have sufficient power to reveal any detail.