Re: Unusual Single shot pistol B U Crown proofs
The markings are German proofs. Crown of U means inspected. Crown over G means rifled. Crown over B means Mauser powder M-71.
I suspect the numbers on the side are the load. If you figure that to be Grams, and not Grains, 0.2 grams of M-71 powder comes out to 3.1 grains, while a 1.8 gram bullet comes out to 28 grains, which is the same weight as a 22 short bullet.
Meddle not in the affairs of dragons, for thou art crunchy, and taste good with catsup - George of Lod, Year of Our Lord 297
I always take precautions.
Beware the Evil Bullet Fairies.