Challenger Arms Corp CO2 Pistol stamped M25 ???
Hopefully your AVA post will ring bells. More likely than here TBH.
your answer may never come but i would say this was done at the factory
the 2 match other 2's that are stamped on other guns and the white color is still in the stamping
a home owner would never do that, the white color, and also the stamping is smooth around the edge of the stamped numbers and letter
the why could be almost anything and another pistol so marked could not exist
but there is one picture here on the forum that appears to have a S stamped in the front breech, where they would sometimes stamp the caliber
it is low and a little crooked
again this could be one of a kind
yeah, I would really like to find out what the M25 means. I cleaned and resealed the insides of the pistol but did not touch the finish on outside. Left that original. The inside had a spring that was the same as you would find in a Fireball Apache (a close relative). so that made me think it is a early model but with no calibre stamp that leans toward a later model. The pistol is not "special" in any way that I can see so confuses me even more with the M25 stamp.
so could there be someone, somewhere that knows the answer that doesn't read air gun forum, i guess maybe
but that person could not be with us anymore also
i looked and this brand doesn't have there own forum
so don't be confused, you are one of the few that have a functioning pistol and if the the M25 bothers you keep the pistol laying on the right side
out of sight out of mind or just make something up, 25th of May works for me