I recently received a XS-B12 break-barrel air rifle from Xisico. I am not too crazy about bbl, but somehow I like this one. Guess it was all
because of this picture that I came cross on internet. My idea about bbl is that it must look like a bbl, nothing else. I don't need a stock with an
extended fore-end to conceal the barrel joint. The style of B12 in the picture looks pretty good to me.
Ignore the fps figure in the photo, it must be a typo. As the information provided by Xisico, model B12 was intended for some European
countries (including Germany) where the max muzzle energy level of airguns are restricted. The manufacturer had to work very hard to keep the
power not to exceed 500 fps/.177 .A shorter and softer spring (of some kind of special steel wire) is used to accomblish this purpose.
The picture bellow is the B12 I received. The tone and finish of its stock is a little different than the one in the first picture. The stock is made of
very good Assian Walnut wood (same as B21) , and the finish is semi-glossy.
Overall, the quality of machining of on the metal parts is superb, just like its siblings B21, B18, B7 and B3. There are a few rough spots on the
bottom of the action.
Although not 100%, the design of B12 seems to have patterned aftern FWB-124, based on the schematic of 124 (attached at the end), also has
share a little bit similarity with HW-25. Like those classic European models, the barrel-lockup of B12 has a ball-bearing of 8mm dia. So, the
opening and closing the barrel feel pretty crisp. The barrel pivot screw has eight notches on its cap, and a small locking screw next to it. This
allows a fine adjustment for the clamping pressure.
The scope mounting grooves were cut all the way through the rear end. I wish there was a some kind of stop at the end. Well, the original 124
and HW25 are also like that. So, what can I say.
A comparison of mainsprings; from left to right: B12, B3, B12 and B21
The piston stroke of B12 is about 3.25". There is no reason that its power cannot be increase to 600 fps, or possibly over 700 fps, by
substituting its mainspring with a longer and stiffer one (such as the one for xs-b3) . Base on what I have seen, I like this B12.
BTW, B21 uses a leather piston seal, and its trigger is of fixed single-lever type, of course, just like 124.
Three things I need to do before I should start testing its accuracy;
1. polishing the piston rod,
2. replace the leather piston seal with a synthetic one, and
3. install a XS-B3 spring (available from xisico for only a few bucks).
Attachment: parts diagram of fwb-124
The following images of Weihrauch HW-25 parts diagram is linked from T.W. Chambers Co. site
http://www.chambersgunmakers.co.uk/Weihrauch%20plans/HW25%20plan.htm