Thats right, the Mm410 and Mm410B are completely different.

So the question is if the first series .22 with this small bolt shown in my pic ever had the feature that you see in the pic. I have had quite a lot of first series, but never have seen on with this bolt feature, other thing is that the Mm410 is very rare and for me this is the first example that i have in hands. So i dont know if this bolt feature is found on other first series .22 s.....