Hi mate, to be totally honest you might get more help on umarexboysclub forum, there is a few strip down guides..
It's quite hard to tell by eye unless comparing the pawl next to a new one if it's worn or not as its slight when it is, but to me it sounds like a hammer and or valve issue..
Unfortunately though the umarex beretta is one if the few guns I've not stripped right down and had to fix, (apart from the pawl and arm like I say) so can't be of much more help, if your a member of umarexboysclub though put a post on there or if your not just type in the search umarex beretta strip down, if you can't do it or can't find it, I'll make a post on there for you then send you then links, when I hear more..
My umarex beretta is the 2004 models, and has seen thousands of rounds more then I can even remember at a guess 10000+ and I have only had to change the pawl, and arm once so them not being up to heavy use is just not true,, BUT i will say though the older versions are better quality then the newer Matt versions. But even our new version 1911 is nearly 4 years old and has been at least 4000+ pellets through it, as all things in life, Some things last and some things don't last as long or develop faults it's just the way..
Like I say mate jump on UBC
ATB, Marc.