Well I have to admit that it does seem to be a bit more difficult to take down enemy fighters, even tho you are getting what seems to be alot of hits on them, and it seems to take very few hit's on yourself to be in trouble.
Hmmm im wondering, I havent seen any options to adjust your gun convergence in CFS3 so far unless Im not looking in the right place.
If this could be adjusted( and it can on the real planes) that would help, as it would let one get the distance of convergance out further, or in closer depending on your expected combat situation, or for just your personal shooting/attack style.
The convergance to me seems a bit to close in for my comfort.

You can adjust the convergence by opening your xdp file (in notebook) located in youe plane's folder. You will see the guns near the top, just scroll over to the convergence, almost always 300 and change it to what ever you want. Click file, then save. This will disqualify the plane from MP, though.
The sim is exactly as you guys are saying.
When I built the BoB JG-2 missions, I had the hardest time with the RAF fighters. Could hit them 100 times and more. But, scratch the paint on my 109 and she couldn't fly anymore. I am finishing BoB bomber and BoB RAF fighter ( same missions, just switching to new cockpit) with the soon to be released 1% Spitfire Mk1A (What a super plane and great cockpit) Well I don't know why those German bums had no guts when they flew with me, but they are terrors now that I'm in the RAF. God save the queen, they are kicking my ass. And, the Spit that was as tough as a King Tiger is now made of fine china.
That is just how it is.
When I first started BoB JG-2 fighter testing, I thought I would never master the 109 over the Spit. But, I learned its strong points and eventually tamed the super Spit. It really made me a better sim pilot to be at a disadvantage. Download that Mig-15-931 and get the two missions at SOH and you will be glad to get back to whatever crate with a prop
Wulfmann