@CPS and on my question: The stats of the waepons changes with level. That means on level 30 for example you have a 7 % bonus on accuracy or relaod time or whatever. You can find such things on your stats page in the main menu. If I get this right, these boni combines with the boni originating from your class rank. The arisaka indeed gives you now additional bonus on the second level, as it already comes with a bayonett. But it might gives you more ammunition, I have to check that. While the americans indeed get a bayonett on your rifle, once you have reached level 25 with the garand or the springfield.
So far I really like these waepons rank system. You not only get used to the waepons by yourself, but also stats wise. In the first games it always felt like you couldn't hit a barn door, while know you can perform longer and longest range shots with the rifles. This feels really natural.