Have you installed NVSE and NVSE stutter remover? I would recommend setting your max fps back to 60, since setting it to 59 will just introduce more stuttering, albeit slightly less noticeable than what you're probably experiencing.
Also, try removing any mods related to shooting those particular weapons. I've found that certain visual mods cause my game to stutter quite a bit, even though they aren't really resource hogs in any way. A lot of problems can be blamed on the buggy engine code.
I know some German (though I'll probably get stuck on technical terms), so I could help you out a bit, but there are probably people on this site more fluent auf Deutsch than I am. The site rules also state that posts are only to be made in another language if you provide a translation in the same post.