First Mr. M, Congrats on your "nice pair!" 
I've been a fan of the 520 for a long time. Most of my 520 info has been from Coppertales who frequents this Forum & he's been my go-to info expert. Not to 'dis' anyone else here, just that he's very knowledgeable. Hopefully if you don't get your diagram, he can help you.
I personally prefer my 520 models as my tea. One lump, not two. They're great & interesting guns.
Best!
John
I've been a fan of the 520 for a long time. Most of my 520 info has been from Coppertales who frequents this Forum & he's been my go-to info expert. Not to 'dis' anyone else here, just that he's very knowledgeable. Hopefully if you don't get your diagram, he can help you. I personally prefer my 520 models as my tea. One lump, not two.
They're great & interesting guns. Best!
John
