Originally Posted by
tinydr
yep...
I don't really know anything about 520... elsewhere someone said it was standard 4130... make of that what you will.
Edit- mmm, might be double-butted 4130
All 4130 is double butted
afaik. The name (if I'm right) refers to the brand of tube---with its characteristic composition and butting profiles. Yes it's the same as 520 (I think). If someone can confirm all this or correct me, i would appreciate it.
Any butted tubing will be a nice improvement on gas pipe.