what is the best barrel for automag classic?

[soundmixer14]

which is the best?

[Dayspring]

One that best matches the paint that you regularly use. (Yes, paint comes in different sizes.)

That's why people get the barrel kits- Scepter, Freak, Pipe, Longbow etc. That way they can tailor their barrel to the paint they shoot.

[soundmixer14]

what barrel thread does the automag classic use?

[Dayspring]

AGD Twist Lock

Only AGD guns that take Cocker barrels are SFL, Xmag and any one equipped with the ULE body. Anything else is Twist lock.

There is the Doc Nickel adapter. It takes the Twist lock "threads" and makes it into cocker threads. Check the dealer forum for them.