? Accuracy International Barrel Help

cp3head

Sergeant
Full Member
Minuteman
Jun 23, 2010
469
30
Pennsylvania
Hello Hide. I am looking for some help in identifying a barrel I picked up in a lot. It is clearly marked Gradous as well as the caliber. The specs are as follows:

2mm thread pitch, 27 mm diameter tenon by 38 mm long. It appears to be a Palma contour and has 5/8 x 24 threading at the end.

Is this an accuracy international barrel? If yes, are all accuracy international barrels the same (meaning aiax and at and older ai aeiii etc... )?

I would appreciate any assistance anyone can provide. Thank you all in advance.