707 ultra 9 mm barrel question

Hi guys, today i completely stripped my 707 ultra, mostly just out of curiosity.

Besides noticing that koreans probably never heard of quality control or making use of decent quality materials, i found out that the pellet probe O rings were completely trashed cause of sloppy fit and out of whack tolerances between the parts… But well, that’s a relatively easy fix. (gotta shim the pellet probe, polish some parts and put a few new o rings on.)

More interesting was the bore condition of the barrel. I’ve never seen such rough rifling, when slugging a pellet though the bore it feels as if the bore is been coated with sand paper… a far cry from the smooth bore i have in my airforce rifle.

Accuracy is still fine to at least 25 yards, but haven’t done any proper long range testing yet.

My question: is this a common thing with the career barrels & will the bore smoothen after a few hundred rounds? (gun is basically brand new)

i know, i know, if it aint broke don’t fix it, but in case accuracy isn’t what i think it should be @long range; can i smoothen the bore with stuff like jb bore scrub or a similar product? looks like the rifling is just rammed in the barrel!

Any input? cheers, vincent