Just slugged my Aussie AIA M10-A1 7.62x39. Bearing in mind that spec on this calibre is 301 lands -310 grooves, and that I haven't put anywhere near 1000 rds through the rifle, I was susprised to measure it as 3025 lands 313 grooves (nearest 0.0005"). I guess that explains their accuracy problems then, and adds to my suspicions that these barrels are chinese RPK-47 barrel stock (they are chromed and all...). Also, pushing the slug through revealed a slightly less than cylindrical bore... Anyone beat that for a new-ish barrel being larger than it should be?