I purchased this when they first debuted coupled with a G&G GR-16 Pro. Since then I've put 40,000+ rounds through it so it's time for a review. Mine was perfect straight out of the packaging. I didn't find any defects whatsoever. I can't compare it to the 6.035mm tightbore that the GR-16 came with as I haven't fired a round through it. There is a very noticeable difference between the ASGI 6.03mm and this 6.01mm. The gun becomes very precise with a 6.01mm tightbore. For the price and the availability I'm giving it a 5/5. EDGI, DBC, and Madbull barrels are superior...but these don't trail by much. They're definitely worth the money and installation. Be sure to clean these barrels often. I recommend bringing a cleaning rod + cloths with you to games.
Nice, Smooth Finish (Nickel Coated)
Hop-Up Cut was precise and free of defects
Increases FPS (10-20fps)
Increases Range (20-50ft)
Increases Accuracy (1in groups @ 100ft)
Not the exact length of M4 length barrels (It's not a big deal but others could have problems)
Rating: [5 of 5 Stars!]