I put this in my ICS M4 and I'm absolutely amazed by it. With the stock 6.05 tightbore I got around 200 ft with 10 - 12" groupings with .2's. With this install it was increased by 20 ft or so and groupings were reduced to around 5" - 8". I've heard many people asking whether to grease it... No you never "grease" and inner barrel.. ever.
I've also heard people say that their .2 bb's fly up with their hop up off. You may have put the bucking on incorrectly or have a faulty hopup etc..
I use .2's in it all the time (Just to get rid of the 5000 bag I have) and they fly straight and far for being .2's.
I should also say I put a systema bucking on at the time of installation
Increased my fps by 10 -15 ~
Increased effective range by 20 ft or so at about 230 ft they start to fall
Nicely painted and well made with aircraft aluminum NOT stainless steel.
Madbull engraved into barrel.
None, I've had no problems with mine.
Rating: [5 of 5 Stars!]