The barrel is very light and very well made... I think it is designed for AEP's and things like the MP7. I have been building an AR pistol with a full sized hop up and it seems to work well with that.
The window is tiny though and I had to fit the nub too it. WIll not work with flat hop and omega nubs etc.
Also increased my FPS by over 2... This was in conjunction with a new bucking and Prowin Hop up so can't 100% put it all down to the barrel. Worth bearing in mind.
Overall for what I am using it for it is a nice bit of kit.
.jpg "Excel BB 0.20g 3700rds Box of 10 (Bundle)")
