HBi,
Yes, I did use the lighter spring. I used the lighter included replacement spring from the start so I never compared it to the heavier spring.
In the image below, the (A) points to some of the paint scraped off of the handguard. The silver strip (B) is where the edge of the new handguard stripped the hardcoat anodizing off the charging handle.
In the next image, you can see where (D) the charging handle scraped the surface. The other side (C) is just for comparison of what it looked like before. I used a sharpy to repaint the scraped surface. It's got that purpley black ink look to it but it cannot be seen in most lighting situations. I play things safe, which is why I started with the lighter spring. I also started with some grease in the charging handles channel because I thought that's where the friction problem would originate. I didn't anticipate it rubbing on the outside. After I identified the source of the friction after about 3 pulls, I greased the area (D). There wasn't much damage at that point, but after about 20 energetic pulls on the charging handle, it became clear that I'd have to use the factory charging handle. No problem after that.
I'm very satisfied with my purchase. It's exactly what I wanted... until someone mentioned the k-style package. bleepit.
If you make a barrel, fixation and k-style hand guard package, sign me up. Even better if it comes with a threaded 3-lug.
Jason