TOP SHOOTER CNC Aluminum Hop-Up Chamber Set for SIG AIR M17 / M18 GBB Airsoft

Great customer service !!

Nice. Easy hopup adjust.

Although the price is not cheap, this product is worth it.

It's been a few days, but so far it's not worn out and looks good. I think I fired about 30 rounds a day.

The Top Shooter CNC hop up chamber for the SIG M17/18 has a great quality, everything fits precisely. BUT as I had to find out after hours of testing, there seems to be a serious design flaw with the larger gear which moves the tensioner:
Between the teeth of the gear is a stopper, preventing the gear from turning over when moved by the smaller gear below. On the original gear (black) the stopper is placed on the opposing side of the ends of the groove. On the Top Shooter gear (silver) the stopper is placed at the ends of the groove.
This means the tensioner always presses on your bucking, but never full, and you don't get to perform a full rotation of the gear.
Besides i noticed my M17 lifting shots by roughly 10cm at 10m (even with the original gear) compared with the original hop-up chamber. Take this info with a grain of salt since I'm using modifications like the Nine Ball fixed outer barrel.
If Top Shooter fixes design flaw in the gear I still might buy this chamber again because of it's great quality, then it would be five stars, too.