Now to talk about the rattle, the ATC utilizes three accutite screws, the forward one has a polymer bushing, the two rear ones are metal tipped and push into both of the upper lugs. The ATC also comes with a set tool thats extra long. Unlike other Saints you can adjust all Accutite screws without removing the pistol grip…meaning you can adjust it on the fly.
The hole for the front screw, this will make it easier to remove the upper handguard. But if it is loose to be able to easily remove the handguard it will rattle. If it is adjusted tight it is almost i possible to remove the handguard.
Here is a look inside the lower handguard showing the screw.
Moving back here is the lower by the front takedown pin and the accutite screw for the front lug.
Here is the oustide of the lower showing the hole for the front adjustment screw
Now further back to the rear screw which other Saints already have, but this one is an upgraded accutite screw.
An update over older SAINTS you can now adjust the rear screw without removing the pistol grip, thanks to the extra long provided tool. This means you can tighten the upper and lower fit tight tight tight, but loosen the screw on the fly for easy disassembly. Huh

it almost seems like someone thought about all this stuff.
A look down the pistol grip, the small hole in the back is for the accutite screw.