Due to the internal shape of the contact patch, there are some barrel requirements that must be met. This bucking was designed to be compatible across a large spectrum of barrel brands. However not all barrels will be compatible. To check for compatibility, one must only ensure that the barrel window meets the minimum dimensions shown below. Ideally the corners of the barrel window should be squared, however the TruSight Airsoft team has tested rounded corners with success.
Here, you will find full detailed instructions (pictures included) on how to install the Gen2 Tru-HopTM bucking and former Tru-HopTM concave spacer:
Gen2 Tru-Hop Bucking Installation