This trigger should be compatible with the GHM9, however, the B&T has a wider receiver and not all drop in triggers will be compatible because of this. The Elftman Tactical AR10 trigger has been tested and confirmed to be compatible with the GHM9 and can be found by using the link below:
https://www.opticsplanet.com/elftmann-tactical-ar-10-trigger-curved.html?_iv_parent-gun-model=ar-10