Mounting of gun muzzle devices

Claim 1

APPARATUS FOR HOLDING A GUN MUZZLE ATTACHMENT AND A GUN BARREL HAVING A MUZZLE END AND A FIRING CHAMBER END WHILE SAID ATTACHMENT IS BEING SECURED TO THE BARREL, SAID APPARATUS INCLUDING A SUPPORT, A FIRST FIXTURE MOUNTED TO SAID SUPPORT AND CONSTRUCTED AND POSITIONED TO ENGAGE AND ACCURATELY LOCATE SAID FIRING CHAMBER END OF THE GUN BARREL, AND A SECOND FIXTURE MOUNTED TO SAID SUPPORT FOR HOLDING AND ACCURATELY POSITIONING SAID MUZZLE ATTACHMENT AT SAID MUZZLE END OF THE BARREL, SAID SECOND FIXTURE BEING CONSTRUCTED TO HOLD SAID ATTACHMENT IN ALMOST EXACT AXIAL ALIGNMENT WITH THE MUZZLE END OF A BARREL HELD BY SAID FIRST FIXTURE BUT AT A PREDETERMINED VERY SLIGHT UPWARD ANGLE RELATIVE THERETO AS THE BARREL AND ATTACHMENT ARE SECURED TOGETHER, TO COMPENSATE FOR THE PRESENCE OF THE MUZZLE ATTACHMENT IN AIMING, THERE BEING MEANS OF INDICATING PRECISELY WHEN SAID SECOD FIXTURE AND ATTACHMENT ARE AT SAID PREDETERMINED VERY SLIGHT ANGLE TO THE MUZZLE END OF THE BARREL.