Bubble level attaches to the muzzle crown tohelp you calibrate a Flatline Ops ADI, ACI, orother brand angle indicator. When the bubbleis between the lines, the barrel is absolutely level, so you know theindicator s reading will be accurate.
Bubble level attaches to the muzzle crown tohelp you calibrate a Flatline Ops ADI, ACI, orother brand angle indicator. When the bubbleis between the lines, the barrel is absolutely level, so you know theindicator s reading will be accurate.