ArmaLite’s AR10 Vise Jaws are identical to the M15 Jaws, except that they are enlarged to hold any AR-10 Upper Receiver. As with the M15 Jaws discussed above, these Jaws clamp on the sides of the upper receiver.
--When using these Jaws, it is important not to clamp the vise too tightly. Doing so could deform the upper receiver. You can insert your bolt carrier with key (without the bolt assembly) in the upper receiver to provide additional support. But, still use caution.
-- Be sure to close the ejection port cover before placing the upper receiver in these Jaws.
Technical Note 90: ArmaLite Vise Jaws and Blocks