As with much in life, having the right tools for a job makes everything easier. Most of us are guilty of "adapting" a piece of equipment to perform a task it was never meant to perform (like, say, using a screwdriver handle as a hammer...) Whether it's out of convenience or necessity, "making do" is very rarely the best way to handle a task.
When building an AR-15, having the right tools is mission-critical. Using the correct punch means roll pins are installed correctly, detente springs don't go flying into the great blue yonder and everything goes together as planned/expected. Trying to cobble things together using vise grips and a multi-tool is going to yield less-than-spectacular results for most people.
Using a dedicated piece of equipment like the XS Sight Systems AR-15 Armorer's Block means you can work on an upper receiver to install optics, change the muzzle brake or even build the upper from parts. The Armorer's Block clamps into a bench vise and locks down both AR-15- and AR-10-style upper receivers using pins in the takedown-pin holes. The Block locks the upper down to make installation that much simpler.
At first glance, it might seem like a limited-use piece of equipment, useful only for building an upper receiver, but there's another important facet. With this block, you can install a red dot sight or riflescope with ease - the block allows for a rock-solid mount that, critically, can be leveled for proper sight installation. You could even bring it to the range to help boresight your new upper (or an old upper with a new sight).
That's a lot of utility for a $75 Armorer's Block.
