Modular Maintenance Block Kit AR-15 / AR-10


Product Overview

Meet the ultimate builder tool for both AR-15 and AR-10 platforms.  Firmly holds both uppers and lowers, for both the AR-15 and the AR-10 rifles.  

We made this design because we've owned clamshell holders before, and got frustrated with them.  Now they are in the garbage.  This is not only stronger, but with one block you can fit all the different upper patterns, including lefties, and any lower on the planet because of the adjustability we designed into the blocks.

The modular blocks have nylon set screws to adjust for precise fit in each magwell.  Everyone knows not all magwells are created equal.  Some are broached, some are EDM'd, some drilled out and milled and all are different sizes slightly so every tool until this point was a bit of a compromise.  Now we give you the ability to make the tool fit the job perfectly and hold securely.  

It's all about the details too...

We use this tool every day here at Crosstac so we machined ledges into the base to rest on the vise so the blocks automatically sit level.  Comes with our precision CNC stainless steel pin driver that everyone loves.

Fully machined by us out of solid stock, then type III hard anodized for long life. 

This kit includes:

  • AR-15/AR-10 modular base block
  • AR-15 lower receiver block
  • AR-10 lower receiver block
  • AR pin driver
  • Pull pins and hardware


Warranty Information

  • Modular system comes with Base, AR15 block, AR10 block, pin driver, hardware kit
  • Base fits AR-15 and AR-10 uppers
  • CNC machined from solid 6061-T6, type III hard anodized
  • Blocks mount both parallel or at 90 degrees to the base for ease of working on firearms
  • 100% made in USA by the dedicated at CROSSTAC

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