Castle Nut Wrench, AR-15, High Torque

I designed and used this wrench to remove a castle nut that was torqued to spec at factory (approx. 40 in-lbs, per TM 05538/10012-IN). I tried many other designs of 3D printed castle nut wrenches, but the teeth would always shear. After eliminating the weak point, this one worked!

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Requires 3x M3 screws, I suggest 12mm or 16mm length, and I recommend socket head cap screws to allow you to screw them in with your fingers.

Printed in PolyMaker Polylite ABS with .20mm Strength profile, only change being infill was switched to Gyroid. Any non-flexible filament type should work for this, however I recommend using this same strength profile. 

After printing, Tap the three holes thru to M3 x .50. Self-tapping with M3's may work, but I had a tap so I haven't tried it. 

Screw in the three screws until the tips are within the profile of the castle nut cutouts, but do not tighten to the point where they touch your buffer threads or damage may occur. Two full-turns back from screw-thread impact left a good safe distance when torque is applied as the wrench does have some flex.

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Yes, I do own an armorer's wrench, but I also enjoy seeing if I can solve problems through 3D printing. And I have a new printer :)