This Hammer Block is useful for doing trigger work on AR15’s without the danger of the hammer striking and damaging the lower receiver. The prototype was printed in PLA with a 30% infill and has survived over 500 hammer strikes so far with no apparent damage. Cost to print is about $1.25

In use: https://vimeo.com/146028726
Originally posted on grabcad you can find the files to download and print here: https://grabcad.com/library/salted-earth-ar15-hammer-block-1