[NorthernDave]

Me and a friend were testing his M249 after fixing a short, we dry fired 10 - 12 rounds and heard a loud grind noise, after we opened it back up and removed the mechbox to open that up as well we found that the piston had 5 of its teeth ground off and torque up sector gear was also missing 2 teeth and the staft that the gear rotates on was snaped off.

Does any know why this happend and where we can find a higher quality replacment part (this will be the 3rd piston to be changed) ?