When I received my Recoil reduction charging handle I followed the instructions provided (including watching U-Tube videos on the pin installation). All went well until I slipped just before final pin install and dropped the retainer into the spring, which makes the installation next to impossible. After many F bombs, and hours of playing with this spring, I was about to give up and send the whole thing back to the company. Then I thought, your a Missile engineer, there must be a way for an old guy to do this with less strength, and more brain power. Well i can happily say that I was successful after making slight mods to my vice. Installation was easy. I have included pics for the brotherhood. Hopefully this can help someone who might be as frustrated as I was!