Let them know what you think of them.
Colt’s Manufacturing Company http://www.colt.com/
Barrett Firearms Manufacturing https://barrett.net/
Bushmaster Firearms International https://www.bushmaster.com
Caracal International http://caracalusa.com/
C.G. Haenel https://www.cg-haenel.de/en/
Heckler & Koch http://heckler-koch.com/
Remington Arms http://www.remarms.com/
Sturm, Ruger & Co. http://ruger.com/
SIG Sauer http://sigsauer.com/
Smith & Wesson http://smith-wesson.com/
Springfield Armory, Inc. http://www.springfield-armory.com/
My message to these companies:
Why are you selling weapons to civilians that are designed for warfare and end up being used in mass killings?
You are worse than murderers: too cowardly to pull the triggers yourselves, but happy to profit from the carnage.
You are despicable.