I was checking out some stuff the other day about the Columbine shooting, and I learned that in the video of them testing their guns at a shooting range, both boys complained that their sawed-off shotgun hurt to fire and in some cases left cuts and/or abrasions on their hands. As my current WIP novel deals with an anti-government revolution, I had figured that the rebels might likely "saw off" weapons like shotguns and rifles in a similar fashion, to make them more modular and easier to conceal. But I didn't think that doing so could cause injury to the shooter. If that's a common thing, then it may pose a problem for my characters. I'm gonna need someone with firearms experience to tell me - is this a fairly common issue with illegally-converted sawed-off weapons, or did the Columbine kids just do it wrong?