The main worry on the ruck sack idea is not so much that it would get crushed, but also that it would get scratched, a lot. Cordura will not be nice to armor. I had to transport my armor up to the Great Wall in China in backpacks, but that was a one-off and it was painted armor, so I didn't mind so much. As John & Sierra noted, long term it's not a good idea and a hard case bin or box is a better way to go.