as for the grenades ya they are pretty loud....i wouldnt go as far as to say permanent hearing damage...i threw one about five feet away...made my ears ring a lil but nothing more that shooting a .22 with out ear plugs... [smilie=armata_pdt_06.gif]
5 ft away, and 5-6feet up (it's on the ground and you were standing up, I assume) = 7 and some change feet away = .22 without earplugs. I don't doubt that.
3 feet off while prone would more than quadruple the effect. 1 ft off while prone more than quadruples the effect again (it's possible that you make a long throw and it lands right next to someone that's laying down right as it goes off) and your hearing could be impaired for the rest of your life.
Increase the effect by say... coming up to one of our games in Prescott, or using it during the summer, and the sound level is increased, and likelihood of hearing damage also increases.
I'm not saying "OMG you're going to make everybody deaf if you use one of those, no matter what every time!" or anything. Just know that you need to be extremely careful because the chance for permanent injury is there. I'd hate to be the guy that reduced someone else's hearing, or had my ears messed up more than they are.
I try to not be a dick about grammar and spelling... usually... but repeating the same word when it is incorrect drives me bonkers, and makes me turn into a meanie head. lol.