As far as accidents go, I wouldn' t be concerned, they are very rare, and most modern guns are made with safety in mind if something catastrophic should occur. Not saying that if you load a 30-06 round full of bullseye you are going to come out fine and dandy after firing it, but in most casehead failures, I wouldn' t worry too much if you are 20 feet away

I would worry more about shooting next to someone shooting a semiauto without a brass deflector or with a muzzle brake. Nothing wakes you quicker than getting a piece of hot brass down the back of your shirt, or being anywhere near a rifle with a compensator without hearing protection when its fired. I think the worst offenders are slug guns with ported barrels- these tend to throw alot of crap out to the side of the barrel. I' ve even seen a guy who was hit in the cheek by a hot sliver of lead that came out of a ported slug gun on the next bench over- steer clear of these guns[>:]

If the guy next to you is shooting a mauser 98, stay to the right of him, if he' s shooting a flintlock, stay to the left of him.