I have managed to get 5 boxes (5 rounds per box) of .577 no 2 (2 13/16")Kynoch ammo for my Rigby double rifle. The ammo appears to be in excellent condition. In fact, only one of the boxes appear to have been opened. Even the opened box has no finger marks, etc. on it. Would it be advisable to shoot this in my quite high condition Rigby? Or should I pull the bullets and reload? Any advice would be appreciated.