Left a mark on the shoulder? Never had that problem with mine.
A few suggestions on the miss problem.
1. try a bigger target.
2. affix bayonet.
3. get some Q-tips.
4. try different ammo.
5. grab the rifle by the fore end, and use it as a paddle or a club.
Seriously though, i would try something other than Mil-surp ammo for better accuracy, and try affixing your bayonet. According to some, this helps. You are hitting high right, are you getting a fairly consistent group? If so, try holding low left by the distance you are off.
Welcome to Mosinitis, there is no known cure, but it can be treated with regular range sessions. The only warning I will give is this:
Do not be surprised when you discover that your M\N has cloned it's self during the night, this happens from time to time. This is generally not a problem, but they can breed like rabbits, taking over your gun safe in no time at all. Buy a bigger safe now.