That is some great information, I downloaded it for future reference. I do have some general questions, I have some gun experience but mostly handguns. I recently retired and am taking up long distance shooting, or I hope it will qualify as long distance. To that end I have purchased a Barrett M82A1, mainly because I have a fairly large quantity of 50BMG ammo from an old purchase, then have been told to forget it because I will need match grade if I want to do anything out over 500 yards. So, I asked some friends who were in the military for scope advice and saved and saved... and saved some more to buy a Leupold Mark 5HD M5C3 Tremor. I am told that should work but that it isn't tough enough for military use, which I am fine with as I am not military (they had standards) LOL, anyway what I am looking for is any advice on where to get some training, do I need to have the scope mounted by a gun smith, I have heard the 50 will cause it to move around if you don't. and do I need match grade ammo to get started? The ammo I have is military production. some red tip, silver tip and just plain. Thanks for any help.