1. Any tips of shooting rifles with a scope? I've only been out twice, though my results have been pretty good (about 2-3 inch groups, my first time firing a scoped rifle, not ideal and certainly not what I'm hoping for with some practice, I would like to keep it inside 1.5 inch groups), I have yet to take it out past 50 yards. A very nice man at the range helped me to sight in the scope, but I would like to have it sighted at 100 yards ultimately.
I can't see your pic .....
Advice anyhow:
1. Make sure your stock comb is the right height for your scope height. Stand with the rifle at "low ready", looking at a taget. Close your eyes, mount the gun, open your eyes. Are you looking through the scope with a full feild of veiw? How is the eye relief? If you open your eyes and have to lift your cheek off the stock to see through the scope (scope/comb height issue) or have to move your head forward (eye relief problem) to see, you should get that fixed. There are comb raising kits to raise the comb height or maybe lower scope bases (and possibly a smaller belled scope). Having your head in a consistant place with good cheek to stock contact will help practical accuracy in field situations. Dry fire is great to train you to find a target in your scope without a lot of searching around, because that buck of a lifetime may not wait around all day for you to find him in your scope.....
2. Once you have established that you gun/scope/load can predictably put 5 shots in a decent group from the bench, leave the bench behind, and work on YOUR ability to shoot up to the ability of your rifle: there are darn few shooting benches in the woods, so work on field positions, and learn to use a shooting sling ....... Include getting into field positions quickly. Generally, I have found the prone position pretty useless, as there is often too much brush or tall grass to use it (plus, it is slow to get into). Sitting, kneeling and "combat squat" work best for me. Practice, practice, practice....
3. To that end (more practice), you might look into handloading. 8mm Mauser is, as others have noted, underwhelming as loaded by US manufacturers, in deference to 8mm guns like mine (Bubbafied 1888 Commision Rifle). 8mm Mauser is pretty versatile, akin to a .30-06, but it does better with heavier bullets than the-06 ....... If you handload, you can make reduced loads to use on your 25 meter range ....... or load 220 gr for bear or moose......