My friend I feel your pain. Your Mini is probably a 181 series, you can check the first three digits of your serial number to see. I'll tell you what you are up against.
This little rifle has a very violent action. Violent enough to shake most scopes to pieces in short order.
To solve this problem you can install a heavy recoil spring, available from Wolfe, Brownells, etc. You can also install recoil buffer pads but the ones I tried didn't fit well at all. much too thick. Then you will need to install a smaller gas port bushing (cheap). Which makes less gas available to work the action. Or you can go first class and install an adjustable gas port (not so cheap).
Second problem, there aren't any good bridge (receiver) scope mounts available for this rifle. The best is probably B-Square and it is iffy.
Third problem, the ejected brass is liable to hit your scope. Some rifles have this problem, some don't.
You can get an after market hand guard with rails that will let you mount a scope forward of the receiver, scout rifle style. These are a little pricy.
The factory sights on the 181 Mini are indeed an abomination. In my case, I just had a terrible time even seeing through the peep. I fixed this problem by reducing and reshaping the comb of the stock. This really wasn't a big job. Took a pleasant evening using sandpaper only and that included refinishing and blending the new comb. This made a tremendous difference. While the factory sights still sucked, I could at least use them. I next installed a ghost ring rear aperture in place of the factory leaf (peep). That's a five minute job. I haven't yet done so, but I intend to do a little work on the front sight, at the very least, I'll add a gold bead.
A red dot or reflex sight is great if you are shooting at people at fairly short range. But for a plinking rifle, I wouldn't bother. The dots are mostly 5 moa and that's too large for varmits, at least the small four legged variety. A smaller dot is very difficult to see against many backgrounds.
You will probably find that your rifle, even with a scope sight is good for no more than 4 or 5" groups at 100 yards. You can cut those groups in half by attaching a five inch or so metal rod to the barrel. Tri clamps are available from Cheaper than Dirt for ten bucks each, you'll need two.
Use any metal rod roughly the same diameter as the barrel. This is a cheap fix that will do wonders. If you want still better groups, bedding the stock will help some.
Hope this helps.
