Unless I am greatly mistaken, the mount pictured above is originally intended for an M-14/M1A rifle. The dovetail at the rear of the mount is supposed to interface with the dovetail on the M1A/M-14 that originally held the stripper clip guide. Dead give-away.
If you had some mount fitment issues with your Mini-14, that might explain things.
See if you can find some "maker's marks" or names on the mount, and report back. If you are lucky, and if the mount is not buggered-up, it could be worth up to about $200 to the right M-14/M1A owner on a gun forum or on ebay. NIB M14/M1A mounts from top mfrs are about $340.
PLEASE tell me that you did NOT permanently alter the Mini in order to fit the M-14/M1A mount!
There is a similar sight mount made for the Mini-14, but the ones I have used were made of flimsy aluminum and I am not aware of any such scope mount of this type, which is intended for the Mini-14/-30, that I can recommend.
The B-Square Mini-14 scope mount is likely the best option open to you, given your model of Mini, which does not accept most optics gracefully. That's why the later "Ranch" model of Mini was developed. Unfortunately, the B-Square mount is now out of production, but there is one on ebay for about $55. It's in blue, but (rare) silver models exist. If interested, suggest you do some investigation and see if that specific model of B-Square mount will fit your 182 series Mini.
Nowadays, most non-Ranch Mini owners seem to have gravitated towards using Red Dot sights (RDS) mounted with a Quick Release (QR) mechanism atop a "Scout Rail" offered by either Ultimak or Samson. The rail offered by Amega Ranges is well-made but is notably "higher" than either the Samson or Ultimak.
The idea behind this "scout" type rig is to allow the user to have the optic set very low in order for the user to get a good, quick, natural cheek weld without delay. If the optic is low enough (Bushnell TRS-25 or TRS-26 (preferred)) the user
may be able to see through it and use the original iron sights. If not, just remove the optic via the QD lever (or other attachment device) and use the iron sights. It's nice to have back-up sights.
This set-up will involve some expense on your part. However, after trying a set-up very similar to the one you are trying, the Ultimak + RDS is miles ahead, to my mind, and to the minds of other users as well. Your call.
Be careful when buying optics for your Mini. Most optics come with a very high "adaptor" intended for use on AR-15 type rifles, but some optics can be used without the adaptor or perhaps have optional low-mounts either from the mfr, or as aftermarket units. RDS are not friendly to folks with astigmatism, so suggest getting your eyes professionally checked--Good idea in any event. Accurate shooting begins with good vision.
Many people at
Ruger Mini-14 and Mini-30 | Perfect Union have come to feel the same way as I do about the "Scout mount" concept. Member sandog has many pix of his Minis with scout rails and RDS pictured there, but you will have to search for them.
Another forum you might investigate is
(2) Ruger Semi-Auto | Ruger Forum
IMHO, the Mini is a short-to-middlin" range carbine, and the Scout rail+RDS makes the most of that platform without adding excessive weight/bulk. Minis usually don't benefit much from high-magnification optics, IMHO.
I have given you much to think about. OTOH, I have gone through the same process you are going through in the past, so what I say is said from personal experience, not guesswork.
Your personal preferences may differ, and that's perfectly OK. Just offering you the benefit(?) of my experience and all best wishes!