Re: I have made a terrible mistake.
When I bought my 183-series Mini-14 back in mid-1982 I paid $280 OTD with one Ruger 20-round mag thrown in. Since then I've been happy with it in that it never fails to shoot and it will digest any ammo & accept any mag. I choose to use. Over the years I've collected about 10 metal 30-rounders that all seem to work fine in my gun. They snap-in and lock in place just like the Ruger factory items.
I did put a Mo-Rod on the gun to quell the tendency to have barrel whip and wandering POI when the gun warms up under rapid fire. With the Mo-Rod in place the gun is a consistent & reliable 2" shooter at 100 yards now. The one big downfall of the gun is that I haven't found a reliable way to mount a scope on the old model Mini, so I'm stuck with using only iron sights. It's more challenging for my old eyes.
I got a very nice AR-15 last fall that is very accurate and reliable. Excellent modern metal 30-rnd mag's. with magpul follower are redily available for under $10 and mounting a rock solid scope on the flat top receiver is a piece of cake. I have over $1,000 in the AR, as outfitted, though.
I still love shooting my Mini-14, but the AR is a REAL battle rifle.
Fear is a reaction..........Courage is a decision