Ruger factory metal mags, no matter what capacity, are always a solid buy, unless damaged. Older Ruger metal mags
might need their springs replaced. I bought a couple of metal, 30-rd Ruger mags back during the Ban days, which only needed new USGI mag springs to be fully GTG.
Some aftermarket Mini-14 mags
may benefit from installation of modern Ruger mag followers. Info on perfectunion.com.
Kinda tricky, and I feel for folks who are so new to the firearms scene that they did not see this coming.
You older folks? No pity for you; a blind man could see this coming, and so should you have done.
In view of election results, might be wise to buy some 5-rd or 10-rd mags in addition to normal cap mags, as "public" use mags.
perfectunion.com Mini-14 forum, is probably the best place to look for magazine tips, but
good Mini mags are scarce nowadays.
Personally, just exhausted Tapco Mini-14 30-rd mag supplies from a vendor. Equally good Thermold 30-rd Mini-14 mgs also gone.
Mini-30 mags, I dunno.
No mag is GTG until tested.
Good Luck!