I’ve shot a couple of mid-90s Mini-14s and they aren’t even as accurate as BB-guns because of the thin barrels. I have heard the newer ones have thicker, stiffer barrels and are much better.
Hence while the early models could “chamber” the 5.56 but it was not optimal, especially if you try to chug more than a cpl mags thru. Once again, if you can get a Bushmaster then I would absolutely recommend getting a mini too. Common sense.