All true. I would refer you to the nutnfancy vids on youtube "mini-14 vs. the world" or "mini-14 arrival of the underdog" he pretty much shows that in a defensive appilcation the mini will hold its own. Begin Nutnfancy flames in 3...2...1... LOLI'm a newbie as well, but from my limited time in the Mini 14 world, my answers would be
1)some people are against running steel case through any rifle they own, others are not shy about doing it. I think the consensus is that .223 steel case is handled by the Mini better than it is in the AR
2)Yes, there are a good number of Mini's that have no muzzle device of any kind. It might help with accuracy, as apparently the weight of a flash suppressor/muzzle brake can reduce the effects of barrel whip that occurs as the barrel heats up.
3)The earlier models prior to the 580 series (and some of the earlier 580's) have a thinner barrel, and apparently as it heats up, the groups expand. There are various fixes for that, from barrel supports (like the Accu-strut) to cryo treament, barrel replacement, and in some peoples expert opinion, "buy an AR".
Thank you. That helps. opinion on steell ammoGo to Ruger Mini-14 Serial Number History to find out year made. For rate of twist from chart below. It will most likely be 1 in 10". So a 55gr bullet or less will most likely give you the best Accuracy. Although some have found that a 62gr works well.
TWIST RATE FOR MINI-14
1978-1985 = 1 in 10" (e.g., 181 series)
1986-1994 = 1 in 7"
1995-2004 = 1 in 9" (e.g., 197 series).
2005- = 1 in 9"