"Ignorance is bliss. Andrew Wyatt would you care to enlighten us on your thoughts of the mosin or are you just trolling?"
I thought I was pretty clear, actually, but i'll clarify further.
There are three lines of reasoning that in my mind make a Mosin a poor choice for a first gun.
1. A New shooter is learning gun handling and marksmanship skills that will stand them in good stead for life. A mosin has sights and safety that are inadequate, and this makes learning marksmanship and good gunhandling more difficult than necessary.
2. A new shooter's first rifle should be something they should be able to use for a protracted period of time. As such, the ammunition should be something that's available and easy to get not just at the time you give them the rifle, but twenty or thirty years hence, when they want to hand it down to their kids. 7.62X54R is in the same position 8mm mauser was in the seventies and eighties. It's not easy to get now, and 7.62X54R won't be twenty years from now.
3. A First Centerfire Rifle may end up being a kid's only centerfire rifle. as such, it should be as solid, dependable, and possess a useful level of consistent accuracy. Mosins can be made to shoot, but not as consistently as a modern rifle with a synthetic stock and bedding block.
With these things taken into account, If i were suggesting a new rifle, i'd suggest a one of the youth model Rugers (or the GSR) or Remingtons in .308. If i were suggesting a milsurp, i'd suggest an FR-8, Israeli Mauser, or a 1903A3.
If we're not limited to .30 caliber Bolt guns, I think it's hard to go wrong with an Ar-15.