...feel my friend should buy "new" to get the warranty... .
This advice will most surely cause your friend to pay top dollar for a cheap rifle... arguably the worst kind of deal possible.
For the same money he'd spend on one of the cheapest, entry level rifles, he could get a much better quality, used one. Buying from a reputable seller, or having a professional do a pre-purchase inspection will be all the guaranty he'll need.
When was the last time anyone needed to use a warranty on a new firearm?
