Whit my rem varmint I have no problem killing my target at 300M (bipod, Leopold base and ring) Free floating barrel mean that the barrel touch nothing he his not restricted when he wipe (barrel move a bit when fired) you won't see that, that mean more accuracy.
Yes you can have 4 rounds in the internal magazine + 1 in the chamber for a grand total of 5. If you want to do target shooting it does not Mather, the first one his the one that count.
The stock his crap, but if you are new, it does not Mather, you will pay at least 200$ for an other rifle whit a stock a bit bather, but in the end you will probably change that

so save the money get a 700 varmint in .308
If you really want to have a free floating barrel whit the riffle go whit the savage 10 FP, stock his not really bather, but it's free floating.
Scope number the first 2 are the magnification meaning that it goes from 3 to 10X the last number his the size of the lens the bigger it his more light will come in.
If you want I can take some pic of mine and show them to you this weekend