I have a 223 Handi w/ heavy barrel. After a few trips to the range and a little tinkering, it is shooting 1" or better, 3 shot groups from 100 yards. That is with factory Winchester White Box ammo.
Pretty much everything I have read about the 45-70 Handi has been good. The triggers are pretty easy to lighten if necessary.
A lot of info here if you would like to read more.
http://www.go2gbo.com/forums/index.php?board=126.0