You might like
Her Majesty's Wizard by Stasheff (no e-version that I've ever found for that one, though), Or the Ring Of Fire series, the first one is
1632, no magic in that one, though.
Going somewhat the other direction,
The Excalibur Alternative is a good read.
The Belisarius series is
kinda in the same ballpark, the first four books in it are in Baen's free library, as are
1632 and
The Excalibur Alternative
You also might find David Weber's "portals" series, the first one there is called
Hell Hath No Fury
Those should give you a few directions to look.