Janissaries by Jerry Pournelle

[MikeClark]

Pournelle was a friend of H. Beam Piper, and I think that Piper's Lord Kalvan of Otherwhen might have been a bit of inspiration for the Janissaries series. A similar set of circumstances to Kalvan, except that it is a platoon-sized Korean/Vietnam War period armed soldiers transported by aliens to a distant planet where humans live and fight using iron age swords and armor, rather than a modern police officer transported to a different timeline on Earth amongst the same.

Two of the three extant novels were cowritten with Roland Green. The first and fourth (not yet finished) by Pournelle alone.

Imagine what a recolless rifle would do to a castle gate, or what effect a few mortar rounds would have impacting amongst a cavalry charge. Imagine too that ammunition resupply is some light-years away and very very infrequent. Talk about fire discipline, and you better learn to wield a sword, too.