The Field is a pretty strong action - amply strong for most rounds, actually. It also is pretty simple, consisting of few parts. I would call it the Brit Hiwall, being at the very least conceptually as good.
As to cartridges, .303 is period correct, but most were chambered either as a hunting rifle in some (BP or nitro) express cartridges (take your pick), or as match rifle in rounds like #2 Musket, and I presume even 577-450. Of course, such an action deserves to be chambered for a period-correct Brit round. I for one would have no qualms as to its solidity, it would be one of the few actions with external hammer I would like to have.
To put things in perspective, the Field action was used by quite a few famous names in the Trade to build rifles (Holland & Holland, Greener,...) so it was quite well thought of.
Joe, I believe it was Rigby who used the .45 2.4" and gave it a Brit name - shame on him!
Last edited by martinibelgian; 02/10/09 01:51 PM.