Great project! - I've been interested in these little actions since Ross Seyfried wrote about one in .455 Webley [in DGJ]; I think he shot a cow elk with it! There's no engineering reason they should be any weaker than a square breech, and good modern steel and heat treatment is available now as well. I can't see much in the pics, but is your Alex Henry "oddity" an external lock? Left or right-hand?