Not sure what Kyrie is talking about with XXV being a different action than the #4 Deluxe but all of the boxlocks currently built by AYA are the same mechanically speaking. The actions are, however, shaped and engraved differently.

#4 or 4/53. Simple scroll engraving with straight back action.


#4/53 Classic (from Cabelas) or 4/25 (from New England Custom Arms). Same straight back action as standard #4 but engraved with full coverage scroll (more continental style).


#4 XXV. Notice the same engraving as the 4/53. But with short barrels and Churchill rib.



AYA #4 Deluxe has a scalloped action with beaded fences and is engraved with more English style scroll.



#4 Round Action (available in US as the "Bournebrook"). Similar style engraving as 4/53, XXV, and 4/53 but is fully hand-engraved and over a rounded body.



#4 Ovis Uplander. Again same engraving as 4/53 and XXV but with same action shape as the deluxe (with a scalloped action and beaded fences).