IJ58 and the later IJ43 ara about indentical.
One feature that I (as a European) thought would make them popular with US buyers is the copying of the Winchester 21 action. Oddly it is almost never mentioned. Maybe most people do not know how different a Mod 21 action is from the traditional Anson-Deeley and assume that all boxlocks are the same internally.
Both the 58 and 43 are plain (being polite) but durable doubles. Some friends own them and have used them hard for decades without problems. I wonder if the durability is due to the coil sprung action borrowed from the MOd 21, or maybe it is the steel grade used, because it definitely is not due to refinement in finishing.
A gunsmith friend rebuilds both the IJ43 and the IJ27 OU, turning them into ribless bespoke doubles weighing 6 lbs or so and very handy.
