I guess that I should have said not made a true 28ga. frame in any earlier O/U boxlocks. I thot it apparent when I made ref to the AS & BL series guns.
I'm still not positive that the higher grade newer 28ga. guns are all that small, but I don't own one to measure. I do have access to the local Beretta Gallery & their main gunsmith is a friend, so I'll ask him about that next time I get the chance. If someone reading this has one, perhaps they could measure the distance between the firing pin centres & post it.
Now that the subject has come up, it might be fun to measure as many small 20 & 28 ga. O/U's and see where their respective frames sizes fall.
The small frame Miroku/Daly's had 3/4" spacing between the firing pins according to most refs, but I strongly suspect it is actually 19mm since they were JIS mfg. before becoming ISO; both standards being metric. If you are using an inch tape measure 3/4" is what you'll read.
FWIW, placing two 28ga. hulls side by side so that they are touching at their rims, it would appear that 17mm's is the distance between centers; in other words, you can't get any closer than that on the firing pin spacing & still use two 28ga. bbls.
