Hi,
While the explanation given by Jeff makes perfect sense, there's an odd thing. In OpNav 1667, in the section that treats the mortar rounds itself, the proper type of fuses is indeed mentioned to be Type 93 and Type 100 (no mention of Type 88 fuses), the entries on the fuses themselves may be somewhat confusing. The Type 93 fuse is properly listed as being a.o. for 'mortars', but for the Type 88, there's mention of there being a 'Gun' version and a 'Howitzer - mortar' version, which requires less set-back to move the arming collar backwards. No mention whatsoever here either about the Type 88 being suitable for mortar rounds...
Some theories as to why one may still see these fuses often on those mortar rounds:
-Perhaps such documentation, particularly the term 'Howitzer - mortar' , in combination with the fact that the fuse fits, may have been confusing for collectors putting them together from spare items.
-Or, perhaps a bolder explanation, could it perhaps be the case that the Type 88 fuse is much more ubiquitous, and that the Japanese have perhaps found a way to arm the fuses manually (though I don't see how they could easily arm then when requiring rotational force), and perhaps used those, by lack of the proper types?
Now, while candidate explanation #2 may sound ludicrous, and admitted, I don't see how they could arm a fuse requiring rotational force by hand, there is one thing that intrigues me. If you observe the attached pictures, you'll see an 81mm mortar round that I have incoming.
Now, the official story behind it, as it was told to me, this round is a WW2 vet bringback. Not only that, but according to the person (whom I've never spoken in person!), the round ricocheted off of a lava crop, and landed next to him. Again, according to that person, the damage you see on the fuse and the mortar body, is supposed to have been caused by this ricochet.
This story already sounded somewhat incredible to me, and your explanation on the fuses, in combination with the fact that this mortar round is equipped with a Type 88 fuse, most likely disproves this explanation. Also, the safety mechanism still seems to be in place, or is this of the kind that breaks up by the impact?
Anyway, it should be interesting to find out 100% for sure, but I too do assume that Jeff's explanation is the only correct one.
Cheers!
Olafo
