Very unusual bayonet, 19mm+ barrel ring???

[hottoddy]

At first glance Me and my buddies thought this was just another Japanese bayonet, but we realized that it has a very peculiar feature.



A normal bayonet ring has an inner diameter of about 14.15mm, this one has a inner diameter of around 19.5mm! This doesn't sounds like much but just look at it in comparison!





The top bayonet is the one in question:


Also, why would it have a ball at the end of the quillon as opposed to the normal hook? The slot on the back is also about 1mm bigger than the ugly chromed arisaka we had next to it for comparison. Is this some foreign contract? Is it just for a big Japanese gun? We are all stumped.

[blinky]

That is an odd duck!
It's a Type 30 bayonet converted into a Murata Type 22 training bayonet for use with the Murata rifle.
I had to double check with the Labar book to confirm, kind of unique

[hottoddy]

Is that so? When do you think this would have been done?

[blinky]

Probably around the turn of the century into the 1910s.