VB Grenade Question

[EODGUY]

Just picked up a VB practice grenade with the typical red top. Everything is present and on good shape except there is no cal. .22 rimfire round. Am I correct in assuming that the practice grenade did not have the rimfire installed? I do not have any information on the round that goes into that ;eve; of detail.
Also, can anyone identify the "SU" marking cast into the body? The "U" is hard to see in the photo.

 

[Eodtek]

The casting should be US for United States. Our original stocks were French in origin. The "rim fire" round is referred to in the manual as a "primer".

The Ordnance Committee declared it obsolete in 1923. The only pub I have is from 1917 and doesn't address a "Practice" version, just a dummy version. The photo you are showing appears to be the explosive version.

 

[Millsman]

The latest I've seen was a French example dated 1937.

 

[Eodtek]

Here is the US Pub on the VB Grenade.

 

[EODGUY]

Thanks to everyone. I initially thought "US", but then thought that the guy making the mold had to make it as he saw it and not a mirror image. I also have never seen one marked "US". None of mine are either and at least two are US because they have Winchester rimfire cartridges. I also have never seen anything on the color coding of the VB's, but have been led to believe that the red indicated an inert version for training. That would also fit the color coding of the period, for example the Training version of the Mark II hand grenade was also red.