Not sure if this helps or not...
On pages 22-23 of the "The Navy Luger" book by Gortz & Walter...there is some discussion as to whether it was plausible to consider five (5) 15 cm barreled experimental B-suffixed 5-digit prototypes (which I read to assume were in 7.65 mm...) were actually Navy experimental pistols or not.
Another sentence reads, in reference to gun # 10005 (a 17.5 cm barrelled, 7.65 mm, with a rear tangent-type sight and unique stock attachment with a push button release), as :
"...It would have been very tempting to consider this gun as a potential navy trial piece had its calibre been 9mm rather than 7.65 mm...".
Maybe the conclusion has been accepted by some, including this Dutch collector...
Regards,
Pete... <img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" />