If anyone can shed any light, ideas or theories on this at all, I'd be most pleased to hear them.
 
This nipple wrench is missing the cross arm & oil bottle dipper. The cross arm would most likely have a screwdriver tip at each end, one large & one small. If it is for the arm that I think it is for, then it wouldn't have needed a worm.
 
The shaft is marked with a small broad arrow & Crowned Enfield inspector number, so it is definitely British War dept issue.  
 
It will not fit over a rifle nipple, not even close, nor does it fit carbines or single barrel pistols which all take this same nipple size. So that leaves mainly the revolvers. �
 
Looking at R.E. Brookers "British Military Pistols" there were only two percussion revolvers issued, the Beaumont Adams & the Colt '51 Navy.
 
J. Holden's "War Dept Notes" describes (circa 1864) two types of caps being made, basically the regular large ones & those for the Deane Adams revolver, it mentions Colt caps being bought commercially.  
 
The "List of Changes" kicked in a little late for the introduction of these revolvers & doesn't help a great deal in identifying this tool nor giving clues as to its issue. But it does say that the Adams caps were modified & that this allowed them to be used on the Colt as well. So they had basically the same nipple size.  
 
From all the above logic says there must be at least two nipple wrench sizes, one for rifles, carbines & pistols & one for revolvers.
 
This wrench does not fit the Colt, which requires its own unique nipple wrench. Next I tried it on a WD marked Adams, & bingo, absolutely perfect fit, the slight tapering of the shaft end seems to be tailored for this pistol.  
 
There isn't a great deal around that I've seen about nipple wrenches, Blackmore, Roads & D. W. Bailey have all covered them to some extent. Has �anyone ever come across any other info?
 
And does anyone know what the Adams revolver was issued with nipple wrench wise?  
 
Thanks, Adrian.