That's a good question Peregrine! We certainly had them in the Armourers shops but I don't think that they were part of the gunners kit. They MIGHT have been initially but not in my time. There were actually two different sets the early and later set. The trouble with giving these sorts of hard, reaming tools to the gun crews is that they use them for, well, a bit of hard over zealous reaming!

The modern day equivalent is the drill bit - as in the SA80 combination tool. Just long enough to do the job but NOT long enough to do any damage. But, alas, just long enough and snap off in the gas block!