Caz/cc
Regarding the RAMC carrying arms, if this was done it could only be for the protection of patients, etc. International protocols did - and still do - permit it. In the ABW, I always understood that RAMC officers carried sidearms in the field. Corpsmen and bearers would not carry rifles; I have never seen them so armed in any pics of the period.
As to the gun in Caz's 21113, it appears to me a 4.7" Naval gun on a platform mounting (i.e., no wheels are visible - and if present, they were of such diameter as not to be missed!). I realise that the pic says "6 in. gun in redoubt". I think the caption is incorrect in that respect. The RN did supply a 6" heavy gun along with other, smaller types for the relief of Ladysmith (the seven ton six-incher situated on Gun Hill fired it's 100 lb shell to 18,500y or 10.5 miles). Such a large gun, however, was simply not readily portable. The Naval 4.7" guns were more portable (only requiring 32 oxen to move!) and after the Relief of Ladysmith and Kimberley, they were still used in support of the army until handed over to the RGA on 24th June, 1900. Thereafter the 4.7" guns saw service with the RA until at least December 1901.
Frequently, these large 4.7" guns were given nicknames/catchwords of the day and "bobs" would certainly be a tribute to Lord Roberts.
cc:
The practice of referring to large artillery pieces as "rifles" was adopted by the US military/navy. British artillery was always referred to as "guns". Each of my copies of Treatises on Ammunition for the period leading up to the ABW always refers to them as such.
The Boer "six inch" 155mm guns (Long Toms) were much lighter than the RN six inch jobs; however the Boers destroyed theirs as the ammunition ran out.
Sorry this email is so long. I intended it to be shorter!
IL.