For a fascinating paper on how the flow of guns developed in Arabia in the late 19thC. with some emphasis on Martini Henrys but involving politics and intrigue at the time and a distilled appreciation of the bigger regional picture ...
see
http://pdxscholar.library.pdx.edu/cg...en_access_etds
The author suggests collusion in using the slave trade to mask the ever growing arms trade used to import huge amounts of rifles through Arabia for Afghanistan among other recipients...