Good Evening, Lord Eoin!
Yes, seems I am the primary representative of the British Empire in GAF (.... although some members residing in the U.S. have begun moving in that direction for their impressions of late ....) and have definitely been known to wear a kilt for Mess Dress .... and also in the field -
As Drydock indicates, to just join in with GAF and have fun, any suitable firearms will fill the bill, since you can shoot with your cowboy action guns and duds in "Scout" category. However, the trend in GAF military shooting categories really seems to be to match the firearms to the military impression as much as practicable .... both in terms of nationality and of era. For A British Empire impression the ideal firearms, of course, are British .... the exact ones to shoot being dictated to a large degree by the particular era being portrayed. For what it may be worth, for a
Canadian military impression, although our rifles have pretty much always been the same as used by the British army, U.S. built (or at least designed) handguns were the norm, at least for those issued to the ranks - 1851 Navy (London Model, mind you) from 1855; Model 1878 Colt Double Action in 1885, Colt New Service in 1900, and so on. Uniform, for the most part, is very similar to British - in fact my Mess Dress impression depicted above is a Major of the 5th Battalion of the Active Militia of Canada, circa 1890 - "The Royal Scots of Canada", now the "The Black Watch (Royal Highland Regiment) of Canada".
Feel free to ask any specific questions .... either here on the forum or via PM to me ....
Yes, I've been "mentoring" Ned a mite of late in some Australian impressions he's been putting together, and believe I was also of some small assistance to "Guns Garrett" in putting together his 1st (King's) Dragoon Guards impression, circa 1880-81 (First Anglo-Boer War) -