Hi, saw the post and was relived to know I'm not on my own. I purchased my Allan back in the summer and replaced the firing pins and return springs and started shooting low pressure nitro shells at clays with much success.
Since then i've found out the origin of the gun was Birmingham as can be seen in the "dolly head" on the barrels significant to the area, it would have been finished and sold from Glasgow.
I now load and shoot black powder loads with it to some effect on a shooting ground and this weekend had a decent pheasant and a fast crossing partridge with it
Only problems i've encountered is remembering to cock the hammers and waiting for the smoke to clear !!