They are certainly not as common as doubles but are to be found here in England. Mainly they are big bore singles; 4, 8 and 10's with a few 12 magnum 3" chamber guns. I suspect that is because they were sold a little cheaper for use as guns for wildfowl shooting where fewer shots are taken during the course of a year. I actually find that 16's and 20's are about as commonly found as 12's. Some .410 singles started life as rook rifles but later bored out. I sold an interesting single on recently. It was marked E.Thomas, Maidenhead, Berkshire and had a Jones underlever and back action lock. Originally it had been a 16 bore proofed for black powder but then someone had had it bored out to possibly remove pitting but then re-chambered it to 12 bore and were then able to leave a small amount of choke. It was then submitted for 2 1/2" nitro proof which it passed. It had lost a bit of weight in the process so was best shot with correspondingly light loads. It shot o.k. but was a bit lively towards the front end as to balance. Lagopus.....
