i got mine from x caliber in the us ordered for 449 plus exchange and about 60 bucks duty by the time i got them, i purchased the set of 8 i have tried them all, with a fn double barrel, a baikal break barrel and my dominion arms double barrel, you can fire 22 l,s,lr, 9mm, 38 special, 357 mag, 40 s&w, 44 mag and 44 spec, 45 acp, 45 colt, 410 guage shotshells and slugs, 20 guage shot and slugs, very versatile, some inserts are way more accurate than others, my favourite is probably the 9mm it is quite accurate, they are alot of fun for sure, especially with the short dominion arms, being as the round never touches the barrel, the short barrels only drawback is with accuracy as the sights are quite close together, and it takes a bit to get used to, the 357 mag and 44 mag i found to be a little out there for accuracy, i am still yet to figure that out but in time i am sure i will. hope this helps, i did notice the whole set being out of stock but they also sell the individual calibers you have both mentioned, it is quite a trip showing up at the range with a 27" double barrel 12 guage and messing around with 12 different calibers it attracts a crowd everytime...lol