How about the umarex 177 Smith & Wesson 6'', its a much better quality revolver. but a lot more money, but its built like a tank and if anything did need replacing in the future you can buy spare parts for them..
I have never been a lover on the revolvers with fake cylinders though like the umarex 686 or the 357 crosman, but the quality is definitely there with the umarex 686..
Its a bit different, but if your after a 'True' semi auto pistol, These are your best bet, they are not pellet, but as realistic as your get and both have fully adjustable sights, have a look at these..
Tanfoglio limited custom..
https://www.surplusstore.co.uk/air-w...ustom-177.html
Sig 226 S5..
https://www.surplusstore.co.uk/air-w...o2-pistol.html
ATB, Marc..
Some of my favourite guns in. You collection, Umarex Beretta 92fs - Colt Custom 1911 - Walther Lever Action - TM Hi-Capa Custom Build Project - Colt SAA .45 & many more..