Q: I have several early English revolvers made by Trantor, Wilkinson, Hills Patent, Webley Marks 1 & 2, Webley No. 5, Bulldogs and one pre-1900 Colt SAA in 450B. Fiocchi makes ammo for the .455 Mark II and a ".450 Corto" which I call .450 Colt. These are both very short cartridges. I am wondering if Fiocchi loads them to low enough pressures to be used in the pre-1900 handguns? In other words, are they loaded to black powder pressures? I have written them a few times but no reply. They also load some other odd and interesting calibers but I am interested in these first.
A: It sounds like you have a neat, enviable collection there. Those are some nice guns. I've fired both Fiocchi .455 and .450 Corto (.450 Short) with good results from English Webleys and Bulldogs. One caveat is the condition of the gun. Guns designed for black powder often have greater headspace and barrel/cylinder gaps with a little endshake thrown in for good measure. This is necessary to keep the revolver from "fouling out" as the black powder residue builds up. If these tolerances are excessive, smokeless powder loads can beat up the gun in short order. Personally, I no longer shoot smokeless powder ammo in guns originally made for black powder; but the .450 should be gentle enough for older guns if they're in good condition. Have a gunsmith look them over if you're in doubt. The .450 can be fired in guns chambered for the .455 Webley.
I'll bet some of your guns have a "Nitro Proof" mark, which is a tiny crown over NP mark. Those guns, if safe to shoot, would be safe to shoot with the Fiocchio ammo.