IIRC, .455 Webley and .45 ACP are almost identical projectile-wise, so they could just be handloads.
That’s an Enfield No.2 Mk1 if I’m not mistaken, which means those are .38/200 aka .38 S&W hollow points. Pretty fucking...
FMJ .455? WHAT!!!!!! and it’s hollow point….want….so much want.