I recently acquired a Webley mk1 still in .455, the frame is in excellent condition but the rifling appears to be very weak, possibly from a previous owner shooting jacketed bullets. A friend suggested finding a replacement barrel, I'm fairly new to antiques but I believe if a mkiv or mkV barrel would fit I could source one for less money. Has anyone tried this before, or have information they could share with me? If so I'd live to hear it, thank you.