I believe the rear cylinder gap is way to wide for the firing pin to even touch a 455. No mention of a serial number on the rear of the cylinder yet? 45ACP require a moon clips that takes up a lot of space, so shaving the cylinder or recoil shield is required to allow for this caliber. Image is that of a original 455 on top and a shaved cylinder to accept 45 ACP on bottom.
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I can definitely test the .45ACP/moon clip aspect. No .455 on hand and unlikely I can get some before mid October.
Hi Gary,
As you know if 45 ACP is chambered in an ACP cylinder w/o a moon clip, the case mouth will headspace on the shoulder in the chamber and fire because the shoulder will prevent the round from chambering too deep for the firing pin to reach the primer.
The same thing is true for the long 455 MK I cartridge because S&W seems to have chambered their 455 cylinders for the longer MK I cartridge so that all 455 cartridges can be used including 455 MK II, 455 Eley, 455 Wesley, etc.
Gary, I was referring to chambering a 45 ACP in an original factory ACP cylinder, not a converted 455 cylinder. ACP can be fired w/o using moon clips.
Similarly 455 MK I can be fired in a 455 cylinder that’s been shaved to shoot 45 ACP with moon clips.
I was not sure. I guess we do not know what the OP's gun started life as yet, but dropping the 45 ACP into the chamber will tell the tale on whether it started out as a 45 ACP or a 455. I understand about the chamber length for a 45 ACP, but cannot see why anyone would shoot the gun without a clip? I would also not want to unload the brass one case at a time, hoping none are stuck.