There are other opportunities with these old beaters as well. I look for revolvers in the sub-$100 range that are within my meager abilities to repair, phosphate them at home on a Coleman stove, and then give them to someone as a way of introducing them to shooting. Works pretty good. They...
Sounds like you intend to reload for the old gun. Good. If you want to optimize your reloads then use a .45 Colt resizing die and use .45 acp dies for the belling, seating, & crimping operations. The .45 Colt and .455 cases are almost exactly the same diameter (and both are larger in diameter...
The .455 caliber designation on later HE2's is on the left side of the barrel but the earlier ones, including your serial number range, have no caliber markings at all.
Someone evidently attempted to provide .45 acp markings on yours to show it had been converted.
-Bob
I've owned a couple of commercial 1917's over the years. I can tell you that the commercial models are considered "scarce" when you buy them and dealers typically charge a premium as such.
When you go to sell them you will find that, while scarce, the commercial 1917's are not as "desirable"...
Here's the best recipe for accuracy in converted .455's that I know of. It has worked well for me in converted Colts and S&W revolvers. It works much better than just using standard .45 ACP dies, cases, & bullets.
Use dedicated cases. I use Starline .45 Auto Rim cases instead of moon clips...
They work fine in .45 ACP revolvers that have headspace shoulders. In those instances the Rimz clips are simply providing a surface for the extractor to bear on. If you have an early Colt 1917 without headspace shoulders, or a Webley Mk VI, Colt NS, or S&W HE2 that has been converted from .455...
I just bought an old .455 HE2 from HandEjector (as good and professional internet transaction as I've ever encountered, I might add. Thanks, Lee).
It's a bit tricky miking the chamber because it's not a nice right-angle transition from chamber to throat. It's more like a funnel or angled...