Trying to Identify Origin of a 1911 Barrel

I have what I believe to be a barrel for a 1911-type pistol. I have attached photos of the barrel and proofmarks on it. There appears to be one or more words below the proofmarks, but I cannot read what it says. The only other markings are a P on one barrel lug and an F on the other. (You can see the F in the photo of the proofmarks.) The specific type of ammunition for which it is chambered is not marked, but a .45 ACP round seems to chamber properly. The barrel appears to be blued, but it is a very dark finish. Can anyone identify the origin of this barrel? Is it likely chambered for .45 ACP? Thank you in advance.

USMA79

The script says "Not English Made(Make?)"...typical of ordnance that was LL to the UK. Probably .45 ACP unless it's .455?

Thank you. I think you've broken the code on the lettering on the barrel. I'll check with a local gunsmith -- I assume he'll be able to let me know whether the barrel is chambered for .45 ACP or .455 Webley Auto.

USMA79

All he needs is both cartridges, they you two slide them in a see what chambers correctly. There are guys here that would know if a .455 barrel would be marked as such...don't know where they are though.

Sounds like it could be a Flannery barrel that was installed in a M1911/M1911A1 that passed through an English proof house.

Thanks very much. After reading your note I looked at photos on some other websites. The markings on the barrel lugs definitely look like those on barrels manufactured by Flannery Bolt Company.

USMA79