BNP under crown = British Nitro Proof
Standard commercial export proof mark.
ENGLAND was stamped on arms supplied to foreign countries, and an upward pointing broad arrow mark is a govt. acceptance mark.
The important markings are on the left flat of the receiver. For instance my No. 5 has the following:
No5MK1 ROF (F)
2/45 G35XX
This indicates that the rifle was manufactured at ROF Fazakerley in February 1945, with a serial of G35XX (I x'ed out the last two).
No. 5s were produced only in England at Fazakerley, and B.S.A. Shirley between 1944 and 1947. Less then 300,000 No.5s were manufactured in total.
The bolt handle should have a matching serial. If you are lucky, the forearm, and magazine will too.
If the markings indicate a No4 rifle, then it was privately converted for the commercial market.
Until a couple of years ago No. 5s were fairly scarce. This has changed since Century imported a bunch from Indonesia recently.
I am not a ballistics guy, so I can't answer your other question. I just shoot 'em.
Now... Does anyone have an excellent condition Wilkinson No.5 MK 1 bayonet to sell me?
Cheers,
Chris
P.S. DScottHewitt,
My Skennerton book indicates that 100 No.5 MK2 rifles were manufactured by BSA Shirley. I'd sure like one of those.