Early S.A M1

[Joe W]

In regards to the "BNP" mark on the receiver ring under the hump of the op-rod, the following is from an article by Scott Duff in the Apr. 2002 American Rifleman.
" In addition to the barrel proof marks, the Rules of Proof stated that both the receiver and bolt be marked. Birmingham used its BNP proof to mark the top of the receiver ring directly above the chamber; London used a crown over intertwined GP to mark the right side of the receiver ring under the hump of the op-rod. Both houses stamped the right lug of the bolt.
The proofing dies however, were no match for the hardened steel of the M1 Garands receiver and bolt and wore out in short order. Only a small fraction of Lend Lease rifles show these proofs or parts of them: most carry only a dent or smudge. Many show no evidence at all, suggesting that both houses eventually gave up the attempt."