My early (s/n 65030) Winchester M1917 came with a slightly worn but functioning Eddystone bolt and an extractor that is only stamped "CV" for chromium vanadium steel. I recently purchased a W stamped bolt and later found a W stamped extractor that is identical to the CV stamped extractor except it has a gas hole drilled near the claw. The W extractor is unworn and works perfectly. When or where was a W stamped gas vented extractor used? On early M1917s or P14s?