Thanks for your help. Full story: I bought the NOS Winchester bolt to replace a slightly worn Eddystone bolt that was originally installed on my M1917 Winchester rifle when I bought it. The E bolt would close on a gunsmith’s no go gauge but only closes about 80% on my field gauge. The W bolt closes about 50% on the same field gauge. Seeing the difference in closing percentage makes me think that the W bolt would probably not close on the gunsmith’s gauge.

I’ve not fired the rifle with the W bolt but I was able to successfully chamber and eject a dummy .30-06 round smoothly and it fits nicely inside the chamber with minimal movement.

The field gauge measurements on the E and W bolts were taken with the strikers removed.

Because I thought the E bolt was worn, I’ve been watching the internet all this time for a NOS W bolt, although the E bolt has successfully sent hundreds of bullets down range over the 4 years that I’ve owned the rifle without inflicting any damage to the rifle or the brass cases. In fact, I’m still reloading the original cases. I’ve had zero case-head separation and only one case that became unusable due to an enlarged primer hole. I re-sized the case and pressed in a bullet anyway and use it as my .30-06 dummy round.

I’d be interested to hear the story about the long chambers.