Going price on M1917?

[lyman]

enfields are rimmed, so a different style of headspace gauge applies,

the 1903 and A3, as well as the 1917 headspace using the same gauge, but again, not really as meaningful as the throat measurement (headspace is cartridge length to a datum point, throat measures the barrel erosion,,,)

and no, if you are using USGI 30.06 gauges, you do not have to remove the firing pin, the gauges are relieved for them,

[RC20]

The difference in the 1903/A3 and the 1917 is the 1917 is a cock on close. It has a very powerful cam action in the close part (vs the extraction). I think Hatcher wrote that up.

Ergo, yes you do want to remove the striker, its not interference, you can't feel the tightness of the gauge with it in, if you close it you can strain things and damage the gauge.

the 1903 and A3, as well as the 1917 head-space using the same gauge, but again, not really as meaningful as the throat measurement (head-space is cartridge length to a datum point, throat measures the barrel erosion,,,)

As noted, 303 SMLE is a different critter, head space was set with 4 different bolt-heads if I am remembering that right (just familair not a lot on those)

1903/1917/1903A3 and head space in general is a bit different. The Military had their own head space gauges as SAMI did not exist. I assume they just took the spec from the military, keeping in mind military chambers can and do what they want (5.56 vs 223, shoot 223 in 5.56 but not reverse) - the muck of combat means they don't want tight.

So, the gauges we mostly have access to are No Go, Go (Field gauges a bit less common and have to buy those separately normally, the Go /No Go oven come as a set.

A NO go is ok, its just pretty tight, some ammo may not fit if its not sub spec a tad. Reality is it just means you can set to No Go, but anything less will require a serious squish down of the brass if you reload and not fired in that gun.

Go is just that, kind of optimal but anything between a No Go and a Go is fine as well (tad iffy but almost certainly ok) Go is going to be for sure 100% ok with any ammo.

Then there is Field Reject. Having worked with Savages and barrels on and off, I have found its not the critical issue it made out to be (not to be casual either)

What it does mean is brass won't last long (unless you size it to the chamber). On a 1917 if you reload, you will want to segregate the brass because you will have to set it back a fair amount (and that cracks the base after 2-8 rounds). The 303 Mil Surplus guns will often be good for only two loading as the chamber is generous (I think large as well as long)

What Field Reject (often just Field) is to the military is we need to set that barrel back a bit more.

I have had a couple of cases where I got it too long and it simply would not fire the round.

Other cases the extractor will hold the round tight enough to fire it.

A really bad out past field reject someplace will rupture a case.

For 30-06
Go : ............. 2.049
No Go: ............ 2.055
Field Reject:...... 2.058

You can create a Field Reject form a Not go by putting a piece of masking tape on the back.

The 1917 tends to almost Field Reject

The 1903/A3 tends more to No Go.

Why I have not a clue, you would think both would match pretty close with accepted mfg variation of the day.

[lyman]

USGI 30.06 are

1.940 go
1.946 no go
1.950, field

from what I have read, just a different datum point measurement,

I have a set of each (USGI and Saami, ) and the measure the same when I use them on the same gun

[RC20]

I can see that, really make no difference on the shoulder where you do it, its consistent.

Interesting to see done differently, civie gauges would be to SAMI of course.