Lee Enfield No. 4 MK I questions

[T. O'Heir]

"...a test fire..." That just test to see if the rifle will go bang. Nothing else.
"...It is not rocket science..." Needed to be bigger. snicker. You need a No-Go and a Field headspace gauge(that you can buy or rent with no fuss). No bits of tape, empty cases, gum, empty cases or anything else. Slip the No-Go gauge under the extractor and gently(no force at all) close the bolt. If the bolt does not close completely, the headspace is ok. However, if it does close, do the same thing with the Field gauge. Again, if the bolt does not close completely, you're fine. If it does close, the headspace is bad.
The CF(CDN Military) on the.303British page(Steve Redgwell.) didn't use Field gauges. That'd be the .74 gauge mentioned. If a rifle failed the check with a No-Go, it was taken out of service.
http://www.303british.com/id28.html
"...I am not an SMLE guy..." That'd be good. A No. 4 Lee-Enfield IS NOT an SMLE.

 

[emcon5]

Kind of a ghetto way to do it, but if you are a reloader, you can do a basic headspace measurement of a rimmed cartridge with an empty case and spent primer.

The advantage of this is you can get an actual measurement of your headspace, not just "somewhere between .064 to .074".

Put the spent primer barely in the primer pocket, just enough that is doesn't fall out, and chamber the round. Closing the bolt will press the primer deeper in the pocket, but there will still be a little protrusion.

Get your digital calipers, and measure the thickness of the rim, plus the protrusion of the primer and add them up. The result will be the headspace.

Do it a few times to make sure you get consistent results, as long as you are under .074" you are good to go.