Headspace Guage for No. 4 Mk 1

[Son]

Brian

In the Canadian manual the .070 gauge is listed as “Base Maximum”, does this mean when the Enfield was brought back for inspection or repairs the head space was readjusted to .070 or less.

I'm asking because I was guessing that the head space was closed up due to the use of commercial ammunition by the Rangers????

Does anyone know the “official” reason for the three head space gauges the Canadian military used on the Enfield Rifle. (I gots to know)

Dunno about the Canuckian system, but I'd imagine it would be roughly the same as some of our gear was/ is...

The Go guage is rarely bothered with in the outside world. If it is so tight it won't close on this it wouldn't have left the factory/ repair shop. (or somebody has mixed up some parts...)

If it closes on the max. guage, then it is sent back to base level repair. Untill it reaches this spec and fails a unit armourers test, it stays in use.

After failing headspace (074) it would be sent for Base Level (not our terminology) repair and brought back to closing on the Go guage (064) but not closing on the middle size- ("base maximum"- doesn't leave base if it fails .070) giving the rifle several thou of wear and tear before it fails the max size (074) again.

Information

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[Peter Laidler]

Ignore any reference to a .070" CHS gauge in respect of the No1 and No4 rifles. It doesn't exist.............. The .070" gauge was only ever issued/used for Base workshop repairs to the Vickers gun. That's not strictly correct but is for our purposes.

.064" GO. .074" NO go. And for the purposes of NO go, then it means that the bolt handle must be at least .050" from touching the body-side and when fired, the cocking piece must click into the 'half-cock' position

[Brian Dick]

I don't know about the rifles issued to the Canadian Rangers Ed. I don't see why there would be a different specification as they wouldn't be reloading for them as far as I know and rim thickness on a rifle that passes the .074 should have no bearing on performance. There were production runs of .303 ammo in Canada made for issue to them up into the 1990's. I'd guess it was to military specification. They probably acquired commercial ammo too.

I do understand your concern because of the fact you reload and are looking for maximum case life but the fact is that it was never a consideration with military forces. I learned from Peter years ago that the .067 was for the Vickers MMG.

[Surpmil]

Interestingly the current CF manual for the No4 does not list the "GO" gauge, only the "NO GO" of .0740"

The list includes,

Gauges, Plain, Plug, Cylindrical, NOT GO, 0.310", .0370" and .308" (3 items)
Gauge, Plug, Taper, Cylindrical, NOT GO .303" to .3242", (1 item)
Gauge, Firing Pin Protrusion No3 MkI
Gauge Inspector's, Plug, .303" Chamber
Gauge, Armourer's, Striker Protrusion, No4 MkI

That's the lot - could be a mistake in the manual of course.

[Edward Horton]

When all else fails read the manual (RTFM)

2002 No.4 (All Marks) .303 Rifle Parts Identification List (Page 93 or 3-23/3-24)

Gauge, Headspace, NOT GO. 0.070 in. gauging lg,
for rifles No 4 Mk 1 cal .303 W/oversized locking
shoulders.

Now someone explain oversized locking shoulders.