What affects the headspace? Is it the number of rounds expended. I just got confirmation of my PAL and was going to take my dad's no4 out to the range. It was FTR'd in 51 and used as a hunting rifle . It hasn't seen a round since the 70's so I would hazard a guess that a hundred rounds or so have been through it. 3 or 4 at deer the rest at targets. Should I have it checked?
No4 mk1/2 headspace
- Thread starter alaus24
- Start date
stencollector
CGN Ultra frequent flyer
- Location
- shilo MB, the armpit of Canada
If you know someone with gages, it only takes a minute to check.
You can also look at your fired brass and get a general feel for how the headspacing is.
There is nothing to say that the headspace wasn't out the whole time your dad had the rifle. If the bolt number does not match the gun, that is also a warning that things may not be OK. Often, sellers would mix up bolts on resale, leaving the possibility that the headspace would not be within specs.
On a no4mk1/2, the headspace is adjusted by replacing the bolt head. There will be a small number along the edge. These normally run from 0 to 3, with 3 being the largest. A new gun normally had a 0 or a 1. There are also 00 and 4s, but these are rare.
You can also look at your fired brass and get a general feel for how the headspacing is.
There is nothing to say that the headspace wasn't out the whole time your dad had the rifle. If the bolt number does not match the gun, that is also a warning that things may not be OK. Often, sellers would mix up bolts on resale, leaving the possibility that the headspace would not be within specs.
On a no4mk1/2, the headspace is adjusted by replacing the bolt head. There will be a small number along the edge. These normally run from 0 to 3, with 3 being the largest. A new gun normally had a 0 or a 1. There are also 00 and 4s, but these are rare.
I'd add to sten's excellent info: Headspace is less of an issue if you don't reload ammo (passing on the info I received). But best is, find someone with gauges (gunsmith very likely) and that way you'll know for sure what you have.
Lou
Lou
- Location
- WMU248 near Edmonton
as sten collector noted, bolt heads are getting hard to find, 0 and 1 no problems 2 and 3 good luck and the elusive 00 and 4 well I've never seen one and other experts are not convinced that they even exist. 
Off the top of my head the no go gauge has a rim thickness of .074" and the military no go is .078" minimum go would be .068" as that is the rim thickness.
BUT don't quote me on those head space numbers as I said off the top of my head and me relying on memory is not always that good.
Off the top of my head the no go gauge has a rim thickness of .074" and the military no go is .078" minimum go would be .068" as that is the rim thickness.
BUT don't quote me on those head space numbers as I said off the top of my head and me relying on memory is not always that good.
stencollector
CGN Ultra frequent flyer
- Location
- shilo MB, the armpit of Canada
as sten collector noted, bolt heads are getting hard to find, 0 and 1 no problems 2 and 3 good luck and the elusive 00 and 4 well I've never seen one and other experts are not convinced that they even exist.
I just saw a 00 a few weeks back in the collection of a longtime Enfield collector. Perhaps next time I am out his way I shall bring my digital calipers.
For collectors of .303 Enfields, check in the "Technical Articles for Milsurp Collectors and Re-loaders"http://www.milsurps.com/forumdisplay.php?f=25 area.
It contains a very good article with animations from Parashooter........
Headspace 101 for .303's (click here)http://www.milsurps.com/showthread.php?t=10
Regards,
Badger
It contains a very good article with animations from Parashooter........
Headspace 101 for .303's (click here)http://www.milsurps.com/showthread.php?t=10
Regards,
Badger
"...What affects the headspace?..." Partly the amount of shooting, but mostly it's somebody changing the bolt head or assembling the rifle out of a parts bin without bothering to check the headspace.
Definitely check the headspace and be thankful it's a No. 4. No. 1's have no numbers on the bolt head to provide a bit of guidance. With them it takes a handful of bolt heads(at $20 each from Marstar), guages and trial and error until you find one that works.
"...headspace is adjusted by replacing the bolt head..." And checking the headspace with proper guages. Just going up one number gives no guarantee that that will fix bad headspace.
"...less of an issue if you don't reload ammo..." Nope. The ammo has nothing to do with it. Headspace is a manufacturing tolerance only. No amount of mucking about with a .303 case will fix bad headspace. It headspaces on the rim.
Definitely check the headspace and be thankful it's a No. 4. No. 1's have no numbers on the bolt head to provide a bit of guidance. With them it takes a handful of bolt heads(at $20 each from Marstar), guages and trial and error until you find one that works.
"...headspace is adjusted by replacing the bolt head..." And checking the headspace with proper guages. Just going up one number gives no guarantee that that will fix bad headspace.
"...less of an issue if you don't reload ammo..." Nope. The ammo has nothing to do with it. Headspace is a manufacturing tolerance only. No amount of mucking about with a .303 case will fix bad headspace. It headspaces on the rim.
The whole point of the post (which I should have stated ) I was unsure if it was safe to fire without checking. The bolt handle matches the action and mag serial no's. I just didn't want to fire it and injure myself or others. I will be buying new ammunition. So I will try it out and see how it looks. What should I be on the lookout for if the headspace IS off? thanks
It's highly unlikely that the headspace is a problem, especially so if the bolt and receiver numbers match. Shoot and enjoy, check it some time if you are near someone with headspace gauges but don't lose sleep over it.
- Location
- WMU248 near Edmonton
I've got a 0 in my bin that is much shorter then spec as well, but its not marked 00 so I'm assuming that its just been stoned down a lot.
