- Location
- BC. Canada
Please delete --Hi, i am new to this 303 Rifle, I hear You talk about Head space , just what is "Head space " how do i measure it ? Thanks Please remove
Last edited:
Head space?
- Thread starter helmutbose
- Start date
guages or gunsmith
Howdy, you need to buy the gauges (ie. Forester) or take it to a gunsmith. That's about it in a nutshell.
That being said, I used some plastigauge with my M14. It was able to estimate enough to give me the knowledge that the headspace in my new M14 was "ok". However, the panic in some posts prompted me to buy some gauges. I got no worries now.
By the way, to accurately test, you have to remove the extractor pin (M14). I needed to headspace my 7600 pump, and chose instead to take it to a gunsmith. I also set up a "gauge" (so to speak) to measure the difference between fired casings and new casings from the perspective of shoulder distances. That method was within .001" of the gauge result.
Also took them to a Hungry clinic and they measured identical to gauges and was given satisfaction that everything was good to go, unless I wanted to competition shoot. Life is good now.
Howdy, you need to buy the gauges (ie. Forester) or take it to a gunsmith. That's about it in a nutshell.
That being said, I used some plastigauge with my M14. It was able to estimate enough to give me the knowledge that the headspace in my new M14 was "ok". However, the panic in some posts prompted me to buy some gauges. I got no worries now.
By the way, to accurately test, you have to remove the extractor pin (M14). I needed to headspace my 7600 pump, and chose instead to take it to a gunsmith. I also set up a "gauge" (so to speak) to measure the difference between fired casings and new casings from the perspective of shoulder distances. That method was within .001" of the gauge result.
Also took them to a Hungry clinic and they measured identical to gauges and was given satisfaction that everything was good to go, unless I wanted to competition shoot. Life is good now.
There is a gap between the boltface and the breechface of the barrel.
This is the space where the rim of the cartridge sits.
There are tolerances for the thickness of the rim, and the size of this gap.
Ideally, the gap between the boltface and the breechface should be .064" to .068". The military would allow a rifle with a gap of less than .074" to remain in service.
The rim is nominally about .060 thick.
Headspace is tested with gauges, Go (.064), No Go (.068), and Field (.074).
Using gauges is not exactly the same as actually measuring the gap between the two faces. This would produce an exact measurement.
Headspace gauges test for a Pass - Fail situation.
Easiest, fastest way to check your rifle is with gauges. Most any gunsmith in Canada is going to have .303 gauges.
You can get a rather accurate measurement of the gap between the faces using an unfired cartridge case, shimstock and a good micrometer. Once this measurement is established, you will have a pretty good idea what the situation is with respect to headspace in the rifle.
This is the space where the rim of the cartridge sits.
There are tolerances for the thickness of the rim, and the size of this gap.
Ideally, the gap between the boltface and the breechface should be .064" to .068". The military would allow a rifle with a gap of less than .074" to remain in service.
The rim is nominally about .060 thick.
Headspace is tested with gauges, Go (.064), No Go (.068), and Field (.074).
Using gauges is not exactly the same as actually measuring the gap between the two faces. This would produce an exact measurement.
Headspace gauges test for a Pass - Fail situation.
Easiest, fastest way to check your rifle is with gauges. Most any gunsmith in Canada is going to have .303 gauges.
You can get a rather accurate measurement of the gap between the faces using an unfired cartridge case, shimstock and a good micrometer. Once this measurement is established, you will have a pretty good idea what the situation is with respect to headspace in the rifle.
Technically this is true of any measurement but is a bit misleading. A gauge tests for a particular measurement. Depending on how accurate your gauges are, that P/F can constitute a measurement. In the case of military gauges, the GO gauge tells you that your headspace is greater than or equal to 0.064, and so on. In the case of a full set of headspace gauges, they are graduated in increments of 0.001 so you can tell the headspace to within a thousandth by finding the largest that will allow the bolt to close (ie P/F within a thousandth of an inch).
I have never seen or heard of a set of graduated gauges for .303 British. Doesn't mean they don't exist, or could not be made, but the likelihood of encountering a 'smith with such a set is low.
Not uncommon though, to have graduated sets for rimless cartridges used for target shooting, like .308.
That is why I suggested an improvised way of determining the actual size of the gap between the bolt and barrel faces.
Not uncommon though, to have graduated sets for rimless cartridges used for target shooting, like .308.
That is why I suggested an improvised way of determining the actual size of the gap between the bolt and barrel faces.
