So I have an Ishapore No1 MKIII that I bought a while back and finally got around to checking the headspace on it and while it didn't fail it wasn't exactly good either. So my question is how would I go about bringing the headspace into a more acceptable tolerance seeing as unlike the no4 the No1's don't have the same bolt head system. Knowing that I did some research and have read that some people silver solder steel shim stock to the bolt face it get the headspace they desire. I have also read that the armourers would take a longer bolt head and using a stone or emery cloth would hone the face into tolerance. I'm just wondering which method would be best or are there others out there that would be better.
Improving headspace on an Enfield No1 MKIII
- Thread starter Lucite
- Start date
The Mk III bolts heads are not labelled according to size, so you have to measure then, or test them by trial and error. If you're lucky, you can find an older gunsmith that has several, and go from there. Its more work than you think - as you will likely have to adjust the firing pin protrusion.
FWIW - If you are neck sizing or partial resizing, you can achieve the same benefit without changing the bolt head.
FWIW - If you are neck sizing or partial resizing, you can achieve the same benefit without changing the bolt head.
What did you use to measure the headspace? Modern headspace guages and Military headspace guages differ as to dimensions. Headspace is a factor that is not really fully understood by a lot of people. As mentioned, if you reload you can neck size only for a MUCH longer case life, but if you full length resize all the time, you will be very lucky to get a half dozen loadings out of a case. Use SMELLIE's trick of a rubber hair band over the base on the first firing to keep the case back against the bolt head. These small rubber bands can be bought at a "Dollar" store by the bag full.
However "headspace" is useful if you want to add another post number to your total. You can reply "Check the headspace" whenever someone gets a new rifle.
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However "headspace" is useful if you want to add another post number to your total. You can reply "Check the headspace" whenever someone gets a new rifle.
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Lucite
If you can find a new bolt head marked (S) for spare they were the longest bolt heads and were lapped to the correct length.
If your existing bolt head does not over rotate and is in good shape I would leave it alone, minimum headspace is .064 and maximum is .074.
Below No.1 and No.4 bolt head over rotation.
I'm not sure who or where "SMELLIE's trick of a rubber hair band" came into this because it started out by using a rubber o-ring. The reason for this is to hold the case against the bolt face "AND" when the o-ring is compressed and flattens it centers the rear of the case in the chamber and improves accuracy. If the rubber hair band has square sides it can force the rear of the case off center with the chamber.
After fire forming with a rubber o-ring the case is neck sized only and will headspace on the shoulder and not the rim and last much longer when reloading.
If you can find a new bolt head marked (S) for spare they were the longest bolt heads and were lapped to the correct length.
If your existing bolt head does not over rotate and is in good shape I would leave it alone, minimum headspace is .064 and maximum is .074.
Below No.1 and No.4 bolt head over rotation.
I'm not sure who or where "SMELLIE's trick of a rubber hair band" came into this because it started out by using a rubber o-ring. The reason for this is to hold the case against the bolt face "AND" when the o-ring is compressed and flattens it centers the rear of the case in the chamber and improves accuracy. If the rubber hair band has square sides it can force the rear of the case off center with the chamber.
After fire forming with a rubber o-ring the case is neck sized only and will headspace on the shoulder and not the rim and last much longer when reloading.
I learned about the rubber o-ring trick from a Canadian by the screen name of Terryinvictoria and after trying it I kept passing the word around.
And now the o-ring has mutated into pony tail rubber bands and you people are still not getting it.
The majority of commercial .303 brass is undersized at the base an it will just lay in the bottom of the chamber and when fired will expand on one side of the case more because of being off center in the chamber.
When you use a round rubber o-ring and compress and flatten it when the bolt closes, the compressed o-ring "centers" the rear of the case in the chamber. This promotes equal case expansion and increases your accuracy when the cases are reloaded.
Before I started using the rubber o-ring I used the false shoulder method by expanding the necks to .35 caliber and then necking down to .303. This created a false shoulder on the case and the case then headspace on the shoulder and not the rim. There were two problems with this method, 1. It was hard on case necks and caused premature split necks and 2. the rear of the case was not centered in the rear of the chamber.
So one more time, a "round" rubber o-ring will center the case and a "square" pony tail rubber band will not. If you are going to take the trouble to fire form the case why don't you do it the right way.
And now the o-ring has mutated into pony tail rubber bands and you people are still not getting it.
The majority of commercial .303 brass is undersized at the base an it will just lay in the bottom of the chamber and when fired will expand on one side of the case more because of being off center in the chamber.
When you use a round rubber o-ring and compress and flatten it when the bolt closes, the compressed o-ring "centers" the rear of the case in the chamber. This promotes equal case expansion and increases your accuracy when the cases are reloaded.
Before I started using the rubber o-ring I used the false shoulder method by expanding the necks to .35 caliber and then necking down to .303. This created a false shoulder on the case and the case then headspace on the shoulder and not the rim. There were two problems with this method, 1. It was hard on case necks and caused premature split necks and 2. the rear of the case was not centered in the rear of the chamber.
So one more time, a "round" rubber o-ring will center the case and a "square" pony tail rubber band will not. If you are going to take the trouble to fire form the case why don't you do it the right way.
You do not just screw another longer bolt head on your bolt and call it finished.
1. You have bolt head over rotation, and you pick a bolt head that is tight enough that it does not line up with the long locking lug. Then the bolt head is worked back and forth until the bolt head aligns with the long locking lug. If this is not done after firing a few rounds the newly fitted bolt head may have excess over rotation.
2. Bolt head timing, this is where the rear of the bolt head contacts the collar on the firing pin. This controls how far the cocking piece moves to the rear when the action is cocked and firing pin protrusion. If your looking from the rear of the bolt the long locking lug is held in the 12 O'clock position, as you screw in the bolt head it should contact the collar of the firing pin at the 3 O'clock position and only rotate 90 more degrees before coming to a stop and the bolt and bolt head making hard contact and not over rotating.
Above is the "proper British" way of fitting a bolt head when the Enfields were in use. The Canadian No.4 manual is written in such a way to keep the No.4 Enfield rifles use by the Canadian Rangers and the requirments have been loosened and you are given a minimum and maximum distance the cocking piece is to be pushed to the rear. You measure this as the distance from the rear of the bolt to the front of the cocking piece. This equates in bolt head timing to the rear of the bolt head contacting the firing pin collar anywhere between the 5 O'clock position to the 2 O'clock position. And making sure the firing pin protrusion is .040 to .050.
This is why I stated earlier if the bolt head doesn't over rotate and the headspace is not over the maximum of .074 then leave it alone and fire form your cases. This is because you need a very large assortment of bolt heads to find the "sweet spot" due to variations in the threads of the bolt and bolt head and aligning with the long locking lug on the bolt.
A New Zealander sent the photo below to me taken at his gunsmiths shop and joking said "eat your heart out Ed" knowing that the Enfield rifle was a stranger in a strange land here in the US and we never see anything like it.
Below a bolt head spanner was used to fit tight bolt heads by working the two mating surfaces together and "fitting" the bolt head.
NOTE: The very first bolt head I fitted was not tight enough, meaning it didn't over rotate with just finger pressure and I thought this would be OK. I fired 50 rounds and the bolt head over rotated and learned my lesson.
1. You have bolt head over rotation, and you pick a bolt head that is tight enough that it does not line up with the long locking lug. Then the bolt head is worked back and forth until the bolt head aligns with the long locking lug. If this is not done after firing a few rounds the newly fitted bolt head may have excess over rotation.
2. Bolt head timing, this is where the rear of the bolt head contacts the collar on the firing pin. This controls how far the cocking piece moves to the rear when the action is cocked and firing pin protrusion. If your looking from the rear of the bolt the long locking lug is held in the 12 O'clock position, as you screw in the bolt head it should contact the collar of the firing pin at the 3 O'clock position and only rotate 90 more degrees before coming to a stop and the bolt and bolt head making hard contact and not over rotating.
Above is the "proper British" way of fitting a bolt head when the Enfields were in use. The Canadian No.4 manual is written in such a way to keep the No.4 Enfield rifles use by the Canadian Rangers and the requirments have been loosened and you are given a minimum and maximum distance the cocking piece is to be pushed to the rear. You measure this as the distance from the rear of the bolt to the front of the cocking piece. This equates in bolt head timing to the rear of the bolt head contacting the firing pin collar anywhere between the 5 O'clock position to the 2 O'clock position. And making sure the firing pin protrusion is .040 to .050.
This is why I stated earlier if the bolt head doesn't over rotate and the headspace is not over the maximum of .074 then leave it alone and fire form your cases. This is because you need a very large assortment of bolt heads to find the "sweet spot" due to variations in the threads of the bolt and bolt head and aligning with the long locking lug on the bolt.
A New Zealander sent the photo below to me taken at his gunsmiths shop and joking said "eat your heart out Ed" knowing that the Enfield rifle was a stranger in a strange land here in the US and we never see anything like it.
Below a bolt head spanner was used to fit tight bolt heads by working the two mating surfaces together and "fitting" the bolt head.
NOTE: The very first bolt head I fitted was not tight enough, meaning it didn't over rotate with just finger pressure and I thought this would be OK. I fired 50 rounds and the bolt head over rotated and learned my lesson.
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Yup, I stole it from Ed, called it "Ed's O-rings".
Ed then told me that it wasn't his trick to start with.
I modded it to use pony-tail ties from the Dollar Store because they are 5 for a penny and the machine-shop wants half a buck for an O-ring.
That was because I have Scots border-rustler ancestry (along with the Nixons, BTW) and we are CHEAP!
And it is STILL a darned good idea! It reduces your effective headspace to ZERO and you end up with brass which fits PERFECTLY.
Ed then told me that it wasn't his trick to start with.
I modded it to use pony-tail ties from the Dollar Store because they are 5 for a penny and the machine-shop wants half a buck for an O-ring.
That was because I have Scots border-rustler ancestry (along with the Nixons, BTW) and we are CHEAP!
And it is STILL a darned good idea! It reduces your effective headspace to ZERO and you end up with brass which fits PERFECTLY.
theeasterner
CGN frequent flyer
- Location
- Treasure Island
Anyone out there got a MkIII bolthead longer than .642 ? I need about .645 or more.
Shake Loose the Border!
Using O-rings to fire form a rimmed cartridge is an interesting idea, may have to try it in the future! ( you learn something new every day )...another method I have used with my #4 MK II was to seat my bullets so they made good hard contact with the rifling, this pushed the cartridge up againest the bolt face allowing the shoulder to move forward without any stretching in the area of the head of the cartridge. you should only do this with new brass and you need a bore that is in good shape with enough rifling left in the throat to make good contact with the bullet. When loading for fire forming you should use the starting load in the reloading manual with a powder like IMR 4895 to keep the pressure from being excessive due to the contact with the rifling. This technique can be found in most reloading manuals.
