168bergersapper
Regular
- Location
- Vancouver Island
Can anyone explain to me the difference in bolt head sizes and when or why they were used? Thanks in advance.
Lee enfield bolt head sizes?
- Thread starter 168bergersapper
- Start date
168bergersapper
Regular
- Location
- Vancouver Island
So would "0" be the shortest and therefore what they started from the factory with or vice versa?
- Location
- WMU247 near Edmonton
each number is slightly larger then the last, and if you need one bigger then a 3 then it is likely that you need a new bolt.
I see your in Edmonton and I'm guessing that your a sapper.
I may be able to help you out with your enfield problems.
I see your in Edmonton and I'm guessing that your a sapper.
I may be able to help you out with your enfield problems.
0 is the shortest, but they would have left the factory with whatever made that bolt work in that rifle. they made bolts and dumped them in a box, and somewhere else the receiver and barrel were made and chambered etc then someone sat with bolts and bolt heads and a gauge to get them all fitted. after that an oiled round was fired to set the lugs properly, and headspace checked again. then they would be numbered together and set to kill the hun
the earlier SMLE bolt heads were fitted to the rifle in the same way, but an oversized bolt head was stone ground to fit the rifle rather than just pulling numbers
- Location
- Western Manitoba
And just to be clear - like any other rimmed or belted cartridge case original design, the "headspace" being addressed was the room for the cartridge rim between the bolt face and the breech face - in a 303 British, the "headspace" being established by swapping out bolt heads has nothing to do with length from bolt face to cartridge shoulder or any point on it. Apparently, especially the SMLE had a "longish" chamber to ensure dirty, rusty and sub-standard condition cartridges would load and fire, so no consideration was ever given to case life that we hand-loaders 100 years later may be concerned about
- Location
- campbell river bc
At one time, I used to check the headspace on Lee Enfields by placing various sizes of shim stock between the bolt face and the base of a .303 British case in the chamber. Depending on the thickness required to make the bolt face fit tight to the chambered shell, I used to silver solder a piece of stainless shim stock to the face of the bolt, usually about 1 or 2 thousands thinner and corrected headspace in this manner. A lot of people used to "poo poo" my so called fix for excessive headspace but I never had a single problem and some of these guns were fired a lot after I did this work. Also allowed better accuracy and sometimes improved magazine feeding. I would be interested in hearing what knowledgeable gunsmiths thought of this idea. Thanks in advance. Jack
Years ago I used to have a collection of at least a dozen or so many LE No.4 bolt heads and one day when I had nothing better to do I got my digital caliper out and was surprised to find that some of my #0 ones were longer that some of my #1 ones and one of my #0 was very slightly longer than a #2 one and I even had a #3 that was the same length as a #1 I had.
Also what was confusing was that very few in any number range was the exact same length as others in that number range but some were the same length as one in the next numbered range.
After that I sorted and stored them in a container tray with individual bins by actual measured size and not stamped numbers. I used them to make sure every Lee Enfield I had had nice tight headspace. And more than once I ended up fixing loose headspace by changing out a LE bolt head with a higher number to a lower numbered but actual longer and tighter bolt head to get tighter headspace on a rifle.
It looked to me that the many different makers of these bolt heads didn't have a standard sizing range that they all followed together and it could be that they made them in batches to a rough average size range with no strict size regime or rule and probably just numbered them as a sort of guide only but confirmed and fitted the correct bolt head needed with headspace gauges when making/repairing or servicing these rifles.
Also what was confusing was that very few in any number range was the exact same length as others in that number range but some were the same length as one in the next numbered range.
After that I sorted and stored them in a container tray with individual bins by actual measured size and not stamped numbers. I used them to make sure every Lee Enfield I had had nice tight headspace. And more than once I ended up fixing loose headspace by changing out a LE bolt head with a higher number to a lower numbered but actual longer and tighter bolt head to get tighter headspace on a rifle.
It looked to me that the many different makers of these bolt heads didn't have a standard sizing range that they all followed together and it could be that they made them in batches to a rough average size range with no strict size regime or rule and probably just numbered them as a sort of guide only but confirmed and fitted the correct bolt head needed with headspace gauges when making/repairing or servicing these rifles.
New bolt head sizes were to fall into the follow lengths.
0 - .620 to .625 in.
1 - .625 to .630 in.
2 - .630 to .635 in.
3 - .635 to .640 in.
At the top of milsurp page is a sticky "Lee Enfield On-line Knowledge Libraries (Index of Articles)" with all the Enfield information you could possibly need.
Below are the 1991 Canadian No.4 Enfield manuals, they are written to keep your Enfield rifles serviceable and are easy to understand.
1991 No.4 (All Marks) .303 Rifle Manuals (Complete Set)
http://www.milsurps.com/content.php?r=335-1991-No.4-%28All-Marks%29-.303-Rifle-Manuals-%28Complete-Set%29
Military headspace is .064 minimum and .074 maximum, your Canadian manual tells you to select the smallest bolt head that will not close on the .074 headspace gauge. What is important is bolt head over rotation, (see manual below) than having tighter headspace. Even at the longest headspace of .074 all you need to do is fire form your cases and let them headspace on the shoulder and not the rim. And then only neck size your cases for longer case life.
1991 No.4 (All Marks) .303 Rifle Maintenance Instructions
http://photos.imageevent.com/badgerdog/generalstorage/edhortonmanuals/No4Mk1Arm.pdf
Because of the age and lack of spare parts the Canadian manual is more lenient than the original "Instructions for Armours" and a must have manual for any Enfield owner. Now all you people have to do is read all the free information in the "Lee Enfield On-line Knowledge Libraries".
NOTE: If your are measuring used bolt heads the numbers mean nothing, and when new the bolt head numbers were to fall into the range printed above.
With use the bolt head and bolt became shorter, and why new bolt were fitted to bring the rifle back into headspace limits. If a new bolt and #3 bolt head were fitted and the rifle failed the .074 gauge the receiver lug recesses were worn beyond use and the reciever was scrapped and the rifle parted out.
0 - .620 to .625 in.
1 - .625 to .630 in.
2 - .630 to .635 in.
3 - .635 to .640 in.
At the top of milsurp page is a sticky "Lee Enfield On-line Knowledge Libraries (Index of Articles)" with all the Enfield information you could possibly need.
Below are the 1991 Canadian No.4 Enfield manuals, they are written to keep your Enfield rifles serviceable and are easy to understand.
1991 No.4 (All Marks) .303 Rifle Manuals (Complete Set)
http://www.milsurps.com/content.php?r=335-1991-No.4-%28All-Marks%29-.303-Rifle-Manuals-%28Complete-Set%29
Military headspace is .064 minimum and .074 maximum, your Canadian manual tells you to select the smallest bolt head that will not close on the .074 headspace gauge. What is important is bolt head over rotation, (see manual below) than having tighter headspace. Even at the longest headspace of .074 all you need to do is fire form your cases and let them headspace on the shoulder and not the rim. And then only neck size your cases for longer case life.
1991 No.4 (All Marks) .303 Rifle Maintenance Instructions
http://photos.imageevent.com/badgerdog/generalstorage/edhortonmanuals/No4Mk1Arm.pdf
Because of the age and lack of spare parts the Canadian manual is more lenient than the original "Instructions for Armours" and a must have manual for any Enfield owner. Now all you people have to do is read all the free information in the "Lee Enfield On-line Knowledge Libraries".
NOTE: If your are measuring used bolt heads the numbers mean nothing, and when new the bolt head numbers were to fall into the range printed above.
With use the bolt head and bolt became shorter, and why new bolt were fitted to bring the rifle back into headspace limits. If a new bolt and #3 bolt head were fitted and the rifle failed the .074 gauge the receiver lug recesses were worn beyond use and the reciever was scrapped and the rifle parted out.
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Most if not all the size difference between used and new bolt heads of the same number is in the threaded section of the bolt as this is the part that would compress or setback the most, I never bothered to measure this part of the bolt head.
I have also seen and measured lots of bolt bodies from the back of the rear locking lug to the front of the bolt without a head installed and found none seem the same in length (some much longer than others). It was common for the bolt bodies and bolt locking lug to compress slightly with use also, not just the bolt head threads which would pretty much stop compressing when the back of the bolt head butted up flush with the bolt body mouth.
The military EME armorer techs would also often recycle bolt bodies by grinding off the old serial number and reusing them on other rifles then re-stamp the matching serial number of the rifle.
I have seen many Lee Enfields that have been re-barreled many times with little or no receiver lug recesses that were worn out (maybe some set back, but more often flattened bolt lugs) and never seen one that needed scraping because of it (not saying it does not happen). If a longer bolt body and head could not fix excessive head space, just removing a turn off the barrel and rechambering it would.
I also found this chart from another website forum that measured 220 No.4 bolt heads that seems to match my experiences with LE bolt head sizes -
As can be seen some are way outside of their respective size range by bolt head number (especially longer ones) that can not be taken as a case of compression from use.
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168bergersapper
Regular
- Location
- Vancouver Island
Excellent,thank you for the responses.
This is incorrect and why bolt head over rotation is so important, when the bolt head over rotates past 20 degrees the thread take the pounding which you do not want. The mating surface of the bolt head and bolt body are to be taking all the bolt thrust and these two mating surfaces take most of the wear.
What you were seeing was wear and not compression, with the majority of the wear at the front of the bolt where it mates with the bolt head. When the Enfield rifle was proof tested a oiled proof cartridge was used and after proofing if the headspace increased over .003 the rifle failed proof testing.
This is correct "IF" the bolt met minimum length from the rear of the bolt lugs to the front of the bolt body. And again if a new bolt and a #3 bolt head failed headspace testing the receiver was scrapped and the rifle parted out.
A Enfield sent for FTR could have the barrel replaced for many reasons, BUT when a new barrel was installed the rifle was proof tested again. If the bolt was hard to open it meant the surface hardening in the receiver lug recesses had worn through, and the receiver was scrapped. And I have never heard of the military taking a turn off the barrel, let alone using this method to fix a headspace problem. Problems like this were not fixed at base level and were sent to overhaul facilities at the highest level of repair.
The chart by Allen De Enfield is completely worthless, his chart is like going into a junkyard and measuring tread depth on old worn out tires and trying to figure out how much tread a brand new tired had.
Bolt heads and bolt bodies do not compress and get smaller, they become smaller from wear at the mating surfaces. If you rub your finger over the end of a worn bolt body at the mating surface of the bolt head, you will feel a sharp edge from it being peened from the bolt thrust of the bolt head.
Below 95% of all the Enfield books and manuals were donated by me at Milsurps and I also have the British FTR/overhaul specifications for the No.4 Enfield rifle. At one time I had the largest and only Enfield manual sticky anywhere on the internet. So I have printed backup for everything that I say in my postings, meaning the material came straight form theses manuals and are not internet rumors. If you have any doubt about what I have posted you can go to the Milsurps Enfield forum and ask Peter Laidler the senior armourer in the U.K. if it is correct.
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BigEd: Great info on an often misunderstood subject. I do think Alan deE's spreadsheet is useful as, shortening by wear not-withstanding, it clearly shows the overlap between sizes. Specifically look at the upper ranges observed for No 1 and 2 boltheads. One lesson I take from it is to not immediately run from a rifle that has a number 3 bolthead out of fear that the action body might be worn out. A recent rifle I bought has a No 3 bolthead that measures a mere 0.630inch front to rear (and the gun is within headspace requirements with that bolthead). Owners need to know that simply buying a single bolthead one size up from their current one is probably a waste of time. Far better to go to a pro who has a drawer full of boltheads who can find one that tightens headspace (if really necessary, of course) and has proper overturn and who can also then check firing pin protrusion, etc.
milsurpo
milsurpo
milsurpo
There is a lot more involved with fitting a bolt head than they understand, if the new bolt head is not a tight fit you could have bolt head over rotation after firing a box of cartridges. The next thing is called bolt head timing which is the point the rear of the bolt head contacts the collar on the firing pin.
Many of these topics and other were covered at Milsurps and its a great place for information. I'm not saying canadiangunnutz is lacking but at Milsurps you have Peter Laidler the senior British Armourer and Enfield author.
And Allen De Enfield was also called Allen De Pretentious because he was great at coping everything that other people said or wrote and posting it later. Again the chart he made is worthless and what he should have done was get the lengths of new unused bolt heads. Therefore the number size stamped on a "USED" bolt head means nothing, the length of the bolt head continues to get shorter from the time the rifle is proof tested and through its lifetime. Todays rifles are made of much harder steels and better heat treating and when properly cared for are less effected by the effects of bolt thrust.
The idea behind the Enfield rifles replaceable bolt heads was that the rifle could be kept in service longer with the steels used in it construction. When the No.4 came into service the steel and heat treating was upgraded but this did not change the effects of bolt thrust and increasing headspace on the rifle. One of the things that I found aggravating were people coming into forums and telling people to lube their cases to prevent the case from stretching. Below is from the 1929 British Textbook of Small Arms.
The British used the "Base Crusher" system of measuring chamber pressure, and a hollow copper crusher was used to allow the firing pin to pass through the copper crusher and hit the primer. When the case was oiled the rifle would measure total chamber pressure and if the case was dry it would give much lower readings. Meaning the dry cartridge case acted like a shock absorber and reduced bolt thrust. Bottom line, the Enfield receiver wears and the bolt and bolt head gets pounded shorter with use. The Australian emergency wartime headspace was .084 for their Enfield rifles or .010 greater than the .074 maximum headspace setting. And I have test fired one of my Enfield rifles at this setting and all that happened was the cases stretched more and were worthless for reloading.
There is a lot more involved with fitting a bolt head than they understand, if the new bolt head is not a tight fit you could have bolt head over rotation after firing a box of cartridges. The next thing is called bolt head timing which is the point the rear of the bolt head contacts the collar on the firing pin.
Many of these topics and other were covered at Milsurps and its a great place for information. I'm not saying canadiangunnutz is lacking but at Milsurps you have Peter Laidler the senior British Armourer and Enfield author.
And Allen De Enfield was also called Allen De Pretentious because he was great at coping everything that other people said or wrote and posting it later. Again the chart he made is worthless and what he should have done was get the lengths of new unused bolt heads. Therefore the number size stamped on a "USED" bolt head means nothing, the length of the bolt head continues to get shorter from the time the rifle is proof tested and through its lifetime. Todays rifles are made of much harder steels and better heat treating and when properly cared for are less effected by the effects of bolt thrust.
The idea behind the Enfield rifles replaceable bolt heads was that the rifle could be kept in service longer with the steels used in it construction. When the No.4 came into service the steel and heat treating was upgraded but this did not change the effects of bolt thrust and increasing headspace on the rifle. One of the things that I found aggravating were people coming into forums and telling people to lube their cases to prevent the case from stretching. Below is from the 1929 British Textbook of Small Arms.
The British used the "Base Crusher" system of measuring chamber pressure, and a hollow copper crusher was used to allow the firing pin to pass through the copper crusher and hit the primer. When the case was oiled the rifle would measure total chamber pressure and if the case was dry it would give much lower readings. Meaning the dry cartridge case acted like a shock absorber and reduced bolt thrust. Bottom line, the Enfield receiver wears and the bolt and bolt head gets pounded shorter with use. The Australian emergency wartime headspace was .084 for their Enfield rifles or .010 greater than the .074 maximum headspace setting. And I have test fired one of my Enfield rifles at this setting and all that happened was the cases stretched more and were worthless for reloading.
168bergersapper
Regular
- Location
- Vancouver Island
wow so much great info!!
I am restoring a long branch sporter with new wood and new manufacture replacement barrel. Would fitting this barrel to a new/old stock bolt head be advisable? Or just go with the no.2 bolt head currently on the bolt?
I am restoring a long branch sporter with new wood and new manufacture replacement barrel. Would fitting this barrel to a new/old stock bolt head be advisable? Or just go with the no.2 bolt head currently on the bolt?
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- Location
- WMU247 near Edmonton
I would sugest starting with a 0 or 1 bolt head.
If the existing bolt and bolt head are tight and do not over rotate and the new barrel falls within headspace limits I would leave it alone. When the rifle was proof tested with a oiled proof round this seated the lugs to the receiver and the bolt head to the bolt. On the very first bolt head I ever replaced after firing approximately 100 rounds I exceeded the 20 degree limit of bolt head over rotation. There was a special bolt head wrench used to fit the tight bolt heads so the bolt head could be worked back and forth until the bolt head aligned with the right locking lug. Meaning using just your fingers the bolt head should stop moving before aligning with the bolt locking lug. And then be fitted by working it back and forth until it aligns with the locking lug. This insures maximum contact between the two mating surfaces and more surface area to absorb bolt thrust.
Bottom line, the average person does not have hundreds of bolt heads to choose from and bolt head over rotation is more important than meeting SAAMI .064 to .067 civilian headspace limits. The Canadian No.4 manual tells you if the rifle fails headspace testing to choose the next longest bolt head that will not close on the .074 gauge. Meaning as long as the bolt did not close on the .074 gauge the headspace was good to go and they didn't need to set it as close to the minimum .064 as possible.
If you look at a SAAMI chamber drawing for a civilian rifle the headspace is listed as minimum and maximum with .010 in between the two. And the GO and NO-GO gauges are used for setting up a new barrel and the distance between the two gauges is .003 which leaves you .007 wear before you exceed maximum headspace. Your Enfields min and max .064 to .074 headspace isn't the problem, the problem is getting good cases like Prvi Partzan and not over resize your cases when using full length dies.
By neck sizing only and using Prvi cases I have gotten over 32 reloading from these cases and they die of split necks. The secret is to not over stress the brass and not push it beyond it's elastic limits and to remember your not reloading for a magnum rifle.
