LE No4 bolt head timing to bolt

I

I Dont Care About You

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Who knows something about how LE bolt heads are timed to the bolt?

I'd like to swap out bolt heads to try to tighten up headspace a bit. My rifle will currently just barely swallow the NoGo gauge. I have a longer bolt head but it tightens up on the bolt body before it aligns properly.

The machinist in me just says chuck bolt body up in the lathe and take a skim off the front edge to let the bolt turn far enough to properly align. But then I wonder if that would just make the bolt-head assembly too short again and produce overly generous headspace?

Or is it just a matter of swapping out parts combinations of bolts and heads till I find something that locks up properly and has the correct headspace?
 
Go to milsurp website and find articles by Peter Laidler in the Knowledge Library. What you are describing is "clocking" the bolt head to the bolt body - there was an allowable/permissible error when the bolt head was turned all the way tight to the bolt body - has to do with making sure that recoil is transferred from bolt head to bolt body, NOT through the threads. I believe during war-time that a field armourer who was going to replace the bolt head, usually had a plethora to pick through - trial and error - to get one that clocked within spec, and then also improved headspace.

FYI - "headspace" in rimmed 303 British is simply the clearance for the thickness of the rim - has about nothing to do with the chamber body shape, size or length. I had read that some headspace gauges that were available for 303 British looked like a dime - just a flat disc - was only to check that clearance for the rim thickness. But if you have verified that it will swallow a NOGO gauge, you probably know that. I believe the Lee Enfields, like the P14 and P17, had "helical breeching" - so the bolt continues to move forward until the handle hits it's stop - is the ONLY correct place to gauge headspace - at the bolt handle stop - not part way through the bolt handle movement, like many do with a Mauser ...
 
What NO GO gauge? .068? .074? SAAMI is the former.

Shortening the bolt sounds like a bad idea.
Better to try different bolt heads until you find a longer one that also indexes, if you wish to reduce the bolt face/breech face gap.
 
"shortening the bolt" or the "bolt head" - was apparently done, or perhaps variances in manufacture - apparently some Internet guy was miking many LE No. 4 bolt heads - he found many #2 that were shorter than #1, some #3 that were shorter than #2 - so is nothing guaranteed about the number stamped on the bolt head - likely want to actually measure it from rear shoulder to face, to know that your replacement is longer than the one that you are swapping out - as well as "clocking" within spec.

Go here - he measured 220 bolt heads - https://www.enfield-rifles.com/no4-no5-bolt-head-sizes-update_topic5019.html

Tiriaq's post #3 is very relevant - I think at different times that Britain, Canada and Australia may have had different standards that their militaries used, and likely all different than USA SAAMI - USA, so far as I know, never used any rifle that was chambered in 303 British for their military, but their SAAMI publishes a standard for it - not sure any of the world's militaries, that were in production 30 years before SAAMI existed, really cared ...
 
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I believe the bolt head should not over clock beyond 8* past the locking lug.

Also buy the bolt head by measurement as stated above the numbers doesn't mean it's longer or shorter
 
Too tight headspace could be armourer adjusted by stoning the bolt face to shorten the head. Assuming a shorter bolt head was not available. I suspect timing was accomplished by selective assembly. Going through the graduated series of bolt heads, sizes 0 through 3, each successive size was a specified amount longer, as originally manufactured.
If a bolt body were ever chucked up and faced off, the only bolt head that would ever fit would likely be the one fitted at the time of the machining. Bolt head threads are -14 pitch. The amount to bring a bolt head to index could be calculated. That would also be the amount the bolt length, locking surfaces to bolt face, would be shortened.
Only No. 4 bolt heads came in graduated sizes. Replacement SMLE heads were stoned to fit.
 
Gents. "clocking" the bolt head. Tight objective is 1/4 of the width of the rib past the start of the rib is the ideal. Any more is not good. That is the way the armourer trained me. Often one could not find the desired bolt head in the spares box. So if we could get very close then stoning the face of the bolt head was a common event although that took forever by hand. Headspace gauges were about 1 3/4 in long. A go gauge and a no-go. They not only did the headspace but also could catch a chamber burr which is rare. Generally if a bolt will close smoothly on a go gauge then you are good to go. I'm sure my gauges are copies but I do have an original .303 bore gauge with the C broad arrow and various ID marks etched on the handle extension so small and fine one needs a magnifying glass to read. It is possible that head space gauges may be the same but also the no-go gauge has an extra circumference cut so it could easily be identified. LB also made go and no-go gauges for the .22. These gauges were so small they easily rolled off the work bench and into obscurity. So high school shop made gauges were obtained because if you think that a real Canadian armourer was issued with all tools needed think again. JOHN
 
Thinking some more - I think minimum allowable was called "GO" gauge, and Maximum allowable was called "FIELD" gauge. The "NOGO" appears to be slightly longer than "GO" but much shorter than "FIELD" - so might be used when a "new" barrel is installed or chambered - is not apparently a regularly used gauge to determine if the rifle continues in service or not? I have a set of "GO", "NOGO" and "FIELD" for 30-06 - but I do not have "FIELD" gauges in other cartridges - so I made a bunch of circles cut from feeler gauge that I can slip behind a "GO" gauge to determine what I have for headspace.

Is NOT related to 303 British or No. 4 Lee Enfield, but will about drive one to be "nuts" to discover the Swede Regimental Armourer's "GO" gauge for 6.5x55 is LONGER than SAAMI spells out for their "FIELD" (Maximum) length - and the Swedes were using 6.5x55 for 30 years or more before SAAMI existed!!!!

In the SAAMI document, I have never found how they establish the "NOGO" gauge value - is not the minimum, nor the maximum, unless they define it somewhere's else.

I suspect is a significant issue only if using issued or commercial ammo? I hand load for most of my rifles - I set the sizing die to match to the rifle's chamber - I really do not care about a gauge value - within reason - nobody is going to be using my hand loads, and some - like my 9.3x57 - I have never, ever seen commercial ammo to buy, anyways.

It has been my practice to transfer the "end play" - "headspace" - on the 303 British to the shoulder of the chamber - so I pretty much ignore the rim as a headspace thing - but apparently this new-to-me 300 H&H will require me to use the cavity for the belt for headspace, as there apparently is not enough shoulder on that one.
 
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I found some very similar round sized shims that only needed their outer diameter trimmed/ground to fit and they worked for me to tighten up headspace on one of my LE's while also correcting the clocking with my limited collection of boltheads.

The one I used was brass I think, these below are stainless steel.

They came in a container like this -


91mb7Xmk6eL._AC_UF1000,1000_QL80_.jpg


4NFH5_AS02


500-1200pc-M3-M4-M5-M6-M8-304-A2-Stainless-Steel-Ultrathin-Flat-Washer-Adjusting-Ultra.jpg_Q90.jpg_.webp


20201207_140515.jpg


BoltHeadWear2-1.jpg


BoltHeadWear1-1.jpg


BoltHeadWear3-1.jpg
 
IDCA, your rifle is fine. Don't fix what isn't broken.

if you're looking to tighten up headspace, the easiest and cheapest way to do it, without changing anything on the rifle, is to fireform the cases for your particutlar rifle's chamber and thereafter, neck size only when reloading.

You need to be very careful when you start messing around with headspace on when they work off the thickness of the rim.

It may not be an issue today but it wasn't that long ago when rim thicknesses varied by several thousandths, between lots of the same manufacturer's cases.

Nothing beats fireforming the case and reloading it to extend case life as well as enhancing accuracy.
 
Go here - https://saami.org/wp-content/upload...99.4-CFR-Approved-2015-12-14-Posting-Copy.pdf

Scroll down to page 107 - for 303 British - is cartridge drawing on top half of page and chamber drawing on lower half of page. Note that SAAMI calls out rim to be .064"-.010", then "headspace" for the rim in the chamber to be minimum .064" and maximum .071". It seems based on gauges here that the NOGO gauges are mostly .004" longer than "GO" - so if "GO" is at .064", then "NOGO" would be .068" - not nearly as far from maximum as other cartridges like 30-06.

I do not know if Europeans or British follow these standards, if they follow CIP standards (if they are different?), or if they have their own standards. But pretty much most North American made ammo is going to be compliant with SAAMI, I think. I suspect most North American made headspace gauges likely follow SAAMI?
 
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bearhunter said:
IDCA, your rifle is fine. Don't fix what isn't broken.

if you're looking to tighten up headspace, the easiest and cheapest way to do it, without changing anything on the rifle, is to fireform the cases for your particutlar rifle's chamber and thereafter, neck size only when reloading.

You need to be very careful when you start messing around with headspace on when they work off the thickness of the rim.

It may not be an issue today but it wasn't that long ago when rim thicknesses varied by several thousandths, between lots of the same manufacturer's cases.

Nothing beats fireforming the case and reloading it to extend case life as well as enhancing accuracy.
Click to expand...

There is a way to ensure nearly "zero" end play in 303 British - was described some time ago on CGN - run new unfired brass into a die with a larger diameter neck - like 8mm or .338 - then into a 303 British FL size die to bring that neck down to size - but adjusting that sizing die to just so allow that "false shoulder" to create the "head space" - then you know the case head (rim) is tight to bolt head face when you first fire that round - after that, be careful not to push that shoulder back any more than you need to for easy chambering. The amount of end-play - "headspace" - is under your control by how much you push back that fired shoulder. If you want to do similar with store bought ammo, can use the O-ring trick to get about same thing.
 
tiriaq said:
What NO GO gauge? .068? .074? SAAMI is the former.

Shortening the bolt sounds like a bad idea.
Better to try different bolt heads until you find a longer one that also indexes, if you wish to reduce the bolt face/breech face gap.
Click to expand...

I have a full set of gauges marked as follows.

Go 064
No Go 067
Field 070
 
I Dont Care About You said:
The problem I have is the bolt head I'd like to use won't rotate far enough. ie it under rotates.
Click to expand...

If you say your rifle "barely swallows" the .067" gauge, is probable that you do not have an issue. Re-read post #9 - was not unheard of for armourer to stone the bolt HEAD if it under turned - I do not think was ever a plan to machine or stone the bolt BODY.
 
Pretty much as soon as I considered the notion of shortening the bolt body to allow the head to fit, I also realized that would likely result in too short headspace anyway and so would not solve the issue.

I purchased a lot of new old stock bolt bodies so I can swap out parts to see if I can hit upon a combination that tightens up the headspace properly. They weren't overly expensive and can be sold if I don't need them.
 
I have exchanged bolt bodies in Lee Enfield rifles, but as per the various articles by Peter Laidler on milsurps.com, I do not think that is a minor thing to do - is some stoning or at least checking that is required. I think the bolt and receiver were originally made / fitted to stay together - then the bolt heads were the parts that had a process / standards to swap out.
 
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Keep in mind that if your rifle "barely swallows" your NOGO gauge, you are only .003" over minimum, and no where near maximum. And all the commotion about head space in a No. 4 Lee Enfield, using those gauges, is only about clearance for the case rim - nothing, really, to do with the fit of the cartridge body to your rifle's chamber.
 
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