Kent's questions- from the picture thread

[jmoore]

Originally posted by Kent on pg 3 of this thread:

Lee-Enfield Mk1 No.4 rifle picture thread - Military Surplus Collectors Forums

Kent's post:

"Okay, a couple things...
What's a Trials Rifle?
When you talk about the "last four digits" and the "full serial number" you are referring to the number on the bolt, right? What info does the serial on the body tell you?

Do I have any benefit of keeping this Number 3 bolt and bolt head or to keep this Long Branch closer to its roots, would the best thing be to find a No. 4 Mk I bolt?

Also, the whole 'Headspace' issue I keep reading about didn't seem to phase the gunsmith I purchased this rifle from. He said that with Enfield's and their rimmed cartridge, the headspace is determined by the rim, so as long as every rim is the same, the headspace isn't affected. Can someone explain this to me or point me the right direction? Thanks guys."

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[jmoore]

I gotta attack the last bit first, because that's one I've never heard before!

While its technically true that if all the rims are the same, your headspace won't change, that does not begin to address whether or not the RIFLE'S headspace is within specifications. Whilst there's some variablilty in the effective lengths of bolt heads, as a rule No. 3 marked heads are the longest. You may find a No. 2 or 3 LB marked head that will gage properly, but does it stop rotation w/in specs? I'll try and find one of Edward Horton's threads that has pics and all.

Here's a very good thread to ponder (The second post, by Alan de Enfield, deals w/ bolt head overturn and other useful items to know.):

What to do about headspace after #4 bolthead? - Military Surplus Collectors Forums

I don't think this "'smith" is the fellow you want to use when dealing w/ Lee derived actions!




Here's a link for your "Trials rifle" question:

1933 No.4 Mk1(T) Sniper - Military Surplus Collectors Forums

[Peter Laidler]

Kent, I wrote a long article about the correct setting up of a No1,4,5and L39/42 bolt heads some time ago. If it's concerning you, you ought to read it. Someone with a better compu'a knowledge than me can resurrect the article I expect.

but whatever you do, don't go looking for a No4 bolt head!

[Badger]

Okay, a couple things...
What's a Trials Rifle?

This will help you ...

Check the 1933 No.4 Mk1(T) Sniper "Trials Rifle" (click here), located in the England - Milsurp Knowledge Library (click here).

Regards,
Badger

[Alan de Enfield]

Peter's old post on headspace :

Anyone for CHS?
Posted By: Peter Laidler
Date: Sun 4 May 2008 11:07 am
Quite why we have a thing called cartridge head space and the actual physics of it are not within the brief of this little article. What IS, is the act of CHS-ing a rifle. The first thing I ought to mention is that in Britain, certainly from the period that I was involved, from the early 60’s until today, the CHS for all of our .303” service weapons was that a bolt MUST close over a gauge of .064” thickness x .5” diameter that is inserted between the front face of the bolt head and the rear face of the barrel. Naturally, both surfaces must be clean!

On the other hand, the bolt must NOT close over a gauge of .074” thickness x .5” diameter that is inserted between the front face of the bolt head and the rear face of the barrel.

We call these gauges ‘CHS gauges’ and for ease of use in the UK Military, take the shape of approx 1” long cut down cartridge cases……….. You’ve all seen them! And to make things simpler still, we call them simple GO(the .064”) and NO-GO(the .074”) for obvious reasons. And just to clear up another ambiguity, we haven’t used other sizes at any level of repair since 1948 so far as I can ascertain…………………..
Our gauges are ‘calibrated’ annually. Given that you now have your set of gauges, ‘calibrating’ them is quite simple. Get a micrometer, clean the rim faces of the gauges and holding the micrometer square, simply measure the thickness of the rim! Now, I’ve got a confession to make…………. If your gauges are slightly worn to, say, .063 or 2 or, say .073 or 2, then given that there is .010” leeway anyway, does one or two thousandths of an inch make any difference? I say not but if you insist……….

Quite whether the bolt ‘goes’ or ‘doesn’t go’ is dependent upon three things and THREE things alone. There is NOTHING else. They are the locking surfaces of the body, the locking surfaces of the bolt and wear on the surface or mating surfaces of the bolt/bolt head or a combination of these. There are some that will say that wear on the rear surface of the barrel is relevant. Quite HOW this wears is a mystery because it is only subject to the brass cartridge case closing up to it, albeit many thousands of times in its life………. That is only my opinion. Other Armourers say that some wear will be caused by gas wash from……… well ……... Whatever the opinions you can accept that wear IN the barrel has no bearing on CHS.

Now, to cater for the vagaries of mass production, the designers cater for two of those points, the bolt and the bolt head. Why not the body then you ask? Once again, I can only sing from the hymn sheet that I know. That’s because in the UK Military, bodies were classed as the ‘MASTER COMPONENT’ and the master component was NEVER available from Ordnance Stores. NEVER, NIX, not EVER, contrary to what your grandma’s uncle Jim who knew a bloke whose friend met someone in the NAAFI at Tidworth might have told him. It was, is and always has been a blocked VAOS number. I know that it’s shown and illustrated in the parts list but just remember this. The parts list is a list of parts and not a list of AVAILABLE parts.

Now to the point of technicalities. In an IDEAL world, the world of an examination bay at the factory or a large Base Workshop, the gauges would be slipped into the breech and a completely stripped bolt and bolthead would be closed over the gauge. This is the way that it was done at Base workshops where 1000 rifles would be stripped with just the bolt and bolt head (plus the fore-end and backsight, to make life easy when reassembling after Base repair) tied to the rifle with a bit of string. It’s easy then but we don’t live in an ideal world, but a REAL one where the gauge is slipped in place with the rifle assembled. It this case, it’s important that in order to prevent chipping the expensive gauge with the extractor, that it’s slipped onto the bolt face and under the extractor, just as happens in real life. For this you’ve got to realize that the round is fed up into the chamber by sliding up the bolt face and under the claw of the extractor. And that is the reason why the bottom edge of the extractor is everso very slightly rounded - , oh yes it is, just take a look…….., so that it doesn’t tear away at the brass case as it’s sliding up the face of the bolt while being fed into the chamber and eventually clog up the breech end with brass chippings and residue! You can see now that unless you actually hand-feed a round into the chamber, then the extractor never actually clips OVER the rim of the round. The rim of the round actually slides up the bolt face and UNDER the claw.

Now that the gauge is into the chamber and the bolt is being closed, this is where the trouble lies. It’s important here to remember the often said phrase among Armourers of ‘DON’T OVER CHS’. Here’s another thing to remember during this. Because there is a camming action operating while OPENING the bolt, called ‘PRIMARY EXTRACTION’ this action also operates when closing the bolt. And the same primary extraction forces that will enable the infantryman to force the bolt closed and unlock and extract a possibly distorted shell case, covered in wet silt and mud in the saltwater magrove swamps of Johore in Malaya that’s caused the case to stick hard to the chamber walls will also enable the butchers or bubbas to close the bolt hard against the gauge. NO-GO on the .074” gauge is when, using the lightest finger and thumb action on the knob causes a slight feel of resistance.
The next question you’re going to ask is ‘….where during the bolt closing movement is this slight feel of resistance acceptable --- Is it almost closed or, hardly closed or inbetween’? Good question and the answer in the bible reads thus: ‘…with a 0, 1 or 2 bolt head, there must be resistance onto the .074” gauge prior to there being a minimum of .050” from the underside of the bolt lever to the contacting point of the body socket’. Then it goes on to say ‘…….With a No3 bolt head the left edge…………..’ But I want you to forget this because the statement was too ambiguous. I suggest that you use my maxim of ‘WITH ANY SIZE OF BOLT HEAD FITTED THERE MUST BE RESISTANCE OF THE BOLT ONTO THE .074” GAUGE PRIOR TO THERE BEING A MINIMUM OF .050” FROM THE UNDERSIDE OF THE BOLT LEVER TO THE CONTACTING POINT OF THE BODY SOCKET. I want the master Masons among you to learn that by rote!

Using this criteria, if a No3 bolt head starts to resist half way closed and a No2 resists at .051” from the body side, then use the No2 bolt head. Remember DON’T OVER CHS

There are a couple of reasons for this. Firstly, it is from a point when the underside of the bolt handle is approx .15” from the sharp curve between the top of the body and the side of the butt socket, that the bolt effectively ceases to move any further forwards and is effectively locked.
The second is that prior to the point of fully locking, a feature called ‘mechanical safety’ comes into operation and (it’s getting technical now……….) the stud on the cocking piece will strike the stud between the short and long cam groove at the rear of the bolt causing a diminished force of blow to the striker, resulting in a mis-fire! Phew!
You will understand that this is a highly condensed précis of events taking in months of learning, investigating and examining undertaken by apprentices and I’m trying to cram it into a 40 minute lesson!
This brings me to another point……… I asked you to read and digest the discussion between KimW and others of some weeks ago. It’s very basically this. If you cannot get headspace, even using the very relaxed criteria I have discussed here by using a new bolt and a No3 bolt head, then I’m afraid that it means your body is knackered. This quaint old Armourers technical term indicates that it’s seen better days ….., it’s xxxxed! You COULD allow yourself up to, say, .078” headspace but the technical opinion reached during research into this during the 50’s is that it’s a palliative and not a true cure.
Next, We’ll discuss the odd-ball .303’s such as the Vickers and the Bren plus the 7.62mm L8’s, 39’s, 42’s and the Envoy group. Are you still in for the long haul?

Anyone for CHS, part 2
Posted By: Peter Laidler
Date: Mon 5 May 2008 10:33 am

The No1 rifle is not exactly my forte as those I encountered during my service were those well worn training school examples, a few in Malaya, mainly held in mobilization stores and grenade launching and those live and DP versions held by Cadet Forces. Maybe a few thousand in total.
The mechanics of CHS for the No1 rifle is a little different. The same criteria applies but this time the last EMER dated 1956 for the No1 rifle simply states that the bolt should close over the GO .064” gauge and should not close over the .074” NO-GO gauge. Sounds simple enough to me! From this I always use the No4 rifle criteria of;
THERE MUST BE RESISTANCE OF THE BOLT ONTO THE .074” GAUGE PRIOR TO THERE BEING A MINIMUM OF .050” FROM THE UNDERSIDE OF THE BOLT LEVER TO THE (its) CONTACTING POINT OF THE BODY SOCKET. So if your bolt starts to resist at .056” or so from its contacting point of the rifle body socket, then if that’s good enough for the Army, it’s good enough for me and hopefully you!

There has been talk of some bolts being ‘ground away’ on the underside of the lever. Quite why is a mystery and my older mentors are unsure why because what will eventually prevent the bolt rotating is the long cam contacting the body side as it’s locked down to the right!
Spare bolt heads issued from the factory were actually oversize and marked with a small ‘S’….., but nobody can tell me by how much! Other Armourers of the period have told me, only yesterday over a frantic phone call, that this is incorrect but they WERE all to the longest specification. Whatever it is/was, there should be room to stone to size. And THIS is where Armourers were always taught DON’T OVER CHS. Or in this case, should that read don’t UNDER CHS. If your rifle closes on the .074” NO GO gauge, this is what you do. Go to the No1 bolt head drawer and select half a dozen bolt heads that don’t overturn by more than 10 degrees (later, 15 degrees was permitted to make best use of remaining spare parts stockpiles), the bolt face is not ringed sufficient to allow the escape of gas past the primer and the striker hole is not greater than .084” dia. Try them all until you get the best fit. If necessary machine or stone the bolt head square and true until it closes over the .064” gauge and doesn’t close over the .074” gauge. The point at which the bolt doesn’t close prior to the .050” limit is academic because so long as it doesn’t go/close, it’s passed the test.

Now, how you shorten the bolt head it is up to you. You can machine it in a lathe if you like but some are quite hard, or surface grind but I was taught that the best way was to rub the face down on a sheet of ‘400’ wet and dry carborundum paper on a sheet of glass, just covered in slow running water. Go round and round with equal pressure, rotating the bolt head slightly every so often, taking a gnats knacker off at a time for several minutes and trying it again and again. Every so often, smear a smidgin of engineers blue on the rear of the .074” gauge and close the bolt head lightly against it to ensure a crisp round witness mark on the face of the bolt. This is the acid test of it being perfectly square to the bore. Be sure to remember these old Armourers technical words such as ‘gnats knacker’ meaning something too insignificant to be measured and ‘smidgin’, indicating a quantity equivalent to a gnats knacker.

That is very basically it! Once again, this is weeks of practice in the classroom and on the bench with discussion groups all put into one short period. And if we destroyed a rifle or bolts and boltheads while learning our trade ….., who cared so long as we learned and got it right eventually.
Next is the one we’ve all been talking about…….., the 7.62 variants. Are you STILL in for the even longer haul?

Anyone for 7.62mm CHS?
Posted By: Peter Laidler
Date: Tues 6 May 2008 11:36 am

Now for the biggie, the 7.62’s. The basic principle of headspacing hasn’t changed here but the practicalities have. Whereas before, on our rimmed .303” rifles we measured the GO NO-GO distance between the front face of the bolt and the rear face of the barrel, it’s all changed for the rimless 7.62mm NATO caliber rifles. Now we have to measure from the front face of the bolt to the cartridge seating at the neck. Well, that’s all pretty clear then ….., except that the neck is tapered so where EXACTLY on that neck do you take your GO, 1.628” and NO-GO 1.635 measurement from? Even if I told you it’d make no difference whatsoever because without the specialist measuring and more importantly, the calibration equipment, you’d still be none the wiser. The trouble with this is that you’ve got to take the word of the manufacturer of the gauge. And exactly where does HE take HIS measurement from but more importantly, WHO does he get them from. geting difficult isn't it?
Let me give you an example. My GO gauge gives you a close/GO reading of 1.628 but Bloggs & Co gauge may give you a GO reading of 1.575” for the same 7.62mm caliber. How can there be a difference of .053” between the two when they are identical? Well, it’s simple really. Our STANAG gauges are measured from one diameter around the neck while Bloggs & Co are taken from a different but larger diameter .053” further to the rear! That is really all I want to say about that.

The next obvious question for all you enthusiasts is where can I get a set of these gauges and the true answer is that I don’t know!
The fact remains that there are MANY gauges for all manner of 7.62mm rifles and machine guns ranging from the little bolt action L8’s right through to the L- whatever it is ferocious mini gun. And there are equally MANY for different lines of repair and functions, ranging from 1.622” to 1.648”.


That just about covers the 7.62mm versions. The question of calibrating your gauges is one that needs to be looked into by ‘some friends’ on both sides of the pond. I can see already that this is about to open up a whole new can of worms...... But just hang on in there....................

[Surpmil]

Oh my, did I start all that? Sorry Kent, I didn't notice your response.

I think your other questions have been answered, but what I meant was that if the renumbering of the bolt was done by a military armourer, it would be the full 22L---- serial number, not just the last four digits. Whoever did it no doubt didn't have an "L" stamp, so that's why only the last four!

It get's confusing when you're new to the Enfield world, but No3 in reference to the bolt head refers to it's length, not the No4 etc. of the rifle model. Bolt heads came in 0, 1, 2, and 3 sizes with 3 being the longest. One of the nice features of the Lee Enfield is that headspace can be changed by just changing the bolthead to a longer or shorter one. The No3 bolt head is probably the most unusual and with the wear that you see on older rifles sometimes, that size is often needed to 'make up for' the metal worn off the bolt lugs and their contact surfaces in the rifle "body" or receiver. That's what I meant by saying the most desired; ie: the size many people are looking for to get correct headspace in their now pretty old and worn rifles. Rifles which would not headspace correctly with a No2 bolthead were condemned in British service I believe Peter has told us, and that was probably true in other Commonwealth countries using the No4 Lee Enfield.

My guess would be that the bolt in your rifle being non-original, is too short or too worn for that body (receiver) and the person who fitted it has tried to make up for that by fitting the longer No3 bolthead. I very much doubt the surfaces the bolt rubs/bears against are worn, given that the rifle looks almost new, and I believe that is the original finish on the metal.

What you really need is a newish looking Long Branch bolt, preferably without serial number, that you can have lapped in and headspaced correctly.

Here's a couple of photos showing the beveling on Long Branch and Savage bolt heads. MkI* rifles like yours need this type, or else need the one they have modified like this, if you're handy with a needle file.

As the bolt is worked back and forth there is sometimes a tendency for the bolt head to lift slightly as it goes past the slot and sometimes it lifts enough to catch on the edges of the slot, chipping the corner of the slot and making the rifle unuseable as the larger the slot becomes, the more easily the bolt head can 'escape' the guide rail or rib and repeat the process. The MkI* modification was not a good idea.

Here's a couple of photos. Often the beveling is much more pronounced than this.