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Please point me towards an official chamber diagram for the Lee Enfield rifle. If different depending on model/arsenal then I'm looking for the one used last for the No. 4 Mk 2 at Faz. I'm particularly interested in the dimensions of the neck, throat and lead.
I found this one with the help of Google. Anyone have a better one?
https://www.milsurps.com/images/impo...o6jxputp-1.jpg
Thanks.
Keith
Seems you found one of my image compilations. Top portion is SAAMI. Bottom is from a UK military blueprint of the SMLE MkIII*. Not really much difference between the two - once one subtracts headspace from the SAAMI lengths.
Despite tales of wide variation, I find no significant difference between chambers of my 1943 Lithgow SMLE III* and 1953 ROF(F) No.4 Mk.2. Fired cases interchange perfectly and shoot the same loads with comparable accuracy. Fired cases also interchange in my ROF(F) No.5 Mk.1 - but accuracy isn't on par.
Are you planning to make a chamber reamer?
No, not a chamber reamer, but custom match bullets. The guy who is helping me is a bench rest guy and needed info on throat and lead to determine if the bullet design he has will work.
Keith
The trick would be this:
1. If using "commercial" bullet forming equipment, such as supplied by Corbin, etc, go with a flat-based, hollow-point design.
2. Match the exterior profile of the "proper" Mk 7 bullet.
3. Select a core that will give correct weight for the finished bullet.
4. Don't bother with the aluminium / fibre "nose filler", just leave an air-space to "replicate" as best as possible, the "base-heavy" balance.
Some "fiddling" will be involves as the original jackets are a bit thicker than many modern "sporting" jackets.
The key characteristics are:
Overall length
Total weight
Balance
And, of course, diameter. On this last item. give serious thought to a nominal diameter of 0.3125" instead of the "usual" 0.311".
Final "touch" would be to slightly "dish" the VERY flat base: ABSOLUTELY NO boat-tails.
Get the profile / shape wrong and they will not seat or feed correctly. Neither will they come close to tracking "original" exterior ballistics much past 200m.
Always remember: Any Lee Enfields (or P-14), and we can probably include the Ross, made much after 1912, and certainly post WW1 SMLEs, No4s and 5s, were built AROUND Mk7 ball. The rifles were tuned to the ammo,, not the other way 'round.
In Corbin terms, you want a concave open base with base round over die set, 8.2 ogive
Wise words there from Bruce in Oz, (thread 4; last para.) that Armourers were told to ignore at their peril. That the BULLET is the weapon. The case and propellant are the means of moving it on its way and all the rifle does is to point it in the right direction and impart gyroscopic effect to aid its accuracy
I have asked for official British ordinance drawings many times but I have never seen one. There are no drawings to date that dimension and tolerance both the chamber and cartridge.
I got all of the data used by a leading maker of reloading dies. All his data was from both commercial and military sources in the UK. None of the drawings were fit to manufacture anything.
I have once fired brass from probably a dozen different rifle #4 rifles and the chambers vary significantly.
Some other considerations;
1. Make the jacket thick as possible depending on material costs
2. The projie even made to the Mk VII spec's may not have the same ballistic properties of the original round Why - simple we do not use cordite any more and the differential in burn rates could or may send different harmonics along the barrel maybe not enough at say 100m but a 600m it could be a different POI than whats on the sight ladder so more range time to get the correct elev thats gotta be good for us all!
3. I would make them a FBHPSB at .312 as these girls are getting older the .312" obturates better as I found with two other types the 170gn FBHPSB Taipans and the 150gn Hornadys FBSPSB both at .312" and shot well out of all the ones I use at the range
4. Cost/round like all things we like they are getting more expensive so cost and freight come into play especially when you are interstate or o/seas
5. And I suppose it is coming as those that cuddle trees demand we have lead free projectiles as we are polluting the earth may be another consideration for future production
6. Why don't you contact Ian Skennerton or Brian Labudda or even try the Lithgow Museum and see what they can do for you some one will have something
CNC turned solid bronze with several grooves to accommodate the metal displaced by the lands? Look, Ma; NO LEAD!!
Good point about the Cordite as well. It burns fairly quickly compared to modern ideas about "ideal" burn rates.
However, given that the U.S. and Canada made vast quantities of "Mk7" ball ammo, in BOTH world wars, What were they using to fill all those millions of rounds?
Some Canadian production used Cordite propellant and Mercuric primers, but to the best of my knowledge ALL U.S. production was fuelled by granulated, double-based Nitro-Cellulose propellants and ignited by lead-based Boxer primers.
And then there is the substantial output of .303 Ball and Tracer from the FN plant, especially post WW2. I suspect that they would have put some effort into matching "standard" Mk7 ballistics at least for the ball ammo, especially as much of this production was shipped in cases and packets labelled, "Pour BREN".
I will dig around in the crypt.
Somewhere there should be complete drawings for SMLE and No4 barrels, complete with dimensions and tolerances for the chambers.
In theory, the cordite Could cause a difference, but as millions of rounds were loaded and fired with N-C powder, and we have probably all used surplus so loaded, I don't think it is a real problem.
The bullet is critical. By that I mean it should be as close as possible to the Mk V11 in design, and if so, will stabalise with the right powder.
As we are mainly using well-used barrels, I also think .312" or so could be a help!
Bruce I am not sure how the monolithic projies would go and I think we would probably have to many people digging up the mantlets and becoming a hazard trying recover the bronze to sell to the scrap dealers....LMAO :lol:
Oh yes I have used surplus alright the good old P.O.F and grand stuff it is in fact it is so good you would think you are shooting a percussion rifle click --------wait--------bang---------and wads of confetti out the muzzle with a wishful thought of now where the hell did that shot go!!!!!!. As the other stuff headstamped WWII vintage Mk VII like MW, CAC, MG, RG and so on are now collectible unless you have a few 0000's rounds tucked away just too good to throw down the range.
Ross' version for the Mk.III Rifle, circa 1912/3
"'E was warned agin' 'er, that's what made 'im look.":D
LeHigh Defense has been turning out boat-tail copper match solids for quite some time now: 150 gr. .311" and (now discontinued) 180 gr. I was going to experiment with turning the 180 grainers into flat base bullets of which I have a box or two still kicking around but why bother now that they're no longer being made. Even with being boat-tails they are very accurate and have excellent BC's.Quote:
Originally Posted by Bruce_in_Oz
.311 diameter, 150 grain Match Solid Bullets (50 count)
Quote:
Originally Posted by Bruce_in_Oz
It doesn't matter how good the bullet is if the barrel is worn.
Interesting comments 'from the period' (1949)
Note : Cordite was used in all British 303 produced ammunition !
Use of Cordite in Rifles
'Regulations For Army Ordnance Services', Vol.3, Pam.11A (1949) comments:-
USE OF .303-IN CORDITE AND N.C. AMMUNITION
1. The action of Cordite propellant in the barrel of a .303-in. weapon is quite different from that of N.C. propellant.
Cordite gives a rapid build-up of pressure with great heat, leading to pitting and erosion of the chamber end of the barrel.
N.C., however, gives a more gradual build-up of pressure with less heat, and this in turn gives uniformity of barrel wear from chamber to muzzle, the amount of pitting and erosion being greatly reduced.
2. With Cordite propellant, set-up of the bullet is most pronounced and even when the chamber end of the barrel is well worn, the muzzle end still has sufficient rifling left to impart the necessary spin. As the wear advances up the barrel, so the accuracy of the weapon is progressively reduced.
With an N.C. propellant, set-up of the bullet is slow and by no means so pronounced, due to the more gradual building up of pressure. The barrel retains its original accuracy until wear reaches a critical stage, when a sudden falling off in accuracy occurs.
3. It can be seen by comparison with the effects of barrel wear that to use N.C. ammunition in a barrel which has fired Cordite will give serious inaccuracy in flight, whereas the use of Cordite ammunition in a barrel which has fired N.C. gives good accuracy, but serious changed the wear pattern of the barrel.
In the first case, i.e. a weapon which has fired Cordite ammunition the barrel will be eroded and fissured in the first few inches up from the chamber, the part in which obturation should occur. The poor set-up of the bullet, in the N.C. cartridge is not sufficient to give good gas sealing in such a barrel and the bullet does not, therefore, receive the maximum impulse. The resultant loss in velocity and instability due to lack of spin lead to a high degree of inaccuracy.
In the second case, Cordite ammunition fired from a barrel which shows uniformity of wear from firing N.C. ammunition, has an adequate reserve of set-up that ensures full gas sealing, with satisfactory velocity and spin. Unless the barrel wear is in a advanced stage due to firing a large number of N.C. rounds, there will be no immediate appreciable loss in accuracy. Furthermore, the decline in accuracy for Cordite ammunition will follow the normal gradual fall-off experience in weapons firing Cordite alone, as the wear at C of R progresses.
4. Trials have proved that even if only a few rounds of Cordite ammunition are fired from an "N.C." barrel, the ensuing accuracy life when N.C. is subsequently fired is reduced considerably. The occasional and restricted use of N.C. in a "Cordite" barrel will however, have little effect on its ensuing accuracy life for Cordite, although naturally the fire of N.C. will not be very accurate.
5. The effect of wear of barrels can be determined by firing shots through a paper screen at 100 yards. If, on examination of the screen, all shot holes are not perfectly round, then the barrel is no longer fit for use.
The danger lies in the fact that bullets fired erratically from badly worn barrels may overcome their instability in flight and take up a steady flight in the direction in which they happen to be pointing, with short-ranging and disastrous results if used for overhead fire. Except under these conditions of long-range firing there is no risk involved, though in normal range firing inaccurate fire will result.
6. The following instructions regarding the use of .303-in ammunition have been issued to users and are governed by stocks and types of ammunition and weapons in current use:-
(a) .303 in. Vickers M.G.s in M.G. Bns.
(i)Mk.8z only will be used for overhead firing.
(ii) Mixed belts, i.e. Ball, Tracer, A.P., etc., will NOT be used.
(iii) Any barrel which has fired Cordite ammunition will NOT be used for N.C.; barrels will be stamped “7” on the trunnion block and returned to R.A.O.C. through normal channels.
(iv) Barrel life for N.C. will be assessed by unit armourers using the appropriate gauges.
(b) .303 in. Vickers M.G.s in A.F.V.s.
Here the overhead fire problem is not considered; the range is usually less than is the case with ground M.G.s. tracer ammunition is required as an aid to fire control, and prolonged fire programmes are not envisaged. Special mixed belts of Mk.8z and Tracer are provided in boxes clearly marked “For use in A.F.V.s only”. The reduced life of the barrels is accepted.
(c) Light M.G.s.
Cordite ammunition normally will be used. N.C. ammunition, however, gives a relatively small flash at night and if the Bren is being used for a special purpose, e.g., on a patrol, its use is permitted.
(d) Rifles.
N.C. ammunition will not be used in rifles except in such circumstances as quoted in para. “(c)”
above, if necessity should arise.
7. Belt packed S.A.A. for M.G.s is packed in boxes which are clearly marked with labels or stenciling indicating its proper use. It will never be de-belted and used for practice purposes in L.M.G.s or rifles.
8. It must be noted that the above restrictions apply only to ammunition fired from British weapons. All American ammunition is N.C. loaded and their weapons are designed to fire it satisfactorily.[/I]
A d E
I have used Mk6, M7 and others that i turned into Open Based projectiles with NC powders with OK results. Not to 1000yds. The open base with a deep pocket pushed like Mk8s worked. BTs were just not there. Hornady produced an OBBT .. When turned into a Mk7 was pretty dam good.
Quote:
Originally Posted by Bindi2
Yes - BT bullets and NC powders are usable and can give good results - but, not if the 1st 3" or 4" (or more) of rifling no longer exists, having been burnt out using cordite.
That is why the 'simple barrel check' of pushing a 303 bullet into the muzzle does no good at all. It may be fine for rifles that have shot NC but a rifle that has spent its life shooting cordite can have a perfect muzzle and no rifling from the throat forwards.
It is interesting that similar information is provided elsewhere :
2) Mark 7 .303-in S.A.A. has a cordite load and a flat based bullet. He same applies to .303-in tracer and .303-in AP
Mark 8Z .303-in S.A.A has a neonate load and a streamline based bullet. Trial firings have proved that these two types of ammunition do not wear the barrel in the same manner. Barrels which have been used for Mk.7 or .303-in Tracer or AP become inaccurate much sooner when Mk8Z is used in them, than barrels in which Mk8z only has been employed.
3) One of the advantages of Mk8Z ammunition is that the barrel maintains accuracy and elevation until the actual moment of collapse. No indication of approaching barrel failure is given when Mk8Z ammunition is used. Accuracy is liable to break down very suddenly and the barrel becomes dangerous for use for overhead fire in the later stages of its life. To ensure the safety of our own troops during overhead fire by medium machine guns, the life of a .303 Vickers gun barrel using Mk8Z S.A.A has, therefore been fixed at 10,000 rounds (or 40 belts). This figure is well within the number of rounds successfully completed by the earliest failure of barrels firing an endurance and accuracy test under conditions of excessively rapid rates of fire. If, however, even a few rounds of cordite loaded S.A.A. are fired, the Mk8Z accuracy life drops considerably.
A d E
the Mk7 with NC in worn Cordite used barrels does work. As PL has said you only need 4 to 6 inches of rifling to stabilize the Mk 7 projectile. The kick in the nether regions is the secret. BTs are hopeless. Flat base turned into a sort of open base do better. Open base BTs turned into Mk7s work very well. Open based 215gn Mk6 are one of the best DG 303 rounds i know.
Quote:
Originally Posted by Bindi2
That does seem to be contradictory with the army Small Arms Ammunition manual which states :
Extract 1 :
The action of Cordite propellant in the barrel of a .303-in. weapon is quite different from that of N.C. propellant.
Cordite gives a rapid build-up of pressure with great heat, leading to pitting and erosion of the chamber end of the barrel.
N.C., however, gives a more gradual build-up of pressure with less heat, and this in turn gives uniformity of barrel wear from chamber to muzzle, the amount of pitting and erosion being greatly reduced.
With Cordite propellant, set-up of the bullet is most pronounced and even when the chamber end of the barrel is well worn, the muzzle end still has sufficient rifling left to impart the necessary spin. As the wear advances up the barrel, so the accuracy of the weapon is progressively reduced.
With an N.C. propellant, set-up of the bullet is slow and by no means so pronounced, due to the more gradual building up of pressure. The barrel retains its original accuracy until wear reaches a critical stage, when a sudden falling off in accuracy occurs.
Extract 2 :
In the first case, i.e. a weapon which has fired Cordite ammunition the barrel will be eroded and fissured in the first few inches up from the chamber, the part in which obturation should occur. The poor set-up of the bullet, in the N.C. cartridge is not sufficient to give good gas sealing in such a barrel and the bullet does not, therefore, receive the maximum impulse. The resultant loss in velocity and instability due to lack of spin lead to a high degree of inaccuracy.
The NC powders in use today are somewhat different to what i used back in the late sixties. Maybe higher pressures bump the rear better or a longer pressure curve with slower powders. I know all about barrel burnout and how quick one goes when it starts with BT projectiles. You can almost see molten steel being pushed out of the barrel.
If it any help this is the one published in the book "Textbook of Small Arms 1928"Quote:
Originally Posted by cprher
It is the military dimensions of the cartridge and chamber.
Note - non of this 'namby pamby make it thin' requirement as per the SAAMI drawings 0.064" +0/-0.01" (military requirement for case rims was 0.058" to 0.064")
Attachment 133348Attachment 133349
And the chamber dimensions from the 1943 dated blueprints (engineering drawings) for the No1 Mk3 which I think you have already seen.
I have the set of fully dimensioned drawing of every part and component of the No1 Mk3 but they are too large to post on the forum.
A 'small fraction' of one of the series of drawings :
https://i.postimg.cc/s2v2ZCWS/No1-Mk...mensions-2.png
https://i.postimg.cc/rFrCx7SB/Screenshot-2292.png
"Mil-Spec" .303 chambers are just weird.
From the very beginning to at least the No4 days, they were NOT cut using "modern-style", one-piece 'reamers.
They were cut using a series of odd little short reamers, one for each "feature" of the chamber. There was a =n associated set of gauges used to measure each different stage.
The best bit is that final "setting" of the chamber was achieved by firing a "special" cartridge closely related to a "proof' round, to settle the insides of the chamber AND "final seat" the barrel, bolt and body assembly. Remember that all of those Lee Enfields were made from various grades of metal ranging from glorified "mild steel" to malleable cast iron.
I will see if I can find the full description of the process in my tree-ware files.
Let's face it: NOBODY was expecting to be reloading the "once-fired" brass, especially on the two-way range. As long as the brass case sealed the pressure in the barrel and was then extracted in one piece, NOBODY cared.
And then, there are all the "surplus" rifles that have had their chambers"freshened-up" for commercial sale. On a rimmed case this is bad enough, but when you start seeing WW2 Mausers with a millimetre of headspace BEYOND the "No Go' gauge, sphincters start to twitch.
The past is an "interesting" place.
There is an excellent booklet (63 pages) that explains the manufacturing process of the Lee Enfield barrels. It is a 'modern' compilation of a series of articles ("Machining The Lee-Enfield Barrel - Operations and Fixtures Employed" written for 'Machinery Magazine' & published in 1916.
Booklet called "Making Rifle Barrels" and is ISBN 1-55918-280-6 Reprinted by Lindsay Publications in 2002.
Example of a couple of the many pages on the chamber :
Edit apologies that the pages are on their side - I cannot seem to be able to rotate them.
https://www.milsurps.com/images/impo...40746531-1.jpg
https://www.milsurps.com/images/impo...14074711-1.jpg
Allow me.