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About accuracy

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The Armourer View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote The Armourer Quote  Post ReplyReply Direct Link To This Post Posted: August 31 2020 at 12:30am
Just a little more info about Mk7, Mk7Z & Mk8Z  F of M




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britrifles View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: August 31 2020 at 5:01am
Thanks Armourer, this is what I was looking for.  What is the source of this Table?  

An estimate of the Mk 7 and 8 ball service ammunition grouping capacity is therefore 4 MOA based on a FOM of 8 inches at 600 yards.  This is calculated by multiplying the FOM by 3 and dividing by 6.  

Goosic, the best I can figure is that the Mk 8 ammunition pressures remain within the maximum pressure of the .303 cartridge.  We have another thread on this subject, how the British measured pressures differently than the US and used a copper crusher on the base of the bolt (measuring thrust load then using a conversion table to estimate chamber pressure).  The US method uses a radial crusher by tapping the chamber.  The British method measures a lower pressure value for the same actual peak chamber pressure.  The British Mk III Proof Pressure round was set to produce 25 TSI, this was used to proof rifles produced in WWII.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Goosic Quote  Post ReplyReply Direct Link To This Post Posted: August 31 2020 at 7:12am
The source supplied is from a British Ministry of Defense publication and goes on to state a working pressure of 49,000 C.U.P. for the MkVIIz and 47,000 C.U.P. for the MkVII with barrel life being reduced after 6000 rounds of the MkVIIz being used and 10,000 rounds of the MkVII being  used respectively.

Army Ordnance Services Part 7 : Pamphlet No11 Small Arms Ammunition Issued by the War Office - 24th February 1945 (Extract from 131 page document)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: August 31 2020 at 7:37am
Is this Pamphlet available on line?  Looks like a good reference.

Not sure I understand the barrel life numbers, Mk VII (Cordite) would be much more erosive on the rifling than Mk VIIz (powder).  These numbers seem backwards.

The working pressure of 49,000 CUP may be the values that would be obtained by the US Radial Copper Crusher method, and are higher than SAAMI max of 45,000 CUP (not surprising).  The common figure published for Mk VII Ball is 19.5 TSI which equates to 43,680 psi and uses the the base crusher method with an oiled cartridge which is said to give about 4/5 of the pressure measured by the radial method.    


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Post Options Post Options   Thanks (0) Thanks(0)   Quote The Armourer Quote  Post ReplyReply Direct Link To This Post Posted: August 31 2020 at 10:03am
Originally posted by britrifles britrifles wrote:

Is this Pamphlet available on line?  Looks like a good reference.





Not only 'on line';, but 'available here'

I was going to post it here but it seems Pdf's are not allowed on the forum, so, if you want a copy, send me a pm with your email and I'll gladly send a copy to you.

(page 92)




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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: August 31 2020 at 11:15am
PM sent, and thank you!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote The Armourer Quote  Post ReplyReply Direct Link To This Post Posted: August 31 2020 at 11:52am
Originally posted by britrifles britrifles wrote:

PM sent, and thank you!

Info sent (and a couple of extra pamphlets you may find interesting) there are about 30 'pamphlets' covering everything from setting up a range, to use of rifles to machine guns as well as ammunition.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Shamu Quote  Post ReplyReply Direct Link To This Post Posted: August 31 2020 at 1:52pm
You can post .PDF files on here! I do it frequently!
Go to the "Post Reply" button on the bottom right, not "quick reply".
Now click on the "Clamp on a file folder" icon at the top of the dialog box (6th from left edge).
The dialog box opens & you browse then upload just like the image uploader does with images.
to post the file just click on the same icon & a list of all your stored files appears. click on the file you want to use then hit "OK"!
To open the file just click on the link, like this one Thumbs Up:
Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote The Armourer Quote  Post ReplyReply Direct Link To This Post Posted: August 31 2020 at 2:10pm
Originally posted by Shamu Shamu wrote:

You can post .PDF files on here! I do it frequently!
Go to the "Post Reply" button on the bottom right, not "quick reply".
Now click on the "Clamp on a file folder" icon at the top of the dialog box (6th from left edge).
The dialog box opens & you browse then upload just like the image uploader does with images.
to post the file just click on the same icon & a list of all your stored files appears. click on the file you want to use then hit "OK"!
To open the file just click on the link, like this one Thumbs Up:

OK - lets try : No8 Users manual


Failed - the maximum size allowed is 1.0Mb

Many of my manuals are 100's of pages - even the little (13 page) No8 Training Rifle Owners Manual is 1.9Mb

My "1924 Ammunition Manual" is 21Mb and 270 pages.




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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: August 31 2020 at 7:37pm
From Section 7 of Pamphlet 11, instructions to holding units of ammunition that is suspect of deterioration were to be “proofed”.  This was not the same use of the term “proof” as in firing a proof pressure cartridge to proof a barrel or action.  It was to check on the serviceability of the ammunition. 

Paragraph 30 of Section 7 gives the maximum acceptable Figure of Merit for .303 Mk 7 ball as 12 inches at 500 yards when fired from the shoulder by a marksman with the rifle supported off sandbags (either Prone or on a bench).  The approximate extreme spread group size would be 36 inches (3 x FOM), over 7 MOA. 20 shots were to be fired to calculate the FOM.  Ammunition that did not meet this standard was retested, and if failed, it was sentenced as unserviceable. 

So there you have it.  Production acceptable FOM of 8 inches at 600 yards (approx 4 MOA extreme spread) and for ammunition held for service use acceptable FOM of 12 inches at 500 yards (approx 7 MOA extreme spread). 

So, we can’t expect the No. 4 rifle to shoot 2 inch groups at 100 yards when the ammunition was grouping as large as 7 MOA.  Clearly any such claims had to be based on very carefully selected and tested ammunition that fell outside the norm.  It may be lost to history exactly what was used to perform the accuracy acceptance tests of the Lee Enfield service rifles.  



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Post Options Post Options   Thanks (0) Thanks(0)   Quote Goosic Quote  Post ReplyReply Direct Link To This Post Posted: August 31 2020 at 7:49pm
Originally posted by britrifles britrifles wrote:

So, we can’t expect the No. 4 rifle to shoot 2 inch groups at 100 yards when the ammunition was grouping as large as 7 MOA.  Clearly any such claims had to be based on very carefully selected and tested ammunition that fell outside the norm.  It may be lost to history exactly what was used to perform the accuracy acceptance tests of the Lee Enfield service rifles.  
Would it be acceptable then to forego trying to find what was and possibly set a new standard of accuracy based off of what some of us are capable of achieving with our own select handloads and our standards of accurizing the Enfield and setting our findings to print to be shared with the rest of the shooting world?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: September 01 2020 at 5:39am
Goosic, yes of course.  The search for accuracy never stops.  Ultimately, each rifle will have its limitations, as does the ammunition used and the skill of the shooter.  Having information of past performance gives us a reference (baseline) to judge our errors and success against.  

The records we have available show that the average No. 4 rifle “as issued” shooting typical Mk 7 service  ammunition would not group within 2 MOA.  More like 4 to 6 MOA.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Goosic Quote  Post ReplyReply Direct Link To This Post Posted: September 01 2020 at 8:22am
Originally posted by britrifles britrifles wrote:

Having information of past performance gives us a reference (baseline) to judge our errors and success against.  

The records we have available show that the average No. 4 rifle “as issued” shooting typical Mk 7 service  ammunition would not group within 2 MOA.  More like 4 to 6 MOA.
The records we have available, "as issued", 4 to 6 MOA. Those being the key words. As issued service ammunition is no longer being produced nor is the rifle itself and the records only give a what was standard that existed 75 - 100 years ago. 
Change recorded history to reflect what the rifle is capable of doing now with various handloads and stocking up techniques.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Shamu Quote  Post ReplyReply Direct Link To This Post Posted: September 01 2020 at 9:10am
Well, perhaps if you'd mentioned the sizes I could have told you that. There is an upper limit but thats not what you complained about.

Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote The Armourer Quote  Post ReplyReply Direct Link To This Post Posted: September 01 2020 at 10:59am
Originally posted by Shamu Shamu wrote:

Well, perhaps if you'd mentioned the sizes I could have told you that. There is an upper limit but thats not what you complained about.


No need to get Narky.

I thanked you for explaining how to post PDfs, as I was not aware of the 'clamped box'.

I have posted big PDfs on other forums so never gave it a thought.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: September 01 2020 at 1:02pm
Originally posted by Goosic Goosic wrote:

Originally posted by britrifles britrifles wrote:

Having information of past performance gives us a reference (baseline) to judge our errors and success against.  

The records we have available show that the average No. 4 rifle “as issued” shooting typical Mk 7 service  ammunition would not group within 2 MOA.  More like 4 to 6 MOA.
The records we have available, "as issued", 4 to 6 MOA. Those being the key words. As issued service ammunition is no longer being produced nor is the rifle itself and the records only give a what was standard that existed 75 - 100 years ago. 
Change recorded history to reflect what the rifle is capable of doing now with various handloads and stocking up techniques.  

I would not want to change recorded history.   But, I do encourage the efforts many (including you Goosic) have made to get these rifles to shoot to their full potential.  To me, this record is important to those who buy their first LE, and wonder why they can’t get 1 inch groups at 100 yards shooting factory ammunition.  When the rifle was new it would not shot that accurate.  

It takes much work to get a LE to shoot that well, I’ve only had a few 10 shot groups that were within 1 inch, these were with a scope fitted.  Very good barrel and forend bedding being most important.  4 inch groups at 200 is about the best I have done with aperture sights, a bit better if shot off the bench.  

I’m assuming that Rogers statements in his video about accuracy reflects the potential accuracy that can be achieved with a good barrel, forend bedding, trigger lightening, scope, shooting off the bench, and match handloads to get to 1.5 MOA group size with the No. 4.  We are all tempted to show our best group (which may be sub-MOA) but it’s not the norm, not for me anyway.  

I don’t think the rifle “was designed” for this level of accuracy.  It’s a service rifle, there would be no need for this level of accuracy.  That implies a design requirement was established and verified by testing.   If that is true, I’ve never seen any documentation on it.  


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