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Marking Identification

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D.Murray View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote D.Murray Quote  Post ReplyReply Direct Link To This Post Topic: Marking Identification
    Posted: December 31 2021 at 4:35pm
he!!o,

Just looking for help identifying these markings on my dads 303. Thanks!

Dave


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Post Options Post Options   Thanks (0) Thanks(0)   Quote A square 10 Quote  Post ReplyReply Direct Link To This Post Posted: December 31 2021 at 6:29pm
the last photo indicates its a Short Magazine Lee Enfield mkIII* , appears to have been made at rofal ordnance factory ENFIELD , i cant read the date in the photo later redesignated a No 1 mkIII* 

the other photos indicate proof and inspection markings , oddly i dont see a serial number 
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D.Murray View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote D.Murray Quote  Post ReplyReply Direct Link To This Post Posted: December 31 2021 at 6:34pm
Awesome thanks - here is the number Y 4127?


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Whitbread Quote  Post ReplyReply Direct Link To This Post Posted: December 31 2021 at 8:10pm
2.22" cartridge length
15t is the pressure psi the barrel is tested under before being release to the non military market
GR means it was manufactured during reign of King George lV (4th) 1936-52 
The itsy bitsy little stamps are armourers personal stamps each time it went in for service or repair it would get stamped
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Post Options Post Options   Thanks (0) Thanks(0)   Quote D.Murray Quote  Post ReplyReply Direct Link To This Post Posted: January 01 2022 at 3:42am
I really appreciate the help! Thanks 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Whitbread Quote  Post ReplyReply Direct Link To This Post Posted: January 01 2022 at 3:53am
Take a look at the bolt. If the serial number is the same you have a matching set! 
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Zed View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Zed Quote  Post ReplyReply Direct Link To This Post Posted: January 01 2022 at 10:37am
Proof pressure is 18.5 tons per square inch.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Whitbread Quote  Post ReplyReply Direct Link To This Post Posted: January 01 2022 at 12:16pm
My bad... Wasn't wearing my glasses. 
Pressure test is 18.5tGeek
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Goosic Quote  Post ReplyReply Direct Link To This Post Posted: January 01 2022 at 6:24pm
Howdy from Phoenix Arizona Whitbread. 
Do you own any Enfield rifles and if so, can you share them with us?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: January 02 2022 at 3:35am
I don’t think the 18.5 tsi is the “proof” pressure, it is the maximum average pressure for cartridges suitable for use in the rifle.  The stamped markings were added when the rifle was sold out of service along with the maximum cartridge case length, 2.222 inches. 

From various sources, the Proof Pressure for the SMLE Mk III was 24 to 25 tsi.

The Mk VIII ball cartridge was loaded to a maximum average pressure of 19.5 tsi.  It never made sense to me why the LE’s sold out of service were marked with 18.5 tsi when the Mk 7 service round was loaded to a higher pressure.  








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Post Options Post Options   Thanks (0) Thanks(0)   Quote Goosic Quote  Post ReplyReply Direct Link To This Post Posted: January 02 2022 at 7:11am
Using just the, "British Long Ton @2240lbs",to reach the magical 45000 CUP number, the rifle would have needed to be Proofed @ 20.0 long tons, or more specifically, 20.0892857143 British Long Tons. 18.5 tons, again, just using the British Long Ton only nets you 41,440 CUP. For comparison purposes only. My Canadian Arsenal barrel is NP'd to 22.3 tons per □". That is calculated to 49,952 CUP using the British Long Ton whereas I have a bolthead with 20T stamped on it netting a mere 44,800 CUP using the same British Long Ton formula....

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Post Options Post Options   Thanks (1) Thanks(1)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: January 02 2022 at 7:49am
There is no direct consistent relationship between the British oiled cartridge Base Copper Crusher method and the CUP Radial Pressure Method.  The British system of pressure measurement gives a lower pressure value.  

CUP radial pressure method used in the US gives 10 to 15% higher reading for the same actual peak pressure.  That’s why we have had trouble relating the 18.5 tsi stamp on the barrel to the SAAMI CUP capability of the .303 British cartridge.  We have a post on this subject on the Enfield Forum. 

The .303 British Oiled Proof cartridge gave a maximum average pressure of 25 tsi (56,000 psi) with the Base Copper Crusher method, estimated to be equivalent to 62,600 CUP.  


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Goosic Quote  Post ReplyReply Direct Link To This Post Posted: January 02 2022 at 9:03am
Originally posted by britrifles britrifles wrote:

There is no direct consistent relationship between the British oiled cartridge Base Copper Crusher method and the CUP Radial Pressure Method.  The British system of pressure measurement gives a lower pressure value.  
CUP radial pressure method used in the US gives 10 to 15% higher reading for the same actual peak pressure.  That’s why we have had trouble relating the 18.5 tsi stamp on the barrel to the SAAMI CUP capability of the .303 British cartridge.  We have a post on this subject on the Enfield Forum. 
The .303 British Oiled Proof cartridge gave a maximum average pressure of 25 tsi (56,000 psi) with the Base Copper Crusher method, estimated to be equivalent to 62,600 CUP.  
The British Long Ton of 25.0 does net 56,000 PSI which is equal to 51,943 CUP. Whereas 62,600 CUP is equal to 78,014 PSI, using the British Long Ton of 27.9.
When you get down to the Long and Short of it, everyone/nobody is right and nobody/everyone is wrong when it comes to the numbers. We are told and have accepted that 45,000 CUP is our do not exceed number and anyone stupid enough to screw a .308/7.62mm barrel on their No4 action is playing with fire and will get burned. My apologies to the OP for going off on a tangent here...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Zed Quote  Post ReplyReply Direct Link To This Post Posted: January 02 2022 at 11:57am
OK, this is interesting.
I was under the impression that the BNP (Birmingham Nitro Proof) stamp adjacent to the 18.5 ton
indicated the test pressure. 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: January 02 2022 at 1:33pm
Zed, the mystery becomes a bit more clear once you realize how the British measured chamber pressure.  An interesting article in the April 1967 NRA American Rifleman magazine describes it.  

Mk VI Ball was loaded to 17.5 tons per square inch and various sources state Mk 7 ball cartridges were loaded to 18.5 to 19.5 tons per square inch.  This is using the British method of measuring base pressure exerted by the cartridge case itself, there was no pressure tap drilled into the barrel as used for the American CUP method of measuring pressure.  I believe the 18.5 tons per sq in markings on rifles sold out of service was conservatively based on the lower pressure levels for Mk 7 ammunition, to discourage use of Mk 8 ammunition perhaps.

The best I can tell is that 18.5 tsi conversion to CUP can be approximated by using a ratio of 1.1 of British Base pressure method to American Radial Pressure method (CUP).  18.5 x 2240 x 1.1 gives 45,584 CUP.  And that is pretty close to the SAAMI maximum average pressure of 45,000 CUP for the .303 British cartridge.  So, the 18.5 tsi is clearly not the proof pressure (Reynolds and others have stated the proof pressure cartridge exerts 25 tsi).  Note that there was never the intention to fire more than one oiled proof round, generating 25 tsi.  

The key to understand this is that the British method to measure pressure is entirely different to the radial pressure methods used by the US and Europe and are not directly related.   The base method actually measures the load, or force exerted on the breach by the cartridge.  The permanent strain (deflection) of the copper crusher inserted into the special breechblock is then related to pressure via a table correlating the amount of deflection to pressure in psi.  It is similar to CUP, but the conversion tables are not the same.  There is no direct linear relationship between the different measurement methods, and it is different for every cartridge due to its dimensions, body taper, etc. 


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Shamu Quote  Post ReplyReply Direct Link To This Post Posted: January 02 2022 at 3:24pm
It does, but not quite in the way you think!

It is NOT like a pressure gauge on a high pressure gas tank, (PSIG) but an extrapolated "triage table" relating the compression of a "pill", usually lead for low & copper for high pressures, by a piston, measuring the result then looking up the difference.
The "PSI" term has been misleading people & giving them the heebie-jeebies for ever.
Its not directly relatable either.

1,000 "PSI" is not double 500 "PSI" nor is it half of 2,000 PSI. There isn't even a direct linear compression to "PSI" from units of compression in thou, or whatever, either, you have to look up the individual table! even worse neither actually translate to Pizeo Transducer measurements!

Interesting (but heavy going) article on the subject.
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