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7.62x51 Chamber drawing
Posted: Sun Jan 23, 2011 9:21 pm
by ovenpaa
Does anyone have a drawing for a standard NATO 7.62x51 chamber with dimensions in Pdf format, or a link to one please?
Re: 7.62x51 Chamber drawing
Posted: Sun Jan 23, 2011 9:25 pm
by dodgyrog
No answer to that I'm afraid but another question.
I reload 7,62 x 51 brass ( cos I'm cheap!). If one reloads said brass with .308 Win dies and using .308 bullets does the resulting cartridge get accurately described as a .308 or a 7,62 x 51?
And yes I do have a VERY good reason for asking.
Re: 7.62x51 Chamber drawing
Posted: Sun Jan 23, 2011 9:32 pm
by ovenpaa
Well given there is a very subtle difference between a .308 and a 7,62x51 chamber, if you fire it in a .308 it becomes .308 by shape. The issue is if it is head stamped 7.62x51 and you *only* have .308 on your ticket however a reasonable FEO should be ok with this as for intents and purposes they are the same thing (Yes I know....................!!!)
I shoot a '7mm Christel' and the brass is 300SAUM, Christel shoots a '22 Christel' and the brass is 6.5x47 Lap. Should we ever get stopped and pulled for it I will ask to speak with someone from the local FEO (Plus cross my fingers)
Re: 7.62x51 Chamber drawing
Posted: Mon Jan 24, 2011 12:06 am
by The Gun Pimp
It really is time someone sorted this one out!
It only goes to underline the total lack of knowledge of our regulators.
As a matter of interest - did your police force accept '22 Christel' and put it on your FAC?
If they did, brilliant! You could have any 22 calibre rifle because there are only four of us - to my knowledge who really know what it is.
If Christel wanted a 22BR barrel next time or a 22-250 - why would she need to bother changing her ticket?
Cheers
Vince
Re: 7.62x51 Chamber drawing
Posted: Mon Jan 24, 2011 7:38 am
by ovenpaa
Christel has 22 CHRISTEL on her ticket and I have 7mm CHRISTEL on mine. First one was harder as the FEO had to find someone who knew how to add it to the computer which took a couple of day. Apparently he added some more CHRISTEL variants whilst he was doing hers and mine took one phone call.
Easy when you know how/who :)
Re: 7.62x51 Chamber drawing
Posted: Mon Jan 24, 2011 9:16 am
by Sandgroper
Ovenpaa,
Is this what you are looking for?
http://www.thegunzone.com/30cal.html
Regarding yours and Christel's FAC,
BASC says
Q17. Self explanatory. List firearms currently in your possession. If this is an application for the initial grant of a certificate, the answer to this question should be "none". Please note that the first box asks for the calibre of firearm. It does not ask what cartridge it fires, so the correct answer would be, for example, .22 (it is helpful to say rimfire or centrefire since they are so different) or 6mm/.244 or 6.5mm/.256 or 7mm/.284 or 7.62mm/.30 etc. as
the case may be.
but the Police Guidence 2002 says
10.5 Applicants are required to enter the
calibre and type of firearm(s) to be purchased
or acquired. The information will need to be
specific and not cover a range of calibres or
a generic group such as .22 CF (centrefire).
I've filled forms under both formats - the mind boggles! :?
Re: 7.62x51 Chamber drawing
Posted: Mon Jan 24, 2011 9:54 am
by ovenpaa
Nope, I am after the physical dimension of the chamber itself, I have drawings for the .308 SAAMI specification chamber but not the 7.62x51
When we first decided on the 22 CHRISTEL I rang the FEO and explained the 'new' cartridge in that it was a 6.5x47 Lapua necked down and so on, what it was going to be used for and the design criteria (MoD 5.56mm range legal and capable of 1200 yards) Followed up with a letter explaining everything again. The firearms team manager really did push the boat out to get it on the police computer and seemed genuinely pleased to have helped with something unusual.
A few months later when I mentioned the 7mm CHRISTEL he said no problems as he had added a few already just in case...
Re: 7.62x51 Chamber drawing
Posted: Wed Jan 26, 2011 8:04 pm
by ovenpaa
Via another forum, linking to another forum...
NATO EPVAT testing of 7.62x51 ammunition now lists pressure in PSI rather than CUP. Maximum Service pressure is given as 60,190psi & Proof pressure as 75,275psi.
7.62 NATO
Shank 0.4670
Base Diameter 0.4725
Shoulder Diameter 0.4560
Neck-1 0.3460
Neck-2/Case Mouth 0.3460
Freebore Diameter 0.3110
Pilot Diameter 0.2990
Min. Chamber Length/Base-to-Case Mouth 2.0250
Base-to-Shoulder 1.3560
Neck Length 0.3200
Freebore Length 0.1500
Rim/Belt Thickness 0.2000
Shoulder Angle 20*
Throat 2.5*
