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Discussion Starter · #1 ·
Where can I find a general set of M14 dimensions that can be used to evaluate an after-market receiver. With all the discussions about out of spec dimensions, it would be handy to have a list of important dimensions that could affect general operation and accuracy.

Thanks,

Art
 

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Reference Manual M14 and M1A

A great book for your library Jerry Kuhnhausen The U.S. .30 Caliber Gas Operated Service Rifles A Shop Manual Vol 1&11. A bit weighty but a good source of information in helping to sort things out. Lots of pictures with explanations telling what you are looking at or should be seeing. I'm always going to it clarify questions that I'm looking answers for. I brought 5 books on the M14 and M1A to help me learn after a bad experience with a dealer on an M1A. Every day is a school day learn from both the teacher and books. Good parts are spendy, but mistakes can even be more costly. There are wolves that are looking for sheep to pry on. A person can be measured by the friends,company he keeps and the books he reads and shares. This M14/M1A world is small and the interest is growing rapidly ask ???s. Those who share we be happy to and refer you to others to help. I know I brought parts from a guy on the East Coast and helped him on project he was going to tackle in my line of work. Its not networking its watching each others back.
 

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You can find drawings online simply by googeling m14 reciever prints. The drawings are complex, due to the fact of the part having so many dimensions in a relatively small area. I'm not sure if this helps, but its a start.
 

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Wouldn't it be wonderful if M14 clone receivers were of the original dimensions, and all parts for that matter also. Wouldn't it be wonderful if all parts were interchangeable. As of present, what receiver is the closest to orginal dimensions?. I remember somewhere that the Polytech Chinese receivers were. Is this still true or have new receivers come out that are closer. I realize that without getting into forbidden areas, that this discussion can only go so far.
 

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Discussion Starter · #5 ·
Receiver Dimensions

Thanks for the Replies. A copy of the Jerry Kuhnhausen book is in order.

I understand the complexity of measuring all the M14 receiver dimensions, but a list of "Most Critical Dimensions" would be a handy reference tool when evaluating a possible new purchase. I thought about this after reading the threads about stock fitting and scope mounting problems.

Art
 

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And this is a very good idea Art .....but oddly enough, the receivers most critical dimensions are not marked as would be the case in most blueprints. For instance, the left receiver lug is of prime importance for location, in relation to the bolt lug,....and the blueprint has every measurement under the sun, except that one. Once all the other cuts are made, per the drawings, then, thats whats left over. It is what it is.....Same thing with the receiver bridge....oh it has notations about where it should be when it's finished, plus or minus....but it has no instruction saying, cut this cut here to make this bridge here....It is just whats left when all other cuts are properly made.....You really need a degree in advanced mathematics to extrapolate all the figures and find where you are on these...and where you been.

I gotta tell you guys,..we are not just dealing with genius here on this receiver design,...we are dealing with Alien Genius....John was an Alien.....no doubt about it for me...heh heh heh.....sending you a PM Art.....
 

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Wouldn't it be wonderful if M14 clone receivers were of the original dimensions, and all parts for that matter also. Wouldn't it be wonderful if all parts were interchangeable. As of present, what receiver is the closest to orginal dimensions?. I remember somewhere that the Polytech Chinese receivers were. Is this still true or have new receivers come out that are closer. I realize that without getting into forbidden areas, that this discussion can only go so far.
I've also long heard, from several sources that the Poly Tech M-14/S forged steel receivers are the closest to an actual US GI M-14 receiver when it comes to correct metallurgy, hardness and correct dimensions.

The M-14/S receivers are the closest choice available, when it comes to specs, outside of a real US GI M-14 receiver for M-14 buffs to use US GI parts, to build as close as possible example of a semi auto M-14 with a forged receiver.

7th
 

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Wow, those are the '86 drawings - I was not aware these were in the public domain.

That said, someone wanted a solid CAD model, and was quoted $10,000. I told him that was nonsense, I'd bang one together in 2 days as a favor ..... 2 weeks later, I was still working it. I think the SOBs who made these drawings were trying to mess with each other, seeing how well they could hide a dimension deep in the guts so you had to find three dimensions on three different views and do addition/subtraction to figure out something.
 

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Wow, those are the '86 drawings - I was not aware these were in the public domain.

That said, someone wanted a solid CAD model, and was quoted $10,000. I told him that was nonsense, I'd bang one together in 2 days as a favor ..... 2 weeks later, I was still working it. I think the SOBs who made these drawings were trying to mess with each other, seeing how well they could hide a dimension deep in the guts so you had to find three dimensions on three different views and do addition/subtraction to figure out something.
They were in the public domain the day they were drawn back in the 1950s....

Just like technical and field manuals they were never copyrighted, or regarded as protected intellectual property, however, like TMs and FMs, that does not mean they are distributed to the public, they were regarded as "Distribution is limited to U.S. Government agencies and their contractors; critical technology".
 

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Can anyone interpret the last three revisions for me?
If you want the rational behind the changes you'll need to get a copy of the engineering change order listed in the description block.

If you just want the document numbers, They are:

Rev V
ECP W55206_ dtd 85-12-23 [last digit illegible]
ECP W38S2072 dtd 83-11-15
NOR W4S2051 dtd 84-08-24

Rev U
NOR 8S2022 dtd 79-03-26

Rev T
ERR HQR 40681

[EER = Engineering Release Record, ECP = Engineering Change Proposal and NOR = Notice of Revision]
 

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I was just wondering what changed so late in production.
Well, Rev T changed the cognizant engineering activity from Rock Island, IL to ARDEC in Dover, NJ, as well minor changes to the markings. The revisions are supposed to be annotated by a circled revision letter next to the change, according to MIL-STD-100 and ASME Y14.

It is remarkable to note that all revisions since "N" were done after the M14 went out of production.

Rev U and V were probably just routine house-keeping.
 

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Don't know if it was in the revisions but last production TRW iliminated the .250 radius on the heel corners and the 10 degree relief along the front rail/ring corner. Both were present in the 1,330,000 range.After 1,500,000 ,gone
 

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Don't know if it was in the revisions but last production TRW iliminated the .250 radius on the heel corners and the 10 degree relief along the front rail/ring corner. Both were present in the 1,330,000 range.After 1,500,000 ,gone
Both of those features show up on Rev V. TRW probably just skipped those steps to simplify manufacturer, and if anyone complained just asked for a deviation waiver.

That S/N range was their last contract, and at the price they were charging, they weren't making much off the deal. Also, I am sure that all manufacturers knew there would not be any further contacts after 1963, due to the noises coming from the OSD.
 
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