Here's a post by Lee Emerson in response to the question "Differences in overall quality SA M1A of 1988 and M1A 2008? It sums up some of the info in his "M14 Rifle History and Development (by Lee Emerson)" that can be found on a sticky at the top of this forum as well as his website. Lee has personally answered questions for me and like glg20 said, he is an excellent person and probably the #1 fan of the M14. Here you go:Quote:
Originally Posted by general Ike
Post subject: Re: Differences in oveall quality SA M1A of 1988 and M1A 2008?
Posted: 20 Apr 2008 09:15
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Lee Emerson Moderator
Joined: 22 Nov 2001 20:00
Posts: 5564
Location: Las Vegas, NV, USA
The M1A receiver has never been an exact duplicate of the M14 receiver drawing. Aside from the lack of select fire features, Melvin Smith made some changes from the get go since it was going to be investment cast. There's been a number of subtle changes in the M1A receiver design throughout the years, and I love them all, but my favorite M1A receivers range from serial number range from serial number 020001 to 063000.
From the draft of the Third Edition of M14 Rifle History and Development:
"Once this equipment was set up in his shop, Melvin Smith designed improvements into the civilian version of the M14 receiver. These changes included increasing the thickness of the receiver bridge, changing the operating rod rail to better support the operating rod and prevent automatic fire, removal of small amounts of material for better clearance, and relocating the operating rod dismount notch. After some persuading by his friend, Edward M. "Ned" Hogan, Mr. Smith kept the receiver left side geometry the same as the USGI M14 even though it would add to the manufacturing cost."
and
"In January 1972, Valley Ordnance Co. performed sixty-three machining steps for each M1A receiver. Earlier receivers machined by Valley Ordnance Co. were given a lot of hand grinding and polishing by Melvin Smith. Specifically, these areas were: 1) the exterior heel corners on the sides 2) the flat surface aft of the operating rod channel 3) the top surface of the left receiver wall from the cartridge clip guide to the barrel ring 4) the vertical surface on the right side behind the cartridge clip guide all the way back including the windage knob ear 5) the left side of the barrel ring forward of the horizontal scope mount groove 6) the magazine well aft of the feed lips and 7) the top surface of the barrel ring after all machining operations that located off the barrel ring had been done. This cosmetic detailing is evident as late as M1A serial number 062857 but was no longer being done by serial number 064922. Note that the hand polishing served to enhance the aesthetic appearance but did not add to the functional ability of the M1A receiver. As Melvin Smith moved to semi-retirement the receiver surfaces noted above were finished by machine. For example, the magazine well on M1A receivers was cut and broached by machine tool after Mr. Smith purchased Hillside Manufacturing."
and
"Beginning in January 1973, the rear end of the M1A receiver bolt right lug slot, located under the rear sight base cover, was extended 0.080 " to the rear to prevent possible damage to the bolt roller. In March 1973, Melvin Smith stated that he would adjust his machine tools to remove less steel from the M1A receiver for all future production in order to strengthen the rear end of the receiver. The author examined M1A receiver serial numbers 000049, 002884, 030061, 042201, 052122, 057969 and 141555 to verify this. M1A receiver serial number 000049 has a maximum thickness of ¼ " at the heel rear wall centerline. M1A receiver 002884 has 5/16 " thickness at the same location. Receiver serial numbers 030061 and higher all have a full 3/8 " thickness at the receiver heel rear wall centerline. Additionally, there is noticeably more uncut steel in the bolt raceways aft of the cartridge clip guide in the receiver serial numbers 002884 and up."
and
"The M1A receiver design was further changed prior to serial number 010048 to include a small hemisphere on the outboard side of the rear sight pocket right ear for use of a ball bearing to engage a detent on a newly designed match windage knob. This windage knob allowed ½ minute of angle sight adjustments by allowing eight “clicks” per revolution of the knob. Original USGI NM sights used a more delicate fine thread on the windage knob and rear sight base to effect ½ minute windage adjustments with four “clicks” per revolution.
Hope this helps answer your questions, good luck with your search. did you find anything more about the local M1A you mentioned? :D
