I earned my Distinguished Rifleman with an M1a, and shot it well before the AR15 took over the firing line.
Believe it or not, Garands were very hard to acquire until the CMP. The Gun Club President told me that back in the 60's, if you wanted a Garand, you had to go to Camp Perry and buy a National Match Model. And you got one. Civilians were using CMP M1903A3's in service rifle matches, and getting their clocks cleaned by Service rifle teams using NM Garands, and NM M14's. If you have ever shot a M1903A3, the elevation adjustments are mostly wishful thinking and not MOA. You can get a 100 yard zero, going to 200 yds should be 2 MOA, three hundred, the adjustment is 3 MOA more, and by the time you are at 500 or 600, the elevation on the rifle is so far off you are holding way below the bull. It is impossible to shoot accurately if you are aiming above the target. You can imagine, the 500 yard sight should be 8 MOA up from 300, and the 600 12 MOA. Any movement of the rear up and down on the rear sight is going to end up with 4 MOA change increments at long range. It was horrible. The Garand and M14 had MOA clicks, the NM versions half MOA. Only State Teams had NM M14's and could compete at a reasonable level with service rifle teams. The game was still rigged, the military issued NM ammunition for leg and service rifle matches, and you did not get sighters. Service members would check their data books, see they had fired that lot before, and set their sights accordingly. Only those who wanted to win complained, everyone else was happy for the free brass!
I got my one and only (at the time) Garand through the DCM. Had to do a lot of hoop jumping to get it, fingerprints, etc.
It was in the middle 1970's that the Devine TX Springfield Armory M1a's came out, and while it took time for production to catch up with demand, the M1a replaced the Garand on the firing line. Mostly due to the fact the Garand lost it match tune sooner. It is very hard to prove one way or another that a match Garand in tune is better or worse than a match M1a on target, also in tune.
Springfield Armory then, as now, used 8620 steel in their castings, which is the steel the US Army used in Garands and M14's. I asked Springfield Armory in their Pavilion at Camp Perry why they had not used a steel with better properties. Such as 4340. Even the Army was looking to replace 8620
MECHANICAL AND METALLURGICAL PROPERTIES OF CARBURIZED 8620H STEEL FOR MI4 RIFLE COMPONENTS
Nov 1961
Fatigue
The second important factor to consider in the service of bolts and receivers is their short cycle fatigue life (10,000 to 20,000 rounds).
Investigation of Case-Carburized 93l0H Steel for Small Arms Components
19 February 1965
( Author J. F. Panda, V. Strempek H. R. Erard, P.E)
A heat-treatment study was carried out on 9310H steel which had been proposed for carburized components for M14 rifles and for M60 machine guns. The 9310 alloy was selected as a tentative alternate for 8620H steel because of its predictable response to hardening in the desired section sizes and because of its favorable low-temperature toughness characteristics. The 9310 steel provides a wider latitude in heat-treatment practice because of its more uniform hardening characteristics. Toughness of the 9310 steel, based on the results of Charpy impact tests, was superior to that of 862GH and 8620H resulphurized steels, particularly at sub-zero temperatures. Test procedure is described, and results are discussed.
this is an interesting chart. It came from a blow up of a Winchester M14 receiver. Seems Winchester used 1330 steel on some M14 receivers, and those receivers split right at the locking surfaces!
Springfield Armory, Genesco IL, uses 8620 because it is what the Army used. There is a cult of the mil spec, and baby would have puked if SA used something different. The Chinese actually used better steels. A bud of mine had a Norinco M14 ion spectrum analyzed, and talked to me about the results. I don't remember the approximate composition, but we looked it up in Machinery's Handbook, and it was good tough stuff. Used on power equipment gears. Applications that would chew up 8620. The thing is 8620 was the the low cost minimum steel that would meet a 6000 round endurance requirement.
Springfield Armory Genesco made modifications the the M14 receiver, one of which is thickening the sidewalls. The M1a receiver is a heavier, stiffer receiver than the GI receiver.
Target shooters put a lot of rounds through their M1a's, use M1a appropriate loads, and you should be able to go through ten barrels before you have any locking lug or receiver issues. This is based on shooters who did rebarrel their M1a's ten times. I only shot out three barrels, but on two rifles. One high mileage shooter I know, had his receiver crack above the bolt release. SA replaced it for free, which is good customer service. I think this was the 168 Match. I should have taken a picture of the end flap. Just keep 150's at or around 2700 fps. Ditto for the Garand.