One gentleman I shoot with had six barrels on his Springfield Armory M1a, before the receiver cracked just above the magazine release. Assuming a 5000 round barrel life, at 0.50 cents a round, that is about $15,000 worth of ammunition. He duct taped the cracked piece in, and continued shooting. Eventually he sent the rifle to Springfield Armory and they replaced the receiver, for free!
Excellent service.
He is still shooting his rifle, has a sticker with the word “Phoenix” on the side of the stock. The finish is worn to the wood where he cheeks the rifle. This year he removed the glue from the rifle stock, and I did not recognize the thing.
The bolt, gas cylinder, trigger guard, flash suppessor, are all original. Last year the operating rod broke in the saddle area and has been replaced.
http://img.photobucket.com/albums/v479/SlamFire/EditedriflePhoenixDSCN2278.jpg
As for the military, well they have to sit down and think about how long a rifle will last. I have read information that the lifetime of the FN rifle was considered to be 20 years and 5000 rounds. At the end of 20 years or 5000 rounds it was considered acceptable to send the rifle to depot and have everything worn replaced. And that includes the receiver, if necessary.
There is data on the 03 Springfield, the August 1928 article in Army Ordnance on overhauling th 03 Springfield. Out of a 10,000 rifle lot, 90% of the barrels were replaced, 85% of the receivers, 25% of the bolts. There are a lot of little parts listed, and the high percentage of receivers replaced was due to the Army scrapping “low number” receivers.
All numbers based on the lifetime of an existing M1a receiver, or M14 receivers, are estimates. Someone asked a military Armorer and that person gave an estimate.
I talked to the USMC rifle team Armorers about their M14’s, and they would occasionally have a receiver crack behind the rear sight. The most common location was left rear. The USMC also double lugged their receivers. It is my recollection that in 1996, USMC shooter Julia Watson was on path to be high shooter during NRA week, after being high shooter during service rifle week, when her M14 receiver cracked and ruined her score.
M1/M14 receivers receive an impact blow from the bolt. Basically the rear heel is the recoil buffer. If the receiver material is going to fail, it will be on the rear sidewalls. I have no doubt that the supporting material for the left bolt lug was sized for an indefinate fatique life. The right bolt lug is supported by the length of the op rod track.
GI receivers were optimized to reduce weight. The weight goal for the 30 Cal lightweight was an unrealistic seven pounds. Well the weight had to come from somewhere. The LRB forged receiver follows the Government data spec, as close as can without being full auto. As you can see in this rear lugged LRB photo, the there is significant material removal from the right receiver side, and this follows the GI Contour. Springfield Armory added material to their receivers, as can be seen in the second photograph.
LRB
http://img.photobucket.com/albums/v...r Pictures/ReducedRailreceiverrightinside.jpg
SA receiver
http://img.photobucket.com/albums/v...tures/ReducedDSCN6762SAM1areceiverrightsi.jpg
Lou makes a fine receiver, this is not meant as a criticism of his receivers. The people who are buying his receivers want something as close to GI as possible, and he has to provide what the market wants. Springfield Armory made changes, and I think this was a change for the good.
What would have probably added to the service life of the M14 receiver would have been using a higher grade material. The M14 receiver was made from 8620, an easily machined material that just met requirements. This material was a National Emergency steel first used in WWII Garands, and was used because only trace amounts of the rare and strategic materials Chromium, Nickel and Molybdenum were needed to get acceptable properties. Because 8620 was “Mil spec”, and there are vocal fanatics who think “Mil Spec” cannot be improved, commercial receivers use 8620. However the commercial receivers would be stronger and undoubtedly have a longer lifetime if they were made from a better grade of material, such as 4140.
As it is, 8620 receivers will outlast most shooters, but what that life is, I don’t know. I can’t afford to run a lifetime test.
But no matter how long the design life was, the actual life of these rifles was very short. They were made for less than four years, removed from service, and Evil Clinton destroyed hundreds of thousands of new M14's at Anniston Army Depot. I was able to buy salvaged bolts, op rods, trigger mechanisms, from the CMP, that were essentially, factory new.
