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  #31  
Old 08-07-2020, 08:12 PM
cplnorton cplnorton is offline
 
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Sorry I've been on vacation.

But a couple things to add. I sort of got looking back at the docs for the change from Single Heat Treat to Double Heat treat. Even though in the 20's they detail about 20 rifles blew up with the Navy and that is what led to the change. They detailed that they were not investigated but I got looking today and I realized they actually did investigate some. I'll post one, but it looks just like what I see later in the docs, they always point it as being caused by defective ammo. But it looks like to err on the side of caution they made the change to double heat treatment.

Here is a Dec 1917 faulty ammo doc and one of the main reasons double heat treatment was introduced.

https://imgur.com/q7m2JSs


Now this is the actual docs describing the change to double heat treatment. So this details what the actual process was for SA. I have the process for RIA and Nickel steel as well. But it's all pretty similar between the Armories. Note at the bottom that it keys in again that the receivers are entirely safe as long as they headspace and the ammo isn't defective. It's just the same re-ocurring theme over and over in the docs, that it's how they could potential respond to defective ammo.

https://imgur.com/B0ukMni


The other thing I want you to key in on on that doc. SA did not do a hardness test for the low numbers, but did check the High numbers on the hardness test. But it looks like SA wanted the high numbers receivers to be between 45 and 60.

This is a key point to me as the Marines dispute these numbers as being safe. In 1938 the Marines were having problems with men getting hurt on grenading high number receivers. So they investigated it. They state that between 20 and 45 is what they determined to be ideal hardness range of a receiver, and above 45 can be too hard and brittle and can detonate if the receiver comes under defective ammo.

This is why the Marines drilled the additional gas escape hole on all high numbers, as well as low numbers. When the Marines stated to investigat the high numbers they found many of the high numbers tested were actually not safe.

This is why I preach over and over, just because you have a high number does not mean it's automatically safe.

We have been condition that only low numbers can be too hard and brittle and this is not what I'm seeing in the docs.

Last edited by cplnorton; 08-07-2020 at 08:25 PM.
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  #32  
Old 08-08-2020, 09:44 AM
navyrifleman navyrifleman is offline
 
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Very interesting documents and studies regarding receiver failures due to defective ammo.

It might be of interest that receivers of all of the US Krag .30-40 rifles were made using the same single-heat treatment described in the letters and in the book referenced in my previous post. It would be interesting to know if any similar receiver failures were reported in Krag rifles.

Defective ammunition is something which can ruin any rifle. During the Vietnam war, a US intelligence agency intentionally over-loaded a number of cases of 7.62x39mm (AK-47 and SKS) rounds and placed these in Viet Cong ammo caches. The idea was for the enemy to blow themselves up when using this ammunition. I do not know what their success against the VC was with this scheme, but there were at least a few US soldiers injured in this manner when they came into possession of captured arms and ammunition.
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  #33  
Old 08-09-2020, 12:00 AM
Rock Rock is offline
 
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Quote:
Originally Posted by navyrifleman View Post

It might be of interest that receivers of all of the US Krag .30-40 rifles were made using the same single-heat treatment described in the letters and in the book referenced in my previous post. It would be interesting to know if any similar receiver failures were reported in Krag rifles.
Similar failures would not occur with the Krag receiver due to its receiver ring design. The 03 failures occurred when a large amount of high pressure gas, from blown case heads, was released into locking recesses inside the receiver ring. The Krag doesn't have locking recesses inside the receiver ring for expanding gas to act on. The rear locking Lee Enfields are also not susceptible to blown receiver rings; the Garand also.
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  #34  
Old 08-09-2020, 09:27 PM
jakhamr81 jakhamr81 is offline
 
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Quote:
Originally Posted by Rock View Post
Similar failures would not occur with the Krag receiver due to its receiver ring design. The 03 failures occurred when a large amount of high pressure gas, from blown case heads, was released into locking recesses inside the receiver ring. The Krag doesn't have locking recesses inside the receiver ring for expanding gas to act on. The rear locking Lee Enfields are also not susceptible to blown receiver rings; the Garand also.
Not to mention that it was shooting a black powder round, not more powerful smokeless powder.
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  #35  
Old 08-09-2020, 09:37 PM
Rock Rock is offline
 
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Quote:
Originally Posted by jakhamr81 View Post
Not to mention that it was shooting a black powder round, not more powerful smokeless powder.
45-70 used black. 30-40 was smokeless.
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  #36  
Old 08-09-2020, 09:59 PM
jakhamr81 jakhamr81 is offline
 
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Quote:
Originally Posted by Rock View Post
45-70 used black. 30-40 was smokeless.
You're right. I was thinking the 40 grains was black. I suppose that would render it several under powered.
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  #37  
Old 08-10-2020, 09:23 AM
navyrifleman navyrifleman is offline
 
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Here is some specific information regarding 1903 receiver failures, published by the NRA in 1959:

"... From 1917 to 1929 inclusive, records were kept of all accidents to receivers of (1903) Springfield rifles, and during that time of the 800,000 low-numbered Springfields there were 33 reported burst or about 1 in 24,000. Of the 285,000 Rock Island low-numbered receivers there were 24 reported burst or about 1 in 11,000.

There were nine cases of severe injuries; no one was killed, and in most cases there were no injuries or only minor ones...

... During all those years there was no reported case of any receiver burst or bolt broken in any of the rifles having serial numbers higher than Springfield 800,000 or Rock Island 285,507. (Note, these figures all refer to rifles in service using issue ammunition).

Springfield Armory investigated reheat-treating low-numbered receivers and officially reported that reheat-treating them would not guarantee safety. This was because failures were generally due to burnt steel from overheating while forging, and burnt steel cannot be restored by any known method short of remelting."

Source: NRA Illustrated and Indexed Questions and Answers Handbook (1959)

Last edited by navyrifleman; 08-10-2020 at 09:21 PM.
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