The Firing Line Forums

Go Back   The Firing Line Forums > The Skunkworks > The Smithy

Reply
 
Thread Tools
Old June 6, 2012, 09:02 PM   #51
Slamfire
Senior Member
 
Join Date: May 27, 2007
Posts: 4,130
Thanks for the pictures.

Very interesting.

Grandpa's ammunition was not that hot, which is good, because the 30-06 slamfire rounds I have seen were blown much lower in the case, indicating higher pressure.

As a case comes back, at some point the sidewall is unable to contain the pressure. The ones I handled looked almost cut, very precise on the location, no ragged, irregular edges.

Looks your case just blew out full diameter with no evidence of case rupture. That would indicate very low pressures.

A gunsmith can bend the operating rod to track properly.

I would get a CMP receiver and have the rifle built around that receiver. I would get a new stock.
http://www.thecmp.org/Sales/m1garand.htm

The receiver heel fits tighter to the stock heel section and it provides a gas barrier. If you notice there should be an air gap under the receiver ahead of the stock heel. This is a gas vent and protects the shooter in case of gas release in the action. Since your stock has a chip in that area, you really should just get a new tight fitting stock. Though someone could possibly fix the old, if there is no other damage. I would replace based on what I see.
__________________
If I'm not shooting, I'm reloading.
Slamfire is offline  
Old June 7, 2012, 01:29 PM   #52
James K
Staff
 
Join Date: March 17, 1999
Posts: 19,646
I have finally decided to point out why that was not a slamfire and to describe what actually happened. All I ask is that those with other ideas read what I write before sneering at my "stupidity", calling me names and questioning my ancestry.

First, the cartridge was heavily overloaded. (Even experienced reloaders can - and do - make mistakes.) Probably what was intended to be a light load was double charged, but in any event it was a serious overload.

The rifle fired normally, but pressure went sky high and only the strong M1 action prevented a blow up. The bullet went down the barrel at a high velocity, and as it passed the gas port, the gas, at a very high pressure port pressure, impinged on the operating rod, trying to push it back.

But the residual chamber pressure was still so high that the locking lugs were pressed tightly against the lug seats and did not move immediately. The op rod, under pressure at the front, and unable to move at the rear, bent.

Then, the bolt began to open and unlock. But the residual pressure was still high. Not enough to burst the case, but high enough to force the thinner case neck and shoulder out against the chamber wall as the case moved back, accounting for what appears to be almost a straight case. I think if you look, you will find that the primer is smeared and that the case head is flattened, almost obliterating the head stamp.

That residual pressure drove the bolt back hard, so it struck the rear of the receiver and broke it.

That is what happened, not a slamfire; a true slamfire (firing out of battery) would have blown the case apart, released high pressure gas into the magazine well and action, blown apart the receiver sides and splintered the stock. Yes, there have been slamfires with the M1 rifle, but this was not one.

Jim
__________________
Jim K
James K is offline  
Old June 8, 2012, 04:34 AM   #53
1911Tuner
Senior Member
 
Join Date: May 17, 2004
Location: NC Piedmont/Foothills
Posts: 605
Cracked

I think Mr. K's description is spot on. I was on hand for a true out of battery/slam fire with an M1 several years ago. It was pretty ugly. The shooter was injured, but he got lucky.
__________________
If your front porch collapses and kills more than three dogs...You just might be a redneck
1911Tuner is offline  
Old June 8, 2012, 08:08 AM   #54
mapsjanhere
Senior Member
 
Join Date: August 6, 2009
Location: Albuquerque
Posts: 2,355
Good that you are writing that Jim; I was looking at the pictures and couldn't figure out how the op rod got bent in an out-of-battery situation where the barrel pressure would be low.
__________________
F 135 - the right choice
mapsjanhere is offline  
Old June 8, 2012, 02:39 PM   #55
Slamfire
Senior Member
 
Join Date: May 27, 2007
Posts: 4,130
I would be interested in seeing a picture of the case head and primer. Maybe the OP will post that.
__________________
If I'm not shooting, I'm reloading.
Slamfire is offline  
Old June 8, 2012, 09:07 PM   #56
bbman25
Member
 
Join Date: February 15, 2012
Location: PA
Posts: 35
slamfire- I can get a picture of it for tomorrow sometime.
bbman25 is offline  
Old June 10, 2012, 02:55 PM   #57
bbman25
Member
 
Join Date: February 15, 2012
Location: PA
Posts: 35
the case on the left is a normal one, the right is the one from the incident.
the primer has a much deeper indent in it, it is also slightly narrower than the normal one. sorry for the poor quality, cell phone cameras aren't all that great. Other than the deeper indent, nothing else appears to be abnormal.
Attached Images
File Type: jpg 0610021357.jpg (216.1 KB, 18 views)
bbman25 is offline  
Old June 10, 2012, 09:34 PM   #58
James K
Staff
 
Join Date: March 17, 1999
Posts: 19,646
That doesn't help much, just brass colored blurs. Any chance of getting better and closer pics?

Jim
__________________
Jim K
James K is offline  
Old June 11, 2012, 08:20 AM   #59
Slamfire
Senior Member
 
Join Date: May 27, 2007
Posts: 4,130
Thanks for the pictures.

Given the OP says:

Quote:
Other than the deeper indent, nothing else appears to be abnormal.
I doubt there will ever be enough resolution to resurrect the idea that this was an over pressure event.

These normal looking primers are what you see in out of battery slamfires. I don’t know why the primers have normal firing pin indentations, but they do. I have seen two, the second blew the back end of the receiver off the rifle.

When the physical evidence is different from the theory, the theory must be wrong.

The slamfire cases I picked up, they were ruptured/cut about half to 2/3 rds of the way, this case is not ruptured so I am of the opinion that the loads were light.



__________________
If I'm not shooting, I'm reloading.

Last edited by Slamfire; June 11, 2012 at 09:21 AM.
Slamfire is offline  
Old June 11, 2012, 09:46 AM   #60
g.willikers
Senior Member
 
Join Date: September 28, 2008
Posts: 5,264
As to the question of weld or don't weld,
One of the very best machinists and welders that I ever ran across had a saying,
"You can fix anything but a broken heart."
And he could.
Unfortunately the guy doing the welding might not be one of the best.
So, two questions should be asked.
Is the reward of saving an old shooter worth the risk?
And, do you feel lucky?
(Had to get that one in).
Personally, unless it was the last gun of its type on the planet, I'd park it.
__________________
Lock the doors, they're coming in the windows.
g.willikers is offline  
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 01:19 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2014 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent: thefiringline.com
Contact Us
Page generated in 0.09662 seconds with 10 queries