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  #1  
Old 09-20-2018, 08:30 PM
ct kid ct kid is offline
 
Join Date: Feb 2010
Posts: 64
Default left bolt lug broke off today

bought a 308 rebarrelled m1 garand a few years ago. All is good until today. shooting the same ammo as with the couple 308 win m1 garands that I have. All shoot very well and 100% function and accuracy is very good.. So I know it's not the ammo.
Load an en-bloc pull back the op-rod let it go. as always. 2/3rds down the bot doesn't go all the way. Wow. All my garands have always functioned.
Upon looking the left lug was broken off . It's on the shooting bench.
Stopped right away.
What do I do besides getting a new bolt.
Question..... I would like to send the bot to someone for inspection. Who......
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  #2  
Old 09-20-2018, 08:45 PM
Jeremy2171 Jeremy2171 is online now
 
Join Date: Feb 2010
Posts: 924
Default

They break ..it happens...

nothing to really dwell on...new bolt..verify headspace and possibly lap the lugs if not getting good contact.

After shooting ARs for over 30 years I had my first broken bolt lug...replaced and moved on...

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  #3  
Old 09-20-2018, 08:48 PM
ct kid ct kid is offline
 
Join Date: Feb 2010
Posts: 64
Default danke

Danke.

Last edited by ct kid; 09-20-2018 at 08:49 PM. Reason: wrong key
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  #4  
Old 09-20-2018, 08:55 PM
me109g4 me109g4 is offline
 
Join Date: May 2010
Location: NH
Posts: 194
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Just out of curiousity could you tell us the heat lot and revision number?? thanks.
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  #5  
Old 09-20-2018, 09:03 PM
Old Guard Old Guard is offline
 
Join Date: Apr 2013
Location: tn
Posts: 783
Default Garand bolt failure chances.

Quote:
Originally Posted by Jeremy2171 View Post
They break ..it happens...

nothing to really dwell on...new bolt..verify headspace and possibly lap the lugs if not getting good contact.

After shooting ARs for over 30 years I had my first broken bolt lug...replaced and moved on...

very good advice on bolt..You can examine the bolt crack yourself. its dull colored edge will be the fault part of the crack, the brighter fresh look on the edge will show what was holding until the breakage..There was several warnings to check rifle bolts carefully. These rifles are all getting old..Now you can still buy new unused Garand bolts too. On subject of Ar bolts, my son just had all the locking lugs break off his generic rifle bolt..He was firing Tula ammo at the time, did not ruin the rifle this time.Now he has MPI marked bolt in it, I told him to watch his ammo for signs of overpressure.
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  #6  
Old 09-20-2018, 09:12 PM
ct kid ct kid is offline
 
Join Date: Feb 2010
Posts: 64
Default bolt lug

Looks like 6528287 HRA. Under the first markings The letter U
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  #7  
Old 09-20-2018, 09:16 PM
me109g4 me109g4 is offline
 
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Location: NH
Posts: 194
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Thanks,,, not the one I was expecting though. Never heard of an HRA bolt failing like that, must be a fluke. Regards, jeff T
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  #8  
Old 09-20-2018, 09:19 PM
Old Guard Old Guard is offline
 
Join Date: Apr 2013
Location: tn
Posts: 783
Default Ammo type and info

OP, what ammo did you have stashed? Curious about it ?
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  #9  
Old 10-20-2018, 08:09 PM
IRON WORKER IRON WORKER is offline
 
Join Date: Oct 2015
Location: USA
Posts: 61
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ct kid sent me his bolt a while back and I recently had time to inpsect it .The bolt is a HRA .U. UNDERWOOD made bolt .Mechanically the bolt was perfect all critical areas well within tolerances.

The surface hardness was at max spec of 61 HRC but core was near dead soft at 15 HRC . The issue is the case depth is over three times specified thickness around .060'' thick . This coupled with max hardness and left lug had most contact caused this bolt to fail.

Never seen this before or read any reports of such an issue but no doubt since bolts were done in lots there are more of these out there.Underwood had issues with M1 Carbine bolts I have seen.

If you use one in a shooter for saftey inspect it in good light with mag glass and check lug contact for safety reasons .

I surface ground the broken left lug and etched it with pottery grade media to show the contrast of soft core and hard case .You can see how thick the case is.You can also see the second crack in the face beside fractured area,has embedded brass in it.

https://i.imgur.com/rqkiVh0.jpg
https://i.imgur.com/9IKKkkL.jpg
https://i.imgur.com/kGIXWgt.jpg
https://i.imgur.com/jMQmVx0.jpg
https://i.imgur.com/u4Rxtt5.jpg
https://i.imgur.com/W2sg9Wr.jpg
https://i.imgur.com/wDI8DQx.jpg
https://i.imgur.com/yGVkGGW.jpg
https://i.imgur.com/G4HT4ZW.jpg
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  #10  
Old 10-20-2018, 08:18 PM
gunny gunny is offline
 
Join Date: Apr 2010
Location: North Bama
Posts: 6,245
Default

Wow! NICE "autopsy" report by an expert.

Quote:
Originally Posted by IRON WORKER View Post
ct kid sent me his bolt a while back and I recently had time to inpsect it .The bolt is a HRA .U. UNDERWOOD made bolt .Mechanically the bolt was perfect all critical areas well within tolerances.

The surface hardness was at max spec of 61 HRC but core was near dead soft at 15 HRC . The issue is the case depth is over three times specified thickness around .060'' thick . This coupled with max hardness and left lug had most contact caused this bolt to fail.

Never seen this before or read any reports of such an issue but no doubt since bolts were done in lots there are more of these out there.Underwood had issues with M1 Carbine bolts I have seen.

If you use one in a shooter for saftey inspect it in good light with mag glass and check lug contact for safety reasons .

I surface ground the broken left lug and etched it with pottery grade media to show the contrast of soft core and hard case .You can see how thick the case is.You can also see the second crack in the face beside fractured area,has embedded brass in it.

https://i.imgur.com/rqkiVh0.jpg
https://i.imgur.com/9IKKkkL.jpg
https://i.imgur.com/kGIXWgt.jpg
https://i.imgur.com/jMQmVx0.jpg
https://i.imgur.com/u4Rxtt5.jpg
https://i.imgur.com/W2sg9Wr.jpg
https://i.imgur.com/wDI8DQx.jpg
https://i.imgur.com/yGVkGGW.jpg
https://i.imgur.com/G4HT4ZW.jpg
__________________
Semper Fi,
Gunny
RVN '66 - '68 1st Tank Bn
USMC Ret. 1986, US Army Civilian Retired 2011

"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf."
-- George Orwell
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