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Discussion Starter #1 (Edited)
Cracking barrels Updade w/ pictures




Need a little help figuring out way some of our 1911 barrels are cracking. Here's a little definision on what is happening.

The barrels are cracking in the middle of the feed ramp and moving either to the left side or right side of the lower lugs then forward. I don't have pic right now but will try and get one. These barrels have between 10,000 to 50,000 rounds.

All barrels lower lugs are contacting 100% on the the frame.
None of these barrel have had a squib round.
All Factory ammo.
All heavy useage.
All 45 Cal
Recoil spring replacement is questionable not extactly sure lets say around every 6000
All barrels are the same Nowlin
 

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A bit more information would help?
What brand of .45ACP?
Who made the barrel?
Last time the recoil spring was changed out?
Chief-7700
 

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They're hitting the frame bed either a little before or at the same time as they hit the vertical surface. But probably a little before.
 

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These are non ramp barrels yes?

The std procedure is for the barrel to impact the frame, the link pulls the barrel down but the link is not to take the "hit" of stopping the barrels rearward motion. If it does the link, slide stop, slide stop pin, or lower lug can fail.

Is there a rounding of the top barrel locking lugs? The gun fires and the case tends to hold the barrel up in lock up, the link PULLS the barrel down out of battery. if the link does not pull the barrel totally out of the top lugs the impact to the frame is Much higher than it would normally be.

Also when the gun is out of battery, how much room with the barrel pushed down into the barrel bed. IF there is not enough room say .010 the barrel can hit down on the bed and bounce back up into the top lugs and if the link is not perfect in timing you can get a sheer.

The picture of the boe tie cut is a great picture. the alternative is to relieve the lower half of the barrel impact lugs so the leverage is reduced. (leverage of the bottom of the feet hitting the frame.)

hope this helps
geo

www.egw-guns.com
 

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Discussion Starter #7
Thanks for the posts so far

I want to make it clear these barrel's are not shearing the lugs they are intact.

The frames do not have the bow tie relief cut, the lower lugs contact this area 100%

The unlocking and timing seem to be on par. No upper lug rounding. Just a big fracture from the chamber to mid way down the barrel.
 

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I have seen more "Broken" nowlin barrels than any other brand. Coincidence?

I am guessing these are Springfield Pro's?
 

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Ok
so lets asume metalurgy
the thinnest part of the barrel is the feed ramp, thus the most likely place to have a crack start.
the highest pressure is the chamber
the metal is too thick to crack through the lug so the crack goes around it.


do you know how hard the barrels are?
if you need, send me one and we can rockwell test it.

geo

www.egw-guns.com
 

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Discussion Starter #10
Bladeandbarrel said:
I have seen more "Broken" nowlin barrels than any other brand. Coincidence?

I am guessing these are Springfield Pro's?
I didn't want to bring up what make they are but you are correct.
 

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I have a Les Baer PII .45 and the barrel cracked as was described through the feed ramp and around the lugs at around 100,000 rounds. I sent the whole gun back to Baer and he did not (refused) to return the barrel and thought that I had fired a round behind a squib. Almost all the rounds were 165 pf mainly lead. I still don't know why mine cracked either.
 

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RE: Hardpuller's Post

With 100,000 down the tube that barrel did you fine. I have a older Les Baer gun with about 40,000 down the tube and I am going to rebarrel it sone.

Be safe all. Spence
 

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HI CJ,

Baer has a good relationship with Kart. This you will like as they are Chrome molly.

Some of the barrel makers I have spoken to of late are changing to 416R which they say (and you will know) uses 1/4 the sulfer of the std 416.

Is there a range in Heat Treat on 416 where the material is not as strong?
a middle range or something?

thank you
geo

www.egw-guns.com
 

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WOW thats some craaaaacck!
 

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Not saying anything here, but I saw a Glock barrel which failed just like that. Glock said it was an overcharged round or the pistol fired out of battery. They still replaced the barrel.

But, then, is was also 40 S&W caliber - way more pressure than the 45 ACP.
 

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4d5smith -

Have you contacted the Custom Shop about this? They're warrantied for life, as far as I know.
 
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