Crown damage. Anyone seen this before?

Discussion in 'Gunsmithing Forum' started by The Dog, Sep 28, 2020.

  1. The Dog

    The Dog New Member

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    Has anyone noticed this kind of damage to a crown before. Deer hunting rifle 2 years old with only a few hundred rounds through it. It looks like little cracks and chips off the crown.
     

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  2. primer1

    primer1 Well-Known Member Supporter

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    Interesting, not in a good way. Following this thread to learn. I expect someone to come along shortly that has experienced this already.

    Welcome to the forum. Find the introductions and tell us something about yourself. There are lots of knowledgable people here with a good sense of community.
     

  3. JTJ

    JTJ Well-Known Member Supporter

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    That is a very sharp edge on that crown. Get it re crowned with a taper.
     
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  4. The Dog

    The Dog New Member

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    I'm going to have to see if it is still under garantee.
     
  5. Nod

    Nod Well-Known Member

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    Doesn't look like it's ever been crowned.
     
  6. Sniper03

    Sniper03 Supporting Member Supporter

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    Dog who is the manufacturer of the Rifle. And when did you first notice that? Are they actual chips out of the edge of the crown and not powder carbon that has chipped? If they are actual chips and can not be brushed off. I think I would be giving them a call and Email or FAX with the pictures. Since you rifle is doing that and they are infact chips in the Crown. I will bet in that production run, your Barrel is not the only one having this issue!;)

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    Last edited: Sep 28, 2020
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  7. c3shooter

    c3shooter Administrator Staff Member Admin Moderator Lifetime Supporter

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    If that is your B14, those a good quality rifles, guaranteed 1 MOA or less- and yes, that definitely appears to be chipping. There may have been issues with the heat treatment on that barrel. It's words with the manufacturer I'd be having. I use an 11 degree taper on my taregt rifles, Bergara looks to use about a flat recessed crown. But that does not look good. Is the accuracy holding up?
     
  8. BullMoose429

    BullMoose429 Well-Known Member Supporter

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    Did this happen all of a sudden or is it possible that it came from the manufacturer like this and you just happened to have noticed it only recently? I agree with C3- this is definitely a heat treatment issue- my guess is that they didn’t get an even temperature along the whole barrel- thus those chips are from the wrong crystal structure making that area very brittle
     
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  9. Sierra 173

    Sierra 173 Active Member

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    Looks like chatter marks from some kind of drill mechanism that wasn't run at the proper speed. When you run a drill too fast you get gouge marks like that. If they were to try to buff out those marks it would throw off the tolerances too much. They need to replace that barrel for you.
     
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  10. BullMoose429

    BullMoose429 Well-Known Member Supporter

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    I can’t imagine that any QC department would let that out in that condition- I work in industrial manufacturing as an engineer and any good QC guy would ream the hell out of an engineer who didn’t scrap that barrel.
     
  11. jigs-n-fixture

    jigs-n-fixture Well-Known Member Lifetime Supporter

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    Looks like flame erosion to me. As the bullet leaves the bore, the hot gasses are eroding the metal along the sharp edge. Looks to me like there are primary points of erosion evenly spaced. Does the rifling match up?

    My guess is that you have a very “over volume of chamber for the bore” round you’re shooting.
     
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