Gunsmithing  Proof CF prefit barrel on Tikka T3x - Bolt Closes on no-go gauge but not on Field gauge

LANCER

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So I decided to install a Proof Carbon barrel on my T3x. Prior to install, I cerakoted both the action and the steel parts of the barrel. I did not tape off the action face nor the mating face of the extension, although I DID tape off the barrel threads. When I installed, I only had a go-gauge, and since the bolt closed on the go-gauge, I decided it was "good enough" like an idiot.
Few months later, I'm on my second firing of Lapua 308 brass in this chamber (but had 8 firings before in old factory barrel) and I had 3 case head separations on a mildly warm load.
Decided to buy No-Go and Field Gauges of the same brand just to make sure I wasn't having a headspace issue. They are Forster gauges.

The no-go gauge closes with slight bolt resistance.
Field gauge does NOT close.

I read that closing on a no-go is not necessarily terrible as long as it doesn't close on a field gauge. However it seems I have a "generous" headspace. Brass had previously been bump-sized and neck-sized after fireforming again in the new chamber. I've fired other ammo that I loaded for my semi-auto (LC LR brass) and of course did not have any issues. I have not measured my LC--LR brass which was new prior to firing.

Am I over thinking and my Lapua brass was simply shot out or had ICHS or is my headspace really that much off? Should I have a gunsmith turn a couple thou off my barrel to remove the cerakote so I can have tighter headspace? I want to make sure before I run new brass through this chamber. It shoots 1/3 MOA currently on my good days.
 
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Raufoss

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Nov 23, 2010
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Your fine, carry on and don’t worry.

A small DT said it’s better to start with new brass if you don’t want to experience some issues.
 
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JD. martin

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May 12, 2020
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Az
So I decided to install a Proof Carbon barrel on my T3x. Prior to install, I cerakoted both the action and the steel parts of the barrel. I did not tape off the action face nor the mating face of the extension, although I DID tape off the barrel threads. When I installed, I only had a go-gauge, and since the bolt closed on the go-gauge, I decided it was "good enough" like an idiot.
Few months later, I'm on my second firing of Lapua 308 brass in this chamber (but had 8 firings before in old factory barrel) and I had 3 case head separations on a mildly warm load.
Decided to buy No-Go and Field Gauges of the same brand just to make sure I wasn't having a headspace issue. They are Forster gauges.

The no-go gauge closes with slight bolt resistance.
Field gauge does NOT close.

I read that closing on a no-go is not necessarily terrible as long as it doesn't close on a field gauge. However it seems I have a "generous" headspace. Brass had previously been bump-sized and neck-sized after fireforming again in the new chamber. I've fired other ammo that I loaded for my semi-auto (LC LR brass) and of course did not have any issues. I have not measured my LC--LR brass which was new prior to firing.

Am I over thinking and my Lapua brass was simply shot out or had ICHS or is my headspace really that much off? Should I have a gunsmith turn a couple thou off my barrel to remove the cerakote so I can have tighter headspace? I want to make sure before I run new brass through this chamber. It shoots 1/3 MOA currently on my good days.
I have 390 rds on new 6.5CM Proof research carbon barrel installed by smith. I happen to just notice although I had Forster field Guage but no,go/No Go Guage’s so I did same bought go and No go Forster Guage’s and SAME PROBLEM!! Closes with little resistance
On no go but NOT FEILD GUAGE!! Man I was worried till I found you all and the ole boys saying “ CARRY ON”Thanks
Tremendously you all
 
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Shooter71

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Aug 25, 2013
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Your headspace is likely long, which isn’t a big deal if you’re setting your fl sizing die properly. If you don’t know exactly how much back you’re setting your shoulder, for that chamber, you need to.
 

JD. martin

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May 12, 2020
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Az
Your headspace is likely long, which isn’t a big deal if you’re setting your fl sizing die properly. If you don’t know exactly how much back you’re setting your shoulder, for that chamber, you need to.
Thanks MR!!! I appreciate your input Sir.
never thought to ask on here plenty
shooters that have FORGOTTEN MORE THAN ILL EVER KNOW. Even though been dabbling in long range for 8yrs now. Yea I bum shldr .020 thou with an average of 2.30,95” proof prefit in tikka
Tac A1. Thanks agin my freind
 

Shooter71

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Aug 25, 2013
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Did you mean .002”, instead of .020”? Might’ve been a typo. .002” would be appropriate, .020” would definitely lead to case stretching and separations. You probably know, but for anyone that might be reading, head separations can be pretty dangerous and potentially hurt you and the rifle. If your setup and brass control is good you’ll get loose pockets after a while, but not head separations.
 
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Mike Casselton

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  • Nov 25, 2007
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    Lithia, FL
    Thanks MR!!! I appreciate your input Sir.
    never thought to ask on here plenty
    shooters that have FORGOTTEN MORE THAN ILL EVER KNOW. Even though been dabbling in long range for 8yrs now. Yea I bum shldr .020 thou with an average of 2.30,95” proof prefit in tikka
    Tac A1. Thanks agin my freind

    Please, for the love of all that's holy, please use complete words and sentences.

    There's no reason to abbreviate that much if you want anyone to have a chance a understanding what you're trying to say.

    Thank you,
    Non-Management


    Also, yeah, I'm pretty sure you meant .002, not .020.
    Although, I've seen it done, the brass becomes 2-pc brass very quickly.
    Glad you got it sorted out.
     
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    JD. martin

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    May 12, 2020
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    Az
    Did you mean .002”, instead of .020”? Might’ve been a typo. .002” would be appropriate, .020” would definitely lead to case stretching and separations. You probably know, but for anyone that might be reading, head separations can be pretty dangerous and potentially hurt you and the rifle. If your setup and brass control is good you’ll get loose pockets after a while, but not head separations.
    Shooter71:
    Yes SIR!! Thanks most definitely typo on my part,nice catch. It’s .002” thou
    Not .020” thou. Have always run lapua brass so this barrel was no exception after second firing case growth has stopped not much of any trimming. Tube is averaging .371” to .405” as long as I’m doing my part!! Been happy with it. Thanks again MR. Shooter71: thanks for response and corrections. Have great day Brother. J. Martin
     

    JD. martin

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    May 12, 2020
    10
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    Az
    Please, for the love of all that's holy, please use complete words and sentences.

    There's no reason to abbreviate that much if you want anyone to have a chance a understanding what you're trying to say.

    Thank you,
    Non-Management


    Also, yeah, I'm pretty sure you meant .002, not .020.
    Although, I've seen it done, the brass becomes 2-pc brass very quickly.
    Glad you got it sorted out.
    Thousand pardons Sir, Never been very good at grammar/punctuation in any form of writing. Not sure this is correct
    Lmao. Hate typing txting the whole Ball, so always just half ass my writing more shooting. I’ll get ir fixed oops, Get it fixed. Thanks MR. Much appreciated
    J. Martin.
     

    Mike Casselton

    Non-Bidenary Trunk Monkey
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    Minuteman
  • Nov 25, 2007
    6,793
    10,251
    Lithia, FL
    JD,
    I wish more people on the Hide would take a good natured ribbing like you did.
    👍👍
    On a serious note though, lots of people ask questions and can't even form a proper sentence. Yours wasn't like that, just hard to follow with the texting style abbreviations.

    It's all good.
     
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    LeftyJason

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  • Mar 8, 2017
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    Just a heads up. "0.002" thou" is redundant. Pick one or the other. "2 thou" or "0.002" " works.

    -sincerely someone who regularly works in tenths (0.0001") or ten millionths (0.00001") increments.
     
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