6.5 Creedmoor proof barrel with factory 147 eldm

sniper79_98

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Nov 1, 2009
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6
I shot about two boxes of these things today. The groups measured about an inch. Some were touching but no group was much under .750. The 24” heavy contour proof barrel has a total of 50 rounds through it. Has anyone had a PR barrel take a few rounds to settle in? Is factory 147s a go to for this caliber? This is an AR10.
 

jkramlich

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Jun 5, 2020
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Short answer is yes. After following the break in procedure found on proofs website, I still found that every once in awhile I’d still have a flyer or two. Took my barrel(s) around 100 shots to fully break in. Although I am shooting on a bolt action platform, I don’t see why it wouldn’t be the same. If fir some reason it’s still acting up after 75-100 rounds, I’d get in contact with proofs team

-Jayden
 

GUNNER10

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Mar 10, 2005
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Short answer is yes. After following the break in procedure found on proofs website, I still found that every once in awhile I’d still have a flyer or two. Took my barrel(s) around 100 shots to fully break in. Although I am shooting on a bolt action platform, I don’t see why it wouldn’t be the same. If fir some reason it’s still acting up after 75-100 rounds, I’d get in contact with proofs team

-Jayden
Agree with this.

Also, each barrel has its own personality and what it likes, it may shoot better 143's. Give it a box or two to settle in, follow through on fundamentals and if there is no improve, give a different bullet a try.

I got lucky with my factory LMT barrel and it loves 140gr American gunner. I will eventually do some load development with 147's but for now, 140s rock
 
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sniper79_98

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Nov 1, 2009
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Thank y’all for the responses. I bedded the extension to the receiver with a thermal fit using a shim and loctite. It’s and M5e1 upper with a diamond trigger. Scope is an SWFA SS. I built three other ones (Lothar Walther, Ballistic advantage) that shoot quarter sized groups. Seeing 5 shots needing a silver dollar did not make me happy lol. I’ll keep shooting and see what happens.
 

jkramlich

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Jun 5, 2020
25
2
Thank y’all for the responses. I bedded the extension to the receiver with a thermal fit using a shim and loctite. It’s and M5e1 upper with a diamond trigger. Scope is an SWFA SS. I built three other ones (Lothar Walther, Ballistic advantage) that shoot quarter sized groups. Seeing 5 shots needing a silver dollar did not make me happy lol. I’ll keep shooting and see what happens.
Let us know if anything changes!
 

kmdn_crew

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Aug 16, 2018
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Sometimes it is trial and error in seeing what your rifle likes. Every barrel and setup can be a bit different. I would see what the 140 grain does and go from there. .75 out of a gas gun isnt terrible though.
 

runningbear

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Oct 26, 2013
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Every gasser in 6.5 CM that I have owned (3), liked lighter bullets for some reason. The 120/130 grain bullets always shot better than the 140gr and above. This is just my experience. YMMV.
P.s. the rifles were: LMT, GAP10, and a custom build by Oxgoad Arms
 

sniper79_98

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Nov 1, 2009
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That’s awesome information to hear, especially that little ps bit lol. I’m aware different guns like different loads and so on. Knowing that three really well made rifles like those mentioned preformed better with lighter loads makes me optimistic moving forward.
 
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sniper79_98

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Nov 1, 2009
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My Proof barrel like the 140s better than the 147. I shot five of them in under two minutes that I can cover with a beer bottle cap. I’m happier than I was lol.
 

The King

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  • Sep 17, 2004
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    I overlooked that regard. Thanks for bringing that up!
    Specifically, gas guns can cause flyers due to bolt carrier velocity in a few different ways:

    1. Bolt Bounce. The bolt unlocks some when it slams home due to inelastic collision with the barrel extension.
    2. Damage to bullets - the barrel extension chews up the projectile when its loaded into the chamber.
    3. Set-back/pull out - The cartridge is loaded with such enthusiasm that the COAL changes.

    Enhanced buffering systems help with all of these, like the JP VMOS bolt in large frame guns and the Surefire OBC in small frame guns.

    So much so, I had NEVER gotten Hornady Superformance 556 75 grains to shoot in a gas gun, and changing to the SF OBC massively reduced the groups from that ammo to excellent results.

    That said, try single loading for a few groups to see if this is likely.