Chasing accuracy problems in AR build

Talk about the AR15 style rifles chambered in 450 Bushmaster.

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Re: Chasing accuracy problems in AR build

Postby carpenterminator » Tue Jul 28, 2020 6:09 pm

See what you guys think for an essentially new barrel:
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Re: Chasing accuracy problems in AR build

Postby Hoot » Wed Jul 29, 2020 1:01 am

I've seen worse tooling marks. Those look about average depending upon how many rounds have already gone down that barrel. A proper lapping will clean those right up but first refresh me. Approximately how many rounds have gone down that tube? it may just not be broken in yet.You can treat it with some of those fire lapping bullets kits.

This is important: I've seen bores with worse marks still produce reliable small groups.

Their only issue was how often do you want to be cleaning them? I clean at the end of every range session while the barrel is still warm but that's more for the usual crud produced. I treat for copper buildup in my shop, where I can scope them and only clean as long as it take to get the copper out, with JB compound. That's not lapping, that's aggressive cleaning. Lapping involves either silicon carbide or diamond powder grit, suspended in a carrier oil and using laps that were cast to match the bore's rifling. Once neglected buildup is removed, then I only need to patch out the small amounts with KG12 copper remover. Note: Not recommended in chrome line bores.

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Re: Chasing accuracy problems in AR build

Postby carpenterminator » Wed Jul 29, 2020 5:49 pm

Thanks Hoot, This probably has 3 boxes through it.

I had convinced myself that the old break-in rain dance was baloney: fire three shots, clean thoroughly with bore solvent and brush, then two shots while chewing gum, then clean with snake oil... I used to do it.

Maybe there's something to it. Christiansen Arms recommends the raindance. I have old Winchester and Ruger rifles that I bought in the 80s and 90s with extensive visible machining marks (to this day!), but new Tikka and CZ barrels are like glass.

I expected better, but maybe Saturn isn't the brand that I thought. I would have paid more (I thought I was).
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Re: Chasing accuracy problems in AR build

Postby Al in Mi » Thu Jul 30, 2020 4:18 am

I have a couple Satern barrels and have worked with 3 others in 450, none have looked like that.

I'd give them a call.
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Re: Chasing accuracy problems in AR build

Postby plant_one » Thu Jul 30, 2020 10:42 am

Al in Mi wrote:I have a couple Satern barrels and have worked with 3 others in 450, none have looked like that.

I'd give them a call.



ya.. i would def send that picture to them - give em a ring, explain what you're finding and be like "hey whats your email. i have to send you a picture so you can see this" and drop it to them while you're talking to em.
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Re: Chasing accuracy problems in AR build

Postby carpenterminator » Sun Aug 02, 2020 8:37 am

Thanks for the advise, fellas, I'm [finally] going to give them a call. I've been avoiding that because I suspect that they'd just send me a new barrel, and I'd hate to start over.
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