How to choose new barrel chamber specs.

1moredeer

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Jan 29, 2020
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Northeast TX
I’m in the planning stages of my first barrel replacement on a factory 700 adl stainless synthetic in 300 wm. The factory sporter barrel has about 80 rounds down it and really likes the old black and red box solid base Nosler 180’s. Accuracy is not the issue but the recoil has always been unpleasant. I’m leaning toward a threaded carbon barrel with a brake to keep the weight down and reduce recoil. I need to understand the custom chambering options. With the current questionable availability of bullets, how do you select one to base your chamber specs on? The “what if’s” have me at a standstill. If I spec out a chamber for weight, OAL, throat, freebore etc. of a particular bullet and then find out the accuracy is unacceptable or the bullets are unavailable , where do you go from there? What if I chose a twist rate to shoot the heavies but decide at some point to shoot some lighter bullets, will accuracy still be acceptable? I want to make an informed decision and understand the risks and rewards of these choices. Any help would be appreciated.
 

MagnumManiac

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Feb 25, 2008
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3,017
There are several options, the easier of the many is to go SAAMI which is long enough in the throat for the majority of the VLD type bullets 215gr and less.
The other option is the A191 chamber which has a throat already set-up for the 230gr Berger. It is also held back so the case only grows .010” instead of .020” in the shoulder.
If you run a 9” twist, you could use the245-250gr bullets, but speed in the WM will be an issue.
I limit my own to 230’s as max. Even then the speed is not great and the 210/215 class bullets shoot flatter. I also only run 10” twists.

Cheers.
 

shortgrass

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Mar 31, 2010
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Western Oklahoma
If recoil is an issue now, I'd not consider a carbon fiber wrapped barrel,,,, even with a brake. For your first custom aftermarket barrel I'd do a SAAMI chamber and I'd think about a 9" twist. That'll shoot 165g on up. In my mind 165g is the lightest weight bullet I'd load in a 300Win and 230s would be max. With the current ups and downs with component availability I'd stick with the SAAMI chamber as there appears to be no end in sight to the component shortages. Too many guys tend to over think when it comes to a build, these days. No 'special chamber' or barrel made by a top end barrel maker and chambered by the most popular 'smith can make up for poor marksmanship skills.
 

1moredeer

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Jan 29, 2020
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Northeast TX
My first inclination was to make it easy and stay with a SAAMI chamber and 10” twist but I don’t want to miss an opportunity to choose the best combination for bullet weights of 165 to 215. Flexibility in this limited availability bullet market is a necessity. The intended purpose is hunting deer, elk and maybe aoudad out to 700 yards. A bum shoulder and lots of walking make recoil reduction and portability top priorities behind accuracy. I appreciate the input.
 

shortgrass

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Mar 31, 2010
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Western Oklahoma
I’ve considered that. The factory barrel is approx .680 at the muzzle. I not sure that’s enough meat for a 5/8 threaded brake??? Maybe shorten the barrel it a bit??
It could be threaded 9/16-24 or for a metric 15mm. I make a few brakes in my shop and can thread them for whatever is called for. With the China virus slow down last year, I seem to have threaded more barrels and made more brakes than I did custom barrel jobs last year. Guys being careful with their $$$$$, and I don't blame them for that. "Improving" what they have instead of replacing. Hope this year is better!
 

1moredeer

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Northeast TX
“Improving what I have” may be the best way to go. Having work done is like eating potato chips, you can’t eat just one. I could have everything squared up while I have it apart and go ahead and upgrade the stock and the glass too. Thanks for the input gentlemen.
 

shortgrass

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Mar 31, 2010
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Western Oklahoma
If the barrel length of your rifle is 24" or longer there'd be no need to "have it apart", just the trigger and scope removed. Most lathes gunsmiths use can handle a 24" barrel through the head stock. While it is admirable to have the receiver face square, and the bolt face square, and a 'truely' flat recoil lug (Rem calls it a barrel bracket), the barrel may not headspace when screwed back on after these 'improvements'. The chamber might need to be cut deeper so the bolt will close on the "GO" gauge. The barrel bracket would be part in limbo. The bolt face and receiver ring face don't usually require much material removal, add having the barrel bracket ground or an aftermarket used and it gets more deeply involved. Unless you can do the work yourself, the cost would be prohibitive for a 'factory' barrel re-install. Truing, or 'squaring-up' is best when having a new. aftermarket barrel installed.
 

1moredeer

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Jan 29, 2020
Messages
110
Location
Northeast TX
I didn’t realize that the barrel could be threaded without complete disassembly. That sure would simplify this project. I really appreciate the advice.
 

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