Throating and free bore

Methow Packer · Aug 16, 2017

I'm building a rifle and want advise on how to determine the right throat dimension for my chamber. Would you choose the shortest bullet you may use and place the seating depth just past the boat tail. Then that would be the throat length?
Then any bullet I'd use longer would be seated deeper only because of its length. Example might be a 30 cal 190 ABLR is the shortest so the throat would be set to that length? Any longer bullet say 200 or 212 ELD-X would have to be seated deeper. I imagine you wouldn't want to throat your chamber using the longest bullet you might use. Please help me understand what length of the throat would be best

dfanonymous · Aug 16, 2017

I suppose its a matter of opinion. I like longer throats. I like increasing my seating depth and with a remington throat, which is usually a little bigger than most, i can easily seat bullets with longer bearing surface longer than mag length if i want. I suppose you are wondering more of freebore vs accuracy?

elkaholic · Aug 17, 2017

Methow Packer said:
I'm building a rifle and want advise on how to determine the right throat dimension for my chamber. Would you choose the shortest bullet you may use and place the seating depth just past the boat tail. Then that would be the throat length?
Then any bullet I'd use longer would be seated deeper only because of its length. Example might be a 30 cal 190 ABLR is the shortest so the throat would be set to that length? Any longer bullet say 200 or 212 ELD-X would have to be seated deeper. I imagine you wouldn't want to throat your chamber using the longest bullet you might use. Please help me understand what length of the throat would be best

I do just the opposite providing you are not making the coal too long to fit in your magazine, if that is a concern to you. Some people go long anyway and just single feed because performance is their main objective. The reason you throat for the longest bullet is because your over all performance is better. When you seat a bullet into the case farther, you are essentially lowering your useable case capacity thus reducing velocity potential. Hope this helps......Rich

Greyfox · Aug 17, 2017

I start with my desired bullet style and weight for the cartridge, generally a .29-.32 G7 BC, heavy for caliber, boat tail style (ex. 140gr 6.5, 210gr 30 cal). I will throat so the seated bullet will be .010"-.020" from touching the lands when the jumction of the bullet body(caliber),and boat tail of the bullet is at the base of the case neck. This dimension assumes the bullet will fit in the rifles magazine. It also provides for maximum powder capacity and some room to chase the lands if necessary.

Methow Packer · Aug 17, 2017

Greyfox said:
I start with my desired bullet style and weight for the cartridge, generally a .29-.32 G7 BC, heavy for caliber, boat tail style (ex. 140gr 6.5, 210gr 30 cal). I will throat so the seated bullet will be .010"-.020" from touching the lands when the jumction of the bullet body(caliber),and boat tail of the bullet is at the base of the case neck. This dimension assumes the bullet will fit in the rifles magazine. It also provides for maximum powder capacity and some room to chase the lands if necessary.

Thank You for your response. Your answer was very clear and what I was looking for. My mission is to shoot high BC bullets out as far as the throat and the magazine will allow.

jsthntn247 · Aug 17, 2017

Methow Packer said:
Thank You for your response. Your answer was very clear and what I was looking for. My mission is to shoot high BC bullets out as far as the throat and the magazine will allow.

What cartridge?

Methow Packer · Aug 18, 2017

jsthntn247 said:
What cartridge?

30 Nosler in a blue printed M70long action with a #4 Brux 26" fluted barrel and Vais break

L.Sherm · Aug 18, 2017

Your gonna need .180-.200 freebore for the 210-215 bergers. You shouldn't have any problem in a 3.7 mag box.

Throating and free bore

Methow Packer

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dfanonymous

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elkaholic

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Greyfox

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Methow Packer

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jsthntn247

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Methow Packer

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L.Sherm

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