Free bore for the 230 Berger

[Edd]

So given a bullet with a bering surface length of .549 and a neck length of .323 I would need to have a parallel freebore length of .1766 to seat the bullet with the base of the bering surface at the neck shoulder junction?

What angle do you use to calculate the distance from the case mouth to the beginning of the parallel freebore? I don't think I have ever seen that on a print just a dimension for the lead.

I was using .529" for the bullet bearing surface length so, if you change it to .549", you need to add .020" to my number.

The most common angle for the transition from the neck to the freebore is 45°. There are some that are different. I just did a 35 Whelen. It was 30°.

 

[cjuve]

His 30-338 print makes more since.

That was based off a dummy that I sent in

 

[cjuve]

This is a Manson reamer drawing.

What is the case capacity of that cartridge?

 

[cjuve]

I was using .529" for the bullet bearing surface length so, if you change it to .549", you need to add .020" to my number.

The most common angle for the transition from the neck to the freebore is 45°. There are some that are different. I just did a 35 Whelen. It was 30°.

Thanks!

 

[Edd]

Here is the official 300 Norma print.

 

[NEMTHunter]

What is the case capacity of that cartridge?

After fire forming it holds about 141 Grains of H-110 to the bottom of the neck. I have not tested it yet with water.

 

[coyotezapper]

I am in the process of getting a couple reamers drawn up and was wondering what everyone was using for free bore for the 230 berger hybrid targets. The calibers in question are 30-338 Norma improved 33 degree, 300 RUM, 30-338 Lapua imp. 40 degree. All of my measurements and calculations put the correct free bore at approx. .225-.230 depending on the neck length required. After dealing with short throated magnums before a little extra free bore does not bother me and is actually preferred. If anyone has any suggestions it would be appreciated.

Make up a dummy round and send it to a reamer maker and get a minimum spec reamer made to match your dummy round.

 

[L.Sherm]

He already did.