Free bore for the 230 Berger

[Edd]

I don't have a finished reamer print yet just one that we were working with

Post that one.

 

[Jud96]

He wouldn't know all the numbers he has quoted if he didn't have a print of some kind.

It's not hard to figure out neck length and bearing surface length

 

[cjuve]

This is the one that we were working off of before I sent in my dummies, I thought that the freebore was to short. I realize that there will be a slight increase in length due to the additional freebore diameter and corresponding lead angle.

 

[L.Sherm]

On the print I have, case length is 2.502
To the neck shoulder junction 2.187
So neck length is .315
Bearing surface on a 230 Berger hybrid .529
.529-.315=.214 +.010 .225

 

[cjuve]

On the print I have, case length is 2.502
To the neck shoulder junction 2.187
So neck length is .315
Bearing surface on a 230 Berger hybrid .529
.529-.315=.214 +.010 .225

How is the accuracy with that reamer?
Do you have to use a false shoulder to fireform?

 

[L.Sherm]

Hes just getting started, he got some brass fire formed but that's about it. He works overseas on a month on month off it was really showing promise just fire forming. It's a 35 deg. Shoulder and the case is straightened a little to .570
Hes using Peterson brass, it's nice consistent brass.

 

[L.Sherm]

I'm not sure if hes using a false shoulder.

 

[cjuve]

Here are the other 2 prints that I got my intention were to set them all up with the 230 hybrid target seated so that the end of the boat tail to the neck shoulder junction.

 

[NEMTHunter]

How much room to you have in the magazine? Or is going to be a single shot.

 

[Edd]

This is the one that we were working off of before I sent in my dummies, I thought that the freebore was to short. I realize that there will be a slight increase in length due to the additional freebore diameter and corresponding lead angle.

Based on that drawing, the bullet contact point will be 2.708" from the bolt face. That means the freebore would be .1662".

 

[cjuve]

How much room to you have in the magazine? Or is going to be a single shot.

I can go to a COAL of 3.825

 

[cjuve]

How much room to you have in the magazine? Or is going to be a single shot.

3.825 with the Norma
3.990 with the RUM
3.850 with the Lapua

 

[NEMTHunter]

I can go to a COAL of 3.825

This is for the 30-338 Norma.
If you have the standard case length of 2.492, Then that means you should be able to go with a .280 free bore and have a COAL of about 3.63.

Thats only seating the bullet's bearing surface .250 into the neck.

 

[cjuve]

Based on that drawing, the bullet contact point will be 2.708" from the bolt face. That means the freebore would be .1662".

So you took into account the transition from the case mouth to the beginning of the parallel freebore, the length of the freebore, and the transition from the end of the parallel freebore to the point where the bullet will contact the rifling ie the length that it takes for the diameter in the throat to reduce from .3092 to .308?