Gunsmithing 338 LM neck

[Erthal]

Hi guys

Now that I have all parts together, its time to decide on what neck diameter will be used for my custom 338 LM on Stillers action with MCM A5 stock with CIP botton metal, Krieger or Bartlein barrel-dont remember, ( alls this purchased from bugholes, a nice guy) and a 'Fat Bastard" muzzle break.
As this is a almost unknow caliber to me, I need some help to choose the best neck diameter and FB for my rifle, who will be used only for paper punching and my goal is a more accurate rifle possible, and reliable function isnt to important( just in case a tight neck will disturb) Also, a good brass life is a plus.
The bullets are Sierra and Berger 300 grains.
So what is yours neck diameter on rifles for this purpose?

Excuse my bad english writing

 

[BLDTYLRY]

If you are handloading, make a round and measure the OD then add 0.002".

 

[Edds]

If you are handloading, make a round and measure the OD then add 0.002".

I think that is too tight. I would want .004" clearance at the front of the neck and .005 at the back of the neck.

 

[Bluejazz]

I would go with .004 clearance.

 

[Erthal]

Hi guys

To me too seems that only .002'' clearance is on tight side, as my PPC rifle has .003". But as I told, I need some help.

The gunsmith have a match reamer with .375" to .373" on the mouth, but this seemed to large, as I was thinking more on the .004" clearance .

But as I dont know what will be the neck dimensions with Lapua brass and Berger/Sierra bullet seated, maybe this reamer will be just fine.

Thanks

 

[Edds]

The CIP spec for the chamber neck is .3744 and .3720.

 

[Straight Shooter]

I'm having incredible success with the PTG Tac Match reamer using Lapua brass and Berger 300's. You would be hard pressed to improve on it.

 

[Edds]

I'm having incredible success with the PTG Tac Match reamer using Lapua brass and Berger 300's. You would be hard pressed to improve on it.

What is the neck diameter and free bore?

 

[Straight Shooter]

My loaded rounds measure .3680" to .3682" on the neck. 300 grain Berger. Lapua brass. Reamer print says .373" at the mouth so about .005" clearance. It works extremely well. My personal Stiller Tac 338 with a PacNor 5 groove shoots 5 shot groups in the mid to high 1's. In the next week or two watch for a couple more best effort 338LM's to be finished up. I stay way clear of the rifling to avoid pressure spikes. Let's the bullet get a good run into it before pressure can spike. ES numbers are rarely over 20 fps. RL-33 or Retumbo.

 

[stenger]

I run .372 it's. .004 clearance works great for me.

 

[Edds]

That print look a lot like the Crane Naval Service print #10150.

 

[Erthal]

As always, nothing like listen those who already have walked the same road.

Thanks