338 Norma Mag

[Mark L]

OK, search function didn't show up anything.

Building a 338 Norma Improved.

Since Lapua isn't releasing (from what I can tell) any brass, what is everyone using? Norma or Peterson? Pros/cons?

When researching Peterson, it seems they had a "first run" with .0580 at the web and then changed to .0583. Have they fixed this and if I order any do I need to verify "first run" or not?

Anyone care to share their load experience for somewhere to start. I have Retumbo and H1000.

 

[codyadams]

Suprised you got nothin here. Ill give you some, but its on a standard .338 NM.

I ended up at 86.5 grains H-1000, going right at 2700 fps. Got up to 90 grains before I saw any pressure, going 2850ish. This is a 28" carbon six tube and HBN coated 300 Bergers.

Retumbo was almost the same except I stopped at 92 grains, at 2850.

Keep in mind, HBN lets you add a little more powder generally. You having an AI chamber, should be alright around those max charges, I just wouldn't start there.

I use peterson brass, way better than norma. First shot fixes the whole .580 thing.

 

[Mark L]

Thanks Cody,

I went ahead and bought (60) rounds of the Norma PH 300gr factory ammo. That way I can go ahead and fire form while I'm waiting on my Whidden dies to come in. I'll start low and work up till I see pressure signs. From what I've been told by others with this chamber, they are around 99gr of R33.

Picture of the factory round beside the fire formed casing:

 

[X47guy]

Baldys gotta make everything difficult

 

[WeiserBucks]

I would certainly recommend getting better brass . Peterson is good, I'm not 100% sure but I would think you could neck up Lapua 300 Norma brass also .

 

[Mark L]

Baldys gotta make everything difficult

If it was easy, it wouldn't be as fun.....

 

[highdrum]

Only issue with peterson is the neck thickness is 16thou. Check ur neck diameter of the reamer. I know lapua and Bertram are closer to 14.5 thou leaving you a little more neck clearance. I have shot some peterson in a 300nm and I couldn't slip a bullet back into the neck of a fired case very easily. This will cause pressure signs sooner in load development.

 

[Westernhuntr]

One thing I noticed with Peterson brass is they state that it's not to be fireformed.
I heard of one guy having them split down the center in an improved chamber, might be worth looking into.
What's the capacity of the improved NM?

 

[sp6x6]

338nm retumbo 90,300 otm @ 2750 out of 26''.Shoot same load out of 2 rifles

 

[codyadams]

One thing I noticed with Peterson brass is they state that it's not to be fireformed.
I heard of one guy having them split down the center in an improved chamber, might be worth looking into.
What's the capacity of the improved NM?

They put that there simply to clear themselves of any legal obligation, not because the brass can't be sucessfully formed. I personally called Ben and talked to him about it before I purchased brass for my .260AI, and he said it's fine they just label that for legal reasons. I have had no issues forming it.