300 Norma Mag (Standard Version)

[KH_Outdoors]

Currently have a 338 Norma (standard) and using Lapua Brass. I have noticed on the Norma that the case grows a little more than 30-35 degree cases. Especially on first firing. Maybe plan to trim every 4-5 firings after initial?

I shot the virgin brass after just expanding/chamfer/debur. Then trimmed everything to same length and have put 4 firings on the current lot since trimming without having to trim again. Not too bad

I don't mind trimming cases on occasion for the Norma. Being realistic we don't shoot big 300/338 Norma's hundreds of rounds at a time (at least I dont). So taking a few minutes to trim every few firings hasn't bothered me yet.

 

[COBrad]

I have 300 NMI improved in the vault waiting to be fired, mine's intended as a long range elk rifle with a 30" barrel. I ordered dies from Whidden including his hydro forming die. Planning to do initial load development with already formed and sized brass. Hoping to save a little barrel life this way. The last shell holders are scheduled to arrive today.

 

[7.62 Gunner]

Then I started seeing reports from basically all the NM about clickers after a few reloading. These were from the very best die manf sent 3x fired unsized cases. The issue was these cases needed a bit more base sizing I believe. It was Alex that had worked it out and tweaked numbers to make it all work and minimal sizing but no more clickers.

That's exactly right, I did some researching and the 300 NM reamers are designed for Norma brass which is .581 above the web.
Lapua brass is .583 above the web so with approx .002 spring back clickers are definitely gonna be an issue.
Since you can't size the base down below virgin diameter without cracking the die the fix is going with a reamer that gives .005 clearance for a .583 base if using Lapua brass.
Pretty much the same reamer issue plagues the 6.5 and 300 PRC as well.

 

[QuietTexan]

ordered dies from Whidden including his hydro forming die. Planning to do initial load development with already formed and sized brass

Have you hydroformed before? I know Whidden says you can overform and set the shoulder back some, but it's still not a fully formed case like having been shot once.

 

[tim_w]

Have you hydroformed before? I know Whidden says you can overform and set the shoulder back some, but it's still not a fully formed case like having been shot once.

Agree. There is no sizing die hydroformm or not unless its hitting around 45k psi that's going to give the dimensions of a fired case. A good reason to not try tuning a load until you have fired the cases under a medium load first.

 

[COBrad]

The hydro forming went just as described by you guys. Still have to fire form but I can get correct headspace. The rifle is shooting well with pretty consistent half moa 3-shot groups at 1320 yards in calm conditions.

 

[FEENIX]

I have 300 NMI improved in the vault waiting to be fired, mine's intended as a long range elk rifle with a 30" barrel. I ordered dies from Whidden including his hydro forming die. Planning to do initial load development with already formed and sized brass. Hoping to save a little barrel life this way. The last shell holders are scheduled to arrive today. View attachment 405245

Agree. There is no sizing die hydroformm or not unless its hitting around 45k psi that's going to give the dimensions of a fired case. A good reason to not try tuning a load until you have fired the cases under a medium load first.

I have John Whidden built me a custom set of dies, including a hydraulic forming die for my .30 LARA.

From L-R"
1. 8MM RM virgin brass
2. After a couple of whacks with the hydraulic forming die
3. After running through the sizing die
4. Fireformed off the chamber with normal load

 

[WeiserBucks]

Don't be afraid of Peterson brass, It's every bit as good as Lapua and generally more available. I've got a single case with 16 firings on it and primer pocket is still usable. It's been trimmed a few times but it would be #1 in the magazine tomorrow no problem.

 

[COBrad]

I have John Whidden built me a custom set of dies, including a hydraulic forming die for my .30 LARA.

View attachment 409252
From L-R"
1. 8MM RM virgin brass
2. After a couple of whacks with the hydraulic forming die
3. After running through the sizing die
4. Fireformed off the chamber with normal load

That case looks a lot like the .300 Jarrett I was shooting almost 30 years ago. 200 grain bullets at 3028 fps.

 

[FEENIX]

That case looks a lot like the .300 Jarrett I was shooting almost 30 years ago. 200 grain bullets at 3028 fps.

Yes, Sir, the .30 LARA (37.5-degree shoulder angle) is very close to the .300 Jarrett (35-degree shoulder angle), and some other minor dimension differences. I can shoot the .300 WBY and .300 Jarrett ammo (very pricey) in a pinch.

 

[Carey Farmer]

Don't see a lot of love for the .300 Lapua Magnum. Seems like it would be pretty easy - just neck down, run a full length sizing die to push the neck / shoulder junction back to 25 degree angle, and trim the neck. That will yield a case that's pretty close to .300 Norma Improved capacity I think, with fire-forming not required.

Am I missing something?

 

[WeiserBucks]

Don't see a lot of love for the .300 Lapua Magnum.

Am I missing something?

Length and magazine compatibility are the one drawback if we're disregarding barrel life.

 

[Carey Farmer]

Length and magazine compatibility are the one drawback if we're disregarding barrel life.

Got it.

My rifles have 3.850" magazines. 300 Lapua (with neck length same as 300 RUM) is about 0.170" shorter than 300 RUM, and fits pretty well in that length magazine.

 

[QuietTexan]

Am I missing something?

My answer was if I'm going through all those steps, why push back the case capacity instead of running it as a 30-338 LMI?

300 Lapua is Betamax and the 300 Norma is VHS. Basically the same thing and they both work, but one went mainstream and the other didn't.