.338 Norma improved worth it??

SPAK · Nov 19, 2012

Hey guys,
building a .338 norma and I'm about to order the reamer.
I've picked a few hide members' brains already but I wanted to get some other opinions on whether or not making a 30-35deg shoulder on a .338 norma mag would be worth the trouble?

Is there enough performcance gain to be had to make it worth custom dies and fire forming?

Is there any decrease in accuracy over the original design?
Any thoughts would be appreciated or real world experience with a .338 norma improved would be great.

Rifle will be a repeater built on a surgeon xl action with CIP length magazines.
Thanks in advance.

Skyking · Nov 19, 2012

Re: .338 Norma improved worth it??

I would definitely do it. I have a buddy that build one that I did all the fire-forming for. I don't remember the numbers but I was way impressed. You are really moving that should up a lot. It was a big difference. I can get you the numbers that he has.

SPAK · Nov 19, 2012

Re: .338 Norma improved worth it??

Sky king that would be really helpful... Who did he have make a full length sizing die from??

One of the reamer makers reccommended a 37 deg shoulder and said folks were getting another 2-3 grains more powder capacity, but I don't know what that translates to in terms of velocity or accuracy...any thoughts?? Someone over on longrangehunting.com seemed to think messing with the original shoulder angle would decrease accuracy, but other than the opinion is there any quantifiable truth to that??

SPAK · Nov 19, 2012

Re: .338 Norma improved worth it??

Also, how did you do he fire forming?? Bullets or COW method?

Bluejazz · Nov 19, 2012

Re: .338 Norma improved worth it??

Do the standard 338 Norma.
If you want to go AI do it on the Lapua case and blow out the body taper .
You get much more case capacity,and velocity, making it worth the trouble of fireforming.

Donald · Nov 20, 2012

Re: .338 Norma improved worth it??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bluejazz</div><div class="ubbcode-body">Do the standard 338 Norma.
If you want to go AI do it on the Lapua case and blow out the body taper .
You get much more case capacity,and velocity, making it worth the trouble of fireforming. </div></div>

Some good advise

SPAK · Nov 22, 2012

Re: .338 Norma improved worth it??

Thanks guys... I've had more input to stay with the standard norma...unless there's a reasonable gain of at least 100fps it's probably not worth it...

762 ULTRAMAGA · Dec 18, 2019

I'm reviving this post...
Finally set on a 338 Norma after considering a few other options.
Now I'm torn between the standard or improved, mainly I'm concerned that the 20 degree shoulder will cause lots of case stretching above the base.

I'd like to hear from you guys with experience with either version of the 338 NM over the years.

Steel head · Dec 19, 2019

I think the post above say it’s better to improve the lapua is spot on.
Not that a 338 Norma AI wouldn’t be cool.

I do the loading for my buddy’s 338 Norma.
case growth has been minimal, after 5
Firings it’s just about time to trim.
If your headspaced right so new brass isn’t abused on the first shot you’ll be fine like all the other wonderful 20 Degree shouldered cartridges.

762 ULTRAMAGA · Dec 19, 2019

Steel head said:
I think the post above say it’s better to improve the lapua is spot on.
Not that a 338 Norma AI wouldn’t be cool.

I do the loading for my buddy’s 338 Norma.
case growth has been minimal, after 5
Firings it’s just about time to trim.
If your headspaced right so new brass isn’t abused on the first shot you’ll be fine like all the other wonderful 20 Degree shouldered cartridges.

Thanks man that's helpful.
I'm not interested in going as big as the Lapua improved since this will be a packable hunting rifle with a 26" barrel, and weigh 10 lbs scoped.
If case trimming is only needed every 5 firings then I'll be happy
That's about what I average with 30 degree shouldered cases.

xdeano · Dec 19, 2019

I did the standard 338nm. If I were going to change the shoulder angle it would be a 30 degree. 30 is the most efficient funnel. But instead of trying to get extra velocity out of extra case capacity, just drop down bullet weight a bit and run solids, you'll make up the velocity. I shot the cutting edge 277grn mtac. They are fantastic. I'm assuming since you want it fairly light youll be hunting with this combo, then id run a cutting edge 275 lazer, or 275 mth.

Xdeano

762 ULTRAMAGA · Dec 19, 2019

xdeano said:
I did the standard 338nm. If I were going to change the shoulder angle it would be a 30 degree. 30 is the most efficient funnel. But instead of trying to get extra velocity out of extra case capacity, just drop down bullet weight a bit and run solids, you'll make up the velocity. I shot the cutting edge 277grn mtac. They are fantastic. I'm assuming since you want it fairly light youll be hunting with this combo, then id run a cutting edge 275 lazer, or 275 mth.

Xdeano

Totally
It's solely for LR elk hunting
I've shot my last two bulls at 940 and 680, the last bull I shot three times with shitty 215 Bergers and had two failures.
I'm going cutting edge or 265 ABLR's, no more target bullets for elk

762 ULTRAMAGA · Dec 19, 2019

What are you getting for velocity with the 275's and what's your barrel length?

xdeano · Dec 20, 2019

Westernhntr said:
What are you getting for velocity with the 275's and what's your barrel length?

My standard 338NM with 275-277grn cutting edge bullets are right at 2850fps. There seems to be a node right there. I can go hotter but I'm after accuracy. This is a 26" benchmark barrel, custom contour. Im using RL33, Norma brass and fed 215m primers, 0.020" off lands.

Xdeano

762 ULTRAMAGA · Dec 20, 2019

That's really good velocity.
I'll be using H1000 or Retumbo most likely, so I'm guessing it won't get me the speed you're seeing with RL33.
Ill also be shooting a 26" Benchmark.
Have you seen any temp sensitivity with RL33?

xdeano · Dec 21, 2019

Westernhntr said:
That's really good velocity.
I'll be using H1000 or Retumbo most likely, so I'm guessing it won't get me the speed you're seeing with RL33.
Ill also be shooting a 26" Benchmark.
Have you seen any temp sensitivity with RL33?

Rl33 has some temp sensitivity. You will find that h1000 and retumbo will get you very similar velocities, h1000 is very consistent. I use large quantities of h1000 in all my other guns from 22-243s on up. Its good stuff. Rl33 is good for velocity, and barrel wear. ?

Xdeano

BCX · Dec 31, 2019

I put together a Defiance Deviant, Proof 24 inch plus brake, Manners T-A Elite w CIP mini chassis in 338 LM AI for a packable hunting rifle. 285 ELD @ 3K FPS mag fed. Cant get you a weight yet...my Manners should be here this month.

WeiserBucks · Dec 31, 2019

Tagging in , I'm getting ready to decide on a standard or improved 338 Norma. Load data I've found is mostly H1000, Retumbo and RE33 , anyone had good results with N570 or RE26 ? I'd prefer H1000 but its unobtanium and seems like guys are getting great results with N570 in the 300 Norma but haven't seen any results in the 338 .

BCX · Dec 31, 2019

Im all about the improved case. My 40 degree shoulder feeds fine and gives nothing up in the accuracy department. 3/8 w Factory 338 LM Scenar and 1 hole w handloads. Plenty of factory 338 LM ammo to shoot in a pinch.

Steve_W · Feb 17, 2020

In a repeater, the advantage a 338 Norma Improved has over the .338 EDGE and .338 RUM is that one can easily run it in a 3.850" magazine with a 300 gr Berger and still use all of the available case capacity - with resulting velocities virtually equal to the longer cartridges. The EDGE and RUM require 4.0+" COAL when throated properly for the longer bullets.

For those interested, world-class 1K BR shooter Tom Mousel has started a discussion thread here on his current load development with the .338 Norma Mag Improved.

Swamplord · Feb 21, 2020

load development / barrel break in vid I did a few years ago with my version of a 338 MN Imp, 26" barreled repeater for hunting moose n bear in Alaska

Swamplord · Feb 21, 2020

maiden voyage for moose, Sept. 2017 , with the 325 gr Chinchaga RBTST bullets

Swamplord · Feb 21, 2020

Sept. 2018 with the 270 gr Badlands Super Bulldozer bullet

Swamplord · Feb 21, 2020

Swamplord · Feb 21, 2020

the first animal back in Sept 2017 (one week before the bull moose) was this black bear, the 338 PRO with the 325 gr Chinchaga bullet whacked him good at 530 yards

LongJohn · Jan 10, 2024

Steve_W said:
In a repeater, the advantage a 338 Norma Improved has over the .338 EDGE and .338 RUM is that one can easily run it in a 3.850" magazine with a 300 gr Berger and still use all of the available case capacity - with resulting velocities virtually equal to the longer cartridges. The EDGE and RUM require 4.0+" COAL when throated properly for the longer bullets.

For those interested, world-class 1K BR shooter Tom Mousel has started a discussion thread here on his current load development with the .338 Norma Mag Improved.

Hello SwampLord:
I just watched your vid of the 338 PRO. Highly impressive.
Would you mind sharing the stats of the reamer dimensions with me?
Looks like a 338 Norma with 40 deg shoulder?
Anyhow, I have been trying to decide on my next Long Range caliber in .338
I have decided on a .338 Norma or Norma A.I.
What I would like to know is your shoulder angle and freebore length & Case OAL
I plan on using 285 up to 325 gr projectiles.
Thanks a bunch!
John

LongJohn · Jan 10, 2024

Swamplord said:
the first animal back in Sept 2017 (one week before the bull moose) was this black bear, the 338 PRO with the 325 gr Chinchaga bullet whacked him good at 530 yardsView attachment 7255275 View attachment 7255276

Swamplord said:
View attachment 7255272 View attachment 7255273

Just in case my message was misquoted to the wrong person.
SwampLord...
would like your reamer dimensions.
Thank you for sharing what you have here Sir,
John

Swamplord · Jan 15, 2024

You can get the 338 PRO print and reamer from PT&G, I currently don't have any of my stuff uploaded to my new iphone

I've slightly modified that design with a few tweaks I felt were beneficial for the newer bullets and the availability of faster twist 338 cal barrels

LongJohn · Jan 17, 2024

Swamplord said:
You can get the 338 PRO print and reamer from PT&G, I currently don't have any of my stuff uploaded to my new iphone

I've slightly modified that design with a few tweaks I felt were beneficial for the newer bullets and the availability of faster twist 338 cal barrels

View attachment 8323531

For some reason I am not seeing an option to look up Reamer Blueprints on PT&G's website.?
So you had all this custom made but don't know your shoulder angle and freebore?
Every rifle I do and when I spec out my reamers made by Manson, I seem to remember the specs I called out.
And if I forget that info it is usually laser beamed right on the reamer itself.
Thanks for your help anyways

Swamplord · Jan 20, 2024

LongJohn said:
For some reason I am not seeing an option to look up Reamer Blueprints on PT&G's website.?
So you had all this custom made but don't know your shoulder angle and freebore?
Every rifle I do and when I spec out my reamers made by Manson, I seem to remember the specs I called out.
And if I forget that info it is usually laser beamed right on the reamer itself.
Thanks for your help anyways

you should have Manson do one up for you the way you want from your photographic memory

then you can GFY with it

LongJohn · Jan 23, 2024

Swamplord said:
you should have Manson do one up for you the way you want from your photographic memory

then you can GFY with it

Judging by your response I ascertain you weren't ever Military and didn't learn much about respect, or if you were the discipline never accomplished the desired goal of humility.
Given the situation I'm going over your head SIr...and am going to pray for you.

45-90 · Jan 23, 2024

No...not worth the extra effort...for me. 2 or 3 grains increase mentioned, means little velocity gain, especially with large heavy bullets. Cause when ya add more case volume, by improving, ya gotta add more powder to keep the pressure at the same level, as when the case was of smaller volume, to get the same velocity as before with the smaller volume case. Add another grain of powder to the improved case for the same velocity...at the same pressure.
Run the smaller case a bit over pressure will have the same performance.
Or change to a longer bullet seating depth, does the same thing without improving...or do both improve and long COAL for the best velocity outcome...but the extras space has to be filled with more powder to get the same velocity, at the same pressure, as the smaller volume case,
All for a small gain,..but it may look cool.

Taylorbok · Jan 23, 2024

LongJohn said:
For some reason I am not seeing an option to look up Reamer Blueprints on PT&G's website.?
So you had all this custom made but don't know your shoulder angle and freebore?
Every rifle I do and when I spec out my reamers made by Manson, I seem to remember the specs I called out.
And if I forget that info it is usually laser beamed right on the reamer itself.
Thanks for your help anyways

All that is on any of my reamers is what I named the cartridge. Doesn't specify any measurements on the reamer itself.

Contact PTG they will email you the print.

By the sounds of it he went through a few iterations and also clearly said he didn't have the print handy, not to mention the amount of cartridges he's done can't remember everything.

That being said I'd use Manson or JGS, I've tried PTG a few times and had bad luck. If you contact them they will have a Lap Imp reamer print. I'd spec it myself personally but to each their own.

Swamplord · Jan 25, 2024

LongJohn said:
Judging by your response I ascertain you weren't ever Military and didn't learn much about respect, or if you were the discipline never accomplished the desired goal of humility.
Given the situation I'm going over your head SIr...and am going to pray for you.

Judging from your Karenesque reaction when your demands weren't met STAT ...... I'm going to ascertain that you think you're something special and I'm supposed to divulge any and all information you demand- on the double .....

I'll be nicer this time ....
Go make Love to yourself

bbhank · Feb 5, 2024

I've got my .338 norma improved running 2907 fps with 300 bergers and 97.5 n570.

just know its a lot of work building a wildcat. I mean you have to get a reamer made then once you do that you need twice fired bras to have a sizing die made, you also need a seating die made, dies alone could take 2-3 months.

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