Optimum .338 Norma Magnum barrel length?

[lv2hunt]

Hello,

3-months ago I ordered a stainless 30" Hart, heavy custom contour, fluted, 1:10 twist rate barrel for my next long range rig chambered in what I thought would be .338 Lapua Magnum. I was planning on using primarily the 300-grain Berger bullet or possibly the SMK or Accubond. Fast forward to now, I have received the new barrel and after a TON of research have decided to build a .338 Norma Magnum in lieu of the Lapua. Many factors played into this decision, the main reason being that this is a magazine fed weapon and I could utilize the shorter case to my advantage for feeding and bullet seating.

My question after reading probably every thread out there online on the subject is what is the optimum barrel length for a .338 Norma Magnum? From what I have gathered the cartridge was built and tested around a 26" barrel, some say 28" is better, and mine is a 30". I am inclined to stick with the 30" because I could always go to 28" at a later date if needed, expecting to get around 2,750 fps. What are your thoughts?

Thanks,
lv2hunt

 

[Mike 338]

Hello,

3-months ago I ordered a stainless 30" Hart, heavy custom contour, fluted, 1:10 twist rate barrel for my next long range rig chambered in what I thought would be .338 Lapua Magnum. I was planning on using primarily the 300-grain Berger bullet or possibly the SMK or Accubond. Fast forward to now, I have received the new barrel and after a TON of research have decided to build a .338 Norma Magnum in lieu of the Lapua. Many factors played into this decision, the main reason being that this is a magazine fed weapon and I could utilize the shorter case to my advantage for feeding and bullet seating.

My question after reading probably every thread out there online on the subject is what is the optimum barrel length for a .338 Norma Magnum? From what I have gathered the cartridge was built and tested around a 26" barrel, some say 28" is better, and mine is a 30". I am inclined to stick with the 30" because I could always go to 28" at a later date if needed, expecting to get around 2,750 fps. What are your thoughts?

Thanks,
lv2hunt

According to Ward Brien, 24.125" with a 9.3 twist is the magic formula. He did some testing with a longer barrel and cut it back a little at a time, all the way to 22". He thinks that after 26", the increase in barrel length is not worth it.

 

[lv2hunt]

Thanks for the reply, I read that article. Anyone have any real world load data
or results from their own rifles?

Lv2hunt

 

[sydleier]

I recently built one with a 28" barrel and am just working up a load. Where in SoCal are you? I'm in LA

 

[lv2hunt]

Just north of San Diego. Congrats on the new rifle, please share your load data when you get it figured out.

Thanks,
lv2hunt

 

[sydleier]

Will do - my cousin has the exact same rifle that's shooting well with

Norma Brass
CCI 250's
92 grains of Retumbo
300 grain Bergers 0.005 off the lands

He's right @ 2775 fps

I just loaded up a string with the same components from 88 grains up to 92 I'll let you know where I land.

-syd

 

[sp6x6]

If you read all those posts, you will see that many are shooting your target velocity in 26".I get 2725-50 in 26'',87.5 retumbo.Many pushing it harder.If I had that long stick I would want a 338 LAI,and not worry about mag.But I already have a AI fed Norma

 

[lv2hunt]

Thanks for the replies please keep them coming! So general consensus seems to be that a 26" to 28" length on the barrel would be optimum all things considered. From what I have gathered it looks like at 26" one can expect around 2,750 fps with a 300-grain pill, and about another 30 to 50 fps gain for every inch up to the 30" mark. Overall weight aside, I believe my 30" barrel will be suitable for my needs, I can always cut it down if needed. I am a little concerned as well about the twist rate that I have, mine is a 1 / 10 is this workable?

Thanks,
lv2hunt

 

[lv2hunt]

Finally settled on cutting it down to a 28" barrel. Will post results when I get the rifle finished.

Thanks,
lv2hunt

 

[sp6x6]

I run a brake and for feel of the rifle, swing it in timber I would be happy w/26'' the brake adds length. You dont gain that much in fps. If you want more speed go for a improved version or short life on brass.

 

[Sully2]

From the bench you can use what you want to....but in the field Id never go over a 26" barrel. Too much hassle in many ways

 

[lv2hunt]

True about longer barrels, but this isn't exactly a pack rifle. 28" will suit my needs fine, to be honest with the brake the total length will be 30 1/2". 26" for this caliber would of been more than adequate, but I had a 30" .338 barrel from Hart already so I decided to cut it right down the middle at 28" length. Going to suit my needs just fine.

Thanks,
lv2hunt

 

[Bear Camp]

I have a 338 RUM with a 26" Heart barrel and a 338 EDGE with a 30" Heart barrel both with a 1-10 twist that shoot lights out. You will be just fine with that twist rate. Oh, I'm shooting 300gr SMKs and the 300gr Bergers.