338 Norma Mag barrel length?

[bigngreen]

I'm getting started on a 338 Norma Mag build and was wondering if there is much to gain from a 30+in barrel. Most of the info I can find has been on rifles with shorter barrels. I'm interested in shooting the 300gr Berger or SMK's only and the length does not matter I just want to get the most out of it.

 

[AK10mm]

Re: 338 Norma Mag barrel length?

What made you decide on a 338 Norma Mag ? Just curious is all.Don't really know anything about that cartridge.

 

[bigngreen]

Re: 338 Norma Mag barrel length?

My decision to go with the 338 Norma Mag is mainly based on that it is designed for a standard long action with good bullet placement with a 300gr projectile. I'm wanting to run it in the 2750-2800fps range and this seems to be an excellent way to do that. Also looked at the 338 Edge and 338 RUM but I really like the bullet placement in the case of the 338 Norma.

 

[pc3]

Re: 338 Norma Mag barrel length?

I opted for a 28" barrel...........but general felling is that it was designed around a 26" tube.

In hind site Id have gone 26" I still love it though 90gr of Retumbo gives me 2738 behind 300 gr SMK with Pills in the right spot.

 

[ganyana]

Re: 338 Norma Mag barrel length?

All our development was done here in Sweden with 26" barrels. I suspect Jimmy Sloan used 28" in original design. The bulk orders have specified either 26" or 27" barrels....

 

[RWSGunsmithing]

Re: 338 Norma Mag barrel length?

You'll gain a little with a 30" barrel but is it worth the extra length and weight to you? If it's going to be a bench gun only go for it but if your going to use it in the field I would go with a 26-27" max length.

Most builds here are 26"

 

[bigngreen]

Re: 338 Norma Mag barrel length?

What kinda of gains are we talking? I have no problem with a long barrel if I can see some gain. Primary concerns in order are; accuracy and consistency then FPS and weight, I want to shoot this rifle a lot, it will be my first rifle that is capable of accuracy beyond 1000yrds so I want to spend some significant shooting time learning what it takes to reach out to the mile mark.

 

[Raggs]

Re: 338 Norma Mag barrel length?

No Sir,
From day 1 before this cartritge was a Norma it was always written in the respect of 26.0 barrel length,i dont believe that i ever responded to anyone asking for any information was ever suggested in 27, 28 or 30 i only tried to discourage the lengths rather than encourage them

 

[bigngreen]

Re: 338 Norma Mag barrel length?

So is there a performance reason for staying with the 26in barrel or is it from the aspect of keeping the length in a manageable package that performed in a certain window?

 

[Raggs]

Re: 338 Norma Mag barrel length?

Over 26.0 to 27 i think there is a beginnig of a negative return for velocity vs barrel length, in the cartridge efficiency.

 

[ganyana]

Re: 338 Norma Mag barrel length?

Big green...If you are going to run an extra large action (Bigger than the AI) so you can use the .338 Lap with 300grn bullets seated right out...then you will need a longer barrel to make best use of the extra case capacity.

The .338 Norma was designed to be as accurate as possible out to 1 mile. I regularly get 1/3 MOA in testing - and that is with a veriety of barrels. If you want 2000 yards, If you don't mind the extra muzzel blast or greater weight..then get a .338 Lapua - it is a good cartridge - but many are asking things of it that it was not designed for and one of them is asking for 300grn bullets seated deep to fit into Rem 700 or AI rifles.

 

[pc3]

Re: 338 Norma Mag barrel length?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bigngreen</div><div class="ubbcode-body">So is there a performance reason for staying with the 26in barrel or is it from the aspect of keeping the length in a manageable package that performed in a certain window?</div></div>

So potentially my 28" tubed rifle with 90 gr of Retumbo behind the 300 gr SMK would give faster velocity's if I lopped to 26" ?

 

[C.K]

Re: 338 Norma Mag barrel length?

No, you get full burn with that load in a 26" barrel so why go longer? That is what Have none is getting at.

 

[bigngreen]

Re: 338 Norma Mag barrel length?

What's the average velocity that guys are seeing with the 26-28in barrels with a 300gr bullet?

I have talked with the guys at Brux and they recommended a 1-9.3 twist med palma, any opinions on this?

Thanks for the info!

 

[V-Ref]

Re: 338 Norma Mag barrel length?

27" 10 twist Lilja

91 gr H1000 (light compression) 2750-2775 fps....but pressure. Too quick a powder IMO.

92 gr Retumbo 25 fps quicker, but more compression. Too slow a powder...can't fill case with enough to achieve velocity potential IMO.

Which led me in a big circle back too.....RSM. 90-92.5 RSM 2800-2820 fps....

Do a search for Have None posts on this thread....you'll see the recommended load data. It's spot on in my book.

Looking forward to trying V570.

BTW-At equal powder charge levels, WLRM primers have been about 15-20 fps slower than the F215GMs for me in this chambering.....WLRMs are good match for RSM and this case IMO, as I needed to back the charge down some when using F215GMs vs. WLRMs to achieve the same velocity/pressures.

 

[ganyana]

Re: 338 Norma Mag barrel length?

RUAG Amotech factory ammo gives 2650fps with a 300grn bullet (of their own not a Sierra MK) from a 27" AI rifle.

My own top accuracy loads Using MRP powder does 2640fps from a 26" barrel. This is well below maximum load though (400mPa)but the Bullets carry to 1600m and gives the best accuracy. I can get a little more velocity with some of the other slow burning double based powders but really need to use some of the 'boosted' powders if you want more speed from the .338 Norma sized case.

I have been able to add 100fps to this speed well within Pressure limits (max pressure is 440 mPa) with St Marks powders, but haven't been able to hold 1/3 MOA. A change of primers, a bit more experimenting....who knows...that's why I follow the forum. it gives me ideas.

 

[Møønlight]

Re: 338 Norma Mag barrel length?

26" is what's recommended.

MS

 

[gyr]

Re: 338 Norma Mag barrel length?

Going to a 24 or 25 " barrel would reduce velocity in some 30 fps/ inch???

I wonder if it would make sense to launch the 300smk under 2650 ft/s with mild loads.

 

[pc3]

Re: 338 Norma Mag barrel length?

My 28" Lilja 1-10" tube with 90gr of Retumbo behind the 300gr SMK averages 2738 fps...............I dont feel the need to drive it any harder.

 

[PEACEMAKER]

Re: 338 Norma Mag barrel length?

So no one recommends a 1in 9 twist, 20inch barrel for the NM then? That's what I was the combo i was toying with using to build mine. I already have a .338lap in a HS HTR2000 but were having issues her in OZ with " sniper super magnums" and the powers to be.

 

[DAVETOOLEY]

Re: 338 Norma Mag barrel length?

Unless you're going to shoot subsonic ammo there is no reason to go faster than a 1-10. Actually a 1-12 will stabalize a 300 just fine. Consider the extra torque you're adding to the system during the launch. Barrel length 20-27" depending on intended use.

 

[Insite Arms]

Re: 338 Norma Mag barrel length?

Im getting 2800fps with a 300gr Berger and 93gr of Retumbo out of a 25" barrel. My ES is very low so I would guess the burn is consistently close to complete.

I would only be tempted to go a bit shorter if I were to do it again.

 

[Christopher Rance]

Re: 338 Norma Mag barrel length?

What would be the shortest barrel recommendation for field application? I was hoping something in the 20"-24".

 

[DAVETOOLEY]

Re: 338 Norma Mag barrel length?

20" works fine but I would recommend using a can. It's a lot more friendly that way.

 

[Christopher Rance]

Re: 338 Norma Mag barrel length?

Thank you.