338 Norma or 338 Norma Ackley?

[Ledd Slinger]

On an interesting side note, figuring out how to seat a bullet in the 338 Norma brass without a 338 Norma seating die was a fun exercise. First thought was to just run it through my 338 Lapua seating die (Redding Competition Seater). That was a 'no-go'... Not enough taper in the 338 Norma case for it go very far into the sliding sleeve of the 338 Lapua die before binding up. Hmmmm, time to disassemble...

I just set the sliding sleeve aside and reassembled the seating die, minus the seating stem which is held in place by the sliding sleeve. Slid the seating stem onto the top of the bullet that I wanted to seat, set the bullet with seating stem atop it into a piece of brass, aligning the best I could, put it all in the shell holder, raised the ram, and adjusted the micrometer as needed. It worked great. For kicks, I measured concentricity on the two dummy rounds seated this way. Runout on the 285 gr ELD-M was 0.002" and 0.001" on the 300 gr Hybrid.

View attachment 1039511

View attachment 1039512

Can just take a seater stem and tap the bullet into the case with a rawhide mallet too. Pretty simple.

 

[TikkaSporter]

Heard word from a Lapua rep that the intital test cases have neck walls that are right around .0145" to .015". That would give you roughly a .368 loaded round.

Yes, that is my concern. I measured 0.001" - 0.0015" less on the neck walls of Norma brass and am getting just under 0.365" on my dummy rounds. The 338 Norma 40 reamer print I'm looking at shows a 0.37122" - 0.3705" neck diameter (tapered neck). So if I understand correctly, if the Lapua brass ends up at 0.368, that's only 0.002" - 0.003" of neck clearance with the reamer in the print. Prefer at least .004".

Also, what's the benefit of a tapered neck?

 

[Ledd Slinger]

Yes, that is my concern. I measured 0.001" - 0.0015" less on the neck walls of Norma brass and am getting just under 0.365" on my dummy rounds. The 338 Norma 40 reamer print I'm looking at shows a 0.37122" - 0.3705" neck diameter (tapered neck). So if I understand correctly, if the Lapua brass ends up at 0.368, that's only 0.002" - 0.003" of neck clearance with the reamer in the print. Prefer at least .004".

Also, what's the benefit of a tapered neck?

I know it's less work to fire cases with unturned necks, but cases perform so much better with the necks at least cleaned up with turning. Better tension, better runout, etc.

Not sure on the tapered neck. I never design my reamers that way. Maybe it has something to do with expanding the base of the neck when fired so a formed donut doesnt drag on the bullet bearing surface when bullets are seated deep in the case.

 

[RustyPin]

Have you priced a difference between the two? I'm not an expert but I saw David Tubb announced at the Shot Show he's coming out with a New Cartridge to compete with these.

 

[TikkaSporter]

Have you priced a difference between the two? I'm not an expert but I saw David Tubb announced at the Shot Show he's coming out with a New Cartridge to compete with these.

Between which two? 338 Norma and 338 Norma Ackley Improved? Sort of. A lot more expensive to go with the Ackley version unless I can find a gunsmith that already has a 338 Norma Ackley reamer with the correct neck clearance for no-turn with the lapua brand brass. Looks like a custom reamer and Go Gauge from JGS will be ~ $320 and 8 weeks wait. This isn't all about cost, or I'd just stay with the 338 Lapua and deal with donuts.

As far as Tubbs new cartridge, it's intended for ELR competition shooting. My intentions are magazine fed, long range, elk hunting. Probably two different sets of design parameters, especially the magazine fed part, but I could be wrong.

 

[RustyPin]

Does the THOR compare to the Norma AI?

 

[Drop Port]

27" Bartlein barrel. 1:10 twist. 5R rifling.
- 300gr Berger Hybrid, Lapua brand brass, 91.5gr H1000, 2860 fps, 3.715" OAL
- 285gr Hornady ELD-M, RWS brand brass, 91.0gr H1000? (need to verify), 2875 fps, 3.636" OAL

My standard 338 Norma runs 60 FPS slower with H-1000 out of a 26" barrel, an improved will outrun your numbers with R-33. I'm hopeful that Lapua brass will do the same for this cartridge as its done for others and give it even more.

 

[pawater]

Peterson Brass is coming out with, 300 and 338 Norma brass very soon. It is on par with Lapua for Quality. I have been waiting to do the improved version as well. RBros rifles has a reamer on order for the improved and Lapua brass. (No turn).

 

[TikkaSporter]

Peterson Brass is coming out with, 300 and 338 Norma brass very soon. It is on par with Lapua for Quality. I have been waiting to do the improved version as well. RBros rifles has a reamer on order for the improved and Lapua brass. (No turn).

Good to know, if the Graffs website is correct, they will be selling the 300 Norma Lapua brand brass for $207/100 and the 338 Norma Mag Lapua brand brass for $306/100 ... Wonder what the Peterson brass will be priced at?

I've ordered my custom 338 Norma mag Ackley reamer from JGS after having no luck finding a gunsmith that carried this reamer in a no-turn neck. I had them take the taper out of the neck and open up the neck diameter 0.001" from the print they had on-hand, to better accommodate a presumably thicker neck with the 338 brand brass.

 

[TikkaSporter]

OK, the reamer arrived and the rifle/reamer/barrel are at the smith being chambered now. Need to make a few fire-form loads for the smith to function test with. Any suggestions on where to start?

I've got H1000, RL-22, RL-25, & H4831 powder on hand and 300 Berger, 300 SMK, 285 ELDM, old 275 Speer bullets on hand.

 

[Drop Port]

PM sent H-1000 will form them up and is often very accurate. I would get some R-33 and look for 2920 ish fps

 

[jb1023]

PM sent H-1000 will form them up and is often very accurate. I would get some R-33 and look for 2920 ish fps

Just wanted to see if you had any updates on this build?

 

[TikkaSporter]

Just wanted to see if you had any updates on this build?

Got the rifle back from the 'smith a week ago. Haven't had time to play with it yet, and STILL no Lapua brass available! I have 20 rounds of Norma brass for now.

 

[Tommie]

Ackley versions of cartridges usually get up to 25% less barrel life.

Can you expand upon this theory?

 

[Bart B.]

Can you expand upon this theory?

Ackley versions of cartridges usually get up to about 20% less barrel life because they burn more powder.

Years ago, a study was done with accurate barrel lives for different cartridges used in competition, hunting and service rifles. The standard used was average extreme spread accuracy with 10 shot groups when barrels were new then round count when it increased 50 percent.

Data revealed that when powder charge weights in grains number was the same as the bore cross section area in square millimeters, match grade rifle barrels shooting match bullets got about 3000 rounds of barrel life before groups average ES increased 50% from 1/4 MOA to 3/8 MOA.

Hunting rifle barrels starting out with 1/2 to one MOA average go about 6000 rounds until groups averaged 50% bigger groups. USA 30 caliber service rifle barrels were considered worn out around 10,000 rounds starting about 2 to 3 MOA.

Sierra Bullets got about 3,000 rounds of test barrel life in 308 Win test barrels burning 43 to 46 grains of powder. So did match winning and record setting 308 Win competition rifles. 30-06 such rifles got about 2300 rounds.

For match grade bullets and barrels:



Forum member mikecr made an Excel program that adds powder heat indices because hotter powders wear out barrels faster for given charge weights

http://www.accurateshooter.com/technical-articles/excel-formula-predicts-useful-barrel-life/

 

[jb1023]

Got the rifle back from the 'smith a week ago. Haven't had time to play with it yet, and STILL no Lapua brass available! I have 20 rounds of Norma brass for now.

So your reamer is a 338 Norma Mag Imp that has 40* shoulder, no neck taper, a no turn neck based on Lapua's case dimensions? Can you fireform standard 338 Norma brass without prior modification?

Based on my emails to the various brass mfg's:
Lapua won't be available till around April '19.
Peterson version 2.0 will be available 1st qtr '19.
ADG will be available hopefully sometime in '19 (would not be more specific).

 

[TikkaSporter]

So your reamer is a 338 Norma Mag Imp that has 40* shoulder, no neck taper, a no turn neck based on Lapua's case dimensions? Can you fireform standard 338 Norma brass without prior modification?

Based on my emails to the various brass mfg's:
Lapua won't be available till around April '19.
Peterson version 2.0 will be available 1st qtr '19.
ADG will be available hopefully sometime in '19 (would not be more specific).

Yup, in theory the only difference would be a bit more neck clearance with the 338 Norma brass verses the 338 Lapua brass. In reality, having just fireformed a couple pieces of Norma Brass, the neck is still pretty tight. A bullet doesn't drop into the case mouth, it slides in and not exactly easily. If the neck on the Lapua brand brass is much thicker, I may end needing to skim-turn the necks.

Now the real question. Do I need to wait for the Lapua Brass to fireform 3x and send in for custom dies? Or am I fine sending in fireformed Norma Brass for the dies?

In my mind it shouldn't matter because the outside dimensions should be the same with either brand of brass after firing 3x, neck-sized only, as it should match the chamber. Neck thickness shouldn't come into play with a bushing sizer die. Am I missing something?

 

[boltfluter]

Sounds like a plan to me. Who actually knows when the Lapua brass will be available. A light skim cut on necks is never a bad idea! Good luck and have fun.

Paul

 

[rpierce]

The lapua brass in 300 norma I have is some of the most consistent stuff Ive seen. Loaded neck diameter was dead nuts, .338. Roughly .00075 or 3/4 of a thou variance. And that was the extreme end on the 20 or so I measured before I realized I was wasting my time and had no reason to neck turn it. Most were half thou or less. Im glad I snagged 4,000 pieces of it a few months ago seeing as the new projected date is April 19. I bought it so guys Im building rifles for would have some Lapua brass for their new 300 norma improved hunting rifles. I had honestly thought about doing the 338 route but in a light weight setup the added recoil isn't worth it due to the 215 berger at 3300 fps being an absolute laser beam. Actually beats the 338's except in energy. But a 215 still has 1540 ft lbs of energy at 1400 yds in average elk hunting altitudes, 5000 ft elevation. More than enough to harvest a big game animal. Not discussing ethics on it so don't mention it.

 

[jb1023]

The lapua brass in 300 norma I have is some of the most consistent stuff Ive seen. Loaded neck diameter was dead nuts, .338. Roughly .00075 or 3/4 of a thou variance. And that was the extreme end on the 20 or so I measured before I realized I was wasting my time and had no reason to neck turn it. Most were half thou or less. Im glad I snagged 4,000 pieces of it a few months ago seeing as the new projected date is April 19. I bought it so guys Im building rifles for would have some Lapua brass for their new 300 norma improved hunting rifles. I had honestly thought about doing the 338 route but in a light weight setup the added recoil isn't worth it due to the 215 berger at 3300 fps being an absolute laser beam. Actually beats the 338's except in energy. But a 215 still has 1540 ft lbs of energy at 1400 yds in average elk hunting altitudes, 5000 ft elevation. More than enough to harvest a big game animal. Not discussing ethics on it so don't mention it.

What is your load that you are able to achieve those kinds of speeds? That has to be a hot load based on what I'm seeing in QL. That exceeds my expectations for sure in this cartridge.