338 Norma Reloading Data

highdrum

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Nov 30, 2008
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Ok, so my magneto speed went on the fritz, was a frustrating day, didn't accomplish much ha ha. I ended up ditching N570 as I only have about 1.5 lbs left, and I'm not having any luck getting more, though 91 grains did shoot pretty well, at around 2860 I believe. I bought a labradar, just got out today, and did a max pressure work up with Retumbo and IMR7828ssc, ended up with this -

250 SBDII
Peterson brass
GM215M
.025 off
24" Lilja 4 groove barrel

RETUMBO -
91 - 2862
92 - 2903
93 - 2924
94 - 2963 - discontinued, entire group right at 1 MOA ctc, with 91-93 being sub .75" @100

IMR7828ssc -
86 - 2922
87 - 2962 - discontinued, the two were 2" apart

If I was going to continue IMR7828ssc, I would start around 83 grains and work up from there, probably around 2820-2830 to start. I'm going to continue my work up with retumbo, likely doing a ladder from 91 to 93.
This is standard 338nm? I'm kinda wondering where my 338 rum w/ 28" barrel would run. I have accuracy with N570 and 300s @ 2850fps.
 

codyadams

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Jan 7, 2015
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3,491
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Southwest Wyoming
This is standard 338nm? I'm kinda wondering where my 338 rum w/ 28" barrel would run. I have accuracy with N570 and 300s @ 2850fps.
Ya, standard Norma, 24" Lilja barrel. I tend to run my loads pretty conservative as this is built on a Remington action, I have never once seen ejector marks or heavy bolt lift, only light primer cratering on a couple loads, and I mean light. With a 28" standard .338 NM built on a stiller TAC .338 action, I ran the 300 Bergers up to 2925+ fps with Retumbo, and still didn't see ejector marks, increased bolt lift, clickers or anything, I stopped because I knew the extreme velocity could only be due to high pressures. The ADG brass is, I would nearly say, dangerously tough stuff. You can run stupidly high pressure, and other than the velocity and possibly primer catering, have no signs. I am starting my 8th firing of this 50 pieces of Peterson brass in my .338 NM, and have no signs of wear, primer pockets feel new, no separations, no cracked necks, nothing, and I have not annealed brass as I do not have an annealer yet. When funds allow it, I will....

I run that same 28" .338 NM at 2850 with 300 Bergers, using Retumbo. It is a very accurate load in that gun. From what I have seen, a .338 rum and .338 Norma are pretty similar. When it is time for another barrel, I am going to go .338 NM improved, I think that would boost performance a bit, and be an overall sexy looking cartridge ha ha
 

Lonewolf74

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May 12, 2016
Messages
533
Hey Cody, I seen a few post back that you had some loads done up in N570 and N565. I know you also said you discontinued development with the 570 cus of getting low but I was wondering how the load was panning out velocity wise? Also how was the 565 stacking up? I got a few lbs of 565 but I haven’t played with it in anything yet.

I have several lbs of 570 stashed but I’m actually hoping to find some imr 7977 and 8133 to test and really hoping it runs great cus I’m sort of tired of always trying to find 570 and 565. Before the current market situation I could find the imr powders everywhere.
 

codyadams

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Jan 7, 2015
Messages
3,491
Location
Southwest Wyoming
Hey Cody, I seen a few post back that you had some loads done up in N570 and N565. I know you also said you discontinued development with the 570 cus of getting low but I was wondering how the load was panning out velocity wise? Also how was the 565 stacking up? I got a few lbs of 565 but I haven’t played with it in anything yet.

I have several lbs of 570 stashed but I’m actually hoping to find some imr 7977 and 8133 to test and really hoping it runs great cus I’m sort of tired of always trying to find 570 and 565. Before the current market situation I could find the imr powders everywhere.
I got through most of the N570, not all, and started N565 but that is where my magnetospeed bit the dust. Velocities were as follows -

250 SBDII
Peterson brass
GM215M
.025" off

N570
91 - 2832
92 - 2824
93 - 2849
94 - 2886
95 - 2890

N565
86 - 2719
Then my magnetospeed died. Lol
 

codyadams

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Jan 7, 2015
Messages
3,491
Location
Southwest Wyoming
Ok, so I was getting ahead of myself, and forgot to do a seating depth test, so instead of a ladder I checked seating depth, and found out that in my gun, this 250 SDBII HATES being close to the lands ha ha. Instead of writing it all out, I'll just post photos to see. Groups were shot at 250 yards.

20210519_141245.jpg
20210519_141328.jpg


On the target, I listed that I started at .015" off, but I really started at .010" off. Anyway, as you can see, .010" off was terrible, and .030 wasn't great either. After that, they all went down to sub MOA, with .050 being right at or just over half MOA, and .110" not far behind it. You can see velocities drop as well from the bullet having farther to move so as to drop pressure before hitting the lands.

Now - next thing is a 600+ yard ladder. Already have them loaded up.
 
Last edited:

codyadams

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Joined
Jan 7, 2015
Messages
3,491
Location
Southwest Wyoming
Had pretty good results with my 600 yard ladder test, from the pics below you can see that there seems to be a pretty good node around 91.2 through 92.4 before it jumps significantly. The wind was pretty shifty, going anywhere from almost non existent up to 6 or 7 at times, I held off for three rounds but decided to just have the same windage hold and see how much it affected it, so I don't put too much weight in the lateral movement. But 91.5-92.4 had less than 1 inch of vertical, even with 43 fps velocity variance over almost a full grain of powder.

It seems like it may have been starting to settle down about at 93.2 and 93.5 in the low 2900 fps range, I may play with that a little bit, as the velocity there seems pretty stable too, but if not, 92 grains around 2875 would probably be sufficient.

20210522_082125.jpg
20210522_170114.jpg
 

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