300 Win Mag and N570 new Norma brass

[Ironworker]

I was shooting 208 ELDms from my new 300 Mag. C.O A.L 3.500. 79.5 grs N570 Fed 215 primers. I was getting over MOA at 100yds, and the EXT spread was 100FPS(2,839-2,942) and SD about 60. That isn't very good. Even so, I could hit the gongs at 300-400 yds. 10" rifling twist Bergara B-14 HMR. What could be the cause?

 

[cuznguido]

You might want to try a faster powder and compare results, then proceed from there. My two cents says that 570 is a bit slow for that setup, but JMO. Like the 570 just fine though, to be clear.

 

[FeMan]

N570 is too slow for that case to hold enough powder to get the pressure up for a good burn. Sounds like a perfect combination for H1000.

 

[DocBII]

Ironworker,

Try heavier bullets, 225 class or heavier if the twist will support them.

HTH,
DocBII

 

[Ironworker]

Ironworker,

Try heavier bullets, 225 class or heavier if the twist will support them.

HTH,
DocBII

Interesting, my rifle has a 10"twist 26" bbl

 

[46and2]

I was shooting 208 ELDms from my new 300 Mag. C.O A.L 3.500. 79.5 grs N570 Fed 215 primers. I was getting over MOA at 100yds, and the EXT spread was 100FPS(2,839-2,942) and SD about 60. That isn't very good. Even so, I could hit the gongs at 300-400 yds. 10" rifling twist Bergara B-14 HMR. What could be the cause?

I responded to your LRO post.
My load for my one 24" factory Savage 300wm and 208eld is 7828ssc lit with 210 standard primers 5 shots under .5moa at 200 yards.
2950 fps no pressure, my brass will last a while, es is less than 20.
Unfortunately 7828 is the only powder the I have not found since the plandemic. I'll have to try H1000 or n565 when my stash runs out.

 

[Mike TackleBerry]

I was shooting 208 ELDms from my new 300 Mag. C.O A.L 3.500. 79.5 grs N570 Fed 215 primers. I was getting over MOA at 100yds, and the EXT spread was 100FPS(2,839-2,942) and SD about 60. That isn't very good. Even so, I could hit the gongs at 300-400 yds. 10" rifling twist Bergara B-14 HMR. What could be the cause?

79.5 grains of N570 with 3.500 COAL gives you 100% case fill capacity with a Pmax pressure of around 48,471 PSI. Quickloads show a velocity of 2830 fps. N565 would be a better fit with the 208s, Even N568 would work well.
79.5 of N565 with a COAL of 3.500 shows a velocity of 2961 fps with a Pmax pressure of 63K psi. It might be a tad hot though.

 

[Walt Krafft]

Two proven accurate loads are Re22 73.0 190 SMK and H1000 73.0 220 SMK. Work up with these powders and you should be happy.

 

[46and2]

I was shooting 208 ELDms from my new 300 Mag. C.O A.L 3.500. 79.5 grs N570 Fed 215 primers. I was getting over MOA at 100yds, and the EXT spread was 100FPS(2,839-2,942) and SD about 60. That isn't very good. Even so, I could hit the gongs at 300-400 yds. 10" rifling twist Bergara B-14 HMR. What could be the cause?

N570 is a very useful powder to me. I use it in overbore cartridges. 300rum with 230gr otm, 27 Nosler with 170gr Elite Hunters. I've tried it in 300wm with 215gr Hybrids. I didn't get any velocity advantage but major compression.
My conclusion is n570 belongs in my 300rum.

 

[L.Sherm]

I loaded for a friend's 300WM with the 185 Berger tried H1000 and 565 couldn't get enough in the case, when it got upto 3100 and started to act like it wanted to shoot it was crunching powder and got real inconsistent and I switched to RL23 and I tested it at 325 and it shot 1" at 3125fps

 

[Mike TackleBerry]

I loaded for a friend's 300WM with the 185 Berger tried H1000 and 565 couldn't get enough in the case, when it got upto 3100 and started to act like it wanted to shoot it was crunching powder and got real inconsistent and I switched to RL23 and I tested it at 325 and it shot 1" at 3125fps

H4831SC would work good for the 185s.

 

[SKWERLZ]

N570 is a very useful powder to me. I use it in overbore cartridges. 300rum with 230gr otm, 27 Nosler with 170gr Elite Hunters. I've tried it in 300wm with 215gr Hybrids. I didn't get any velocity advantage but major compression.
My conclusion is n570 belongs in my 300rum.

Yep
It’s wonderful in my 338 edge.
Really good case fill.

 

[L.Sherm]

I cant complain about this