Reload: 410 gr woodleigh sp, 109.5 grain hogdon h1000. No h1000 in stock here in Norway. Trying to fond equivalent lodd using n570 which has a little slower brun rate. N570 is also a "progressive powder" perhaps leading to reduced peak pressure. Any thoughts? And should i expect regulation difficulties (Krieghoff regulated using h1000 109.5 gr)?

N570 is one of my favorite powders for big cases.

About 115grains of N570 will give you the same velocity as 109.5grains of H1000 but generate lower pressures.

My advice is to start at 112 grains of N570 and work up from there to 115-116.

Good luck and stay well

quote:

Hogdon h1000 to vithavuory n570

By the way; it´s VIHTAVUORI N570

Thanks for the heads up. Will start at around 112 grains and work up

Tried 113 grain loads, shot low and regulation is off by 6-7 inches at 100 meters. Went up to 115 grains and got the right height but regulation still off by 6-7 inches (left barrel shoots 7 inches to the left). Good groups of individual barrels <2 inches.

What could explain this difference? I have not chronographed yet but what would be the mechanism the difference?

Hogdon h1000 109.5 grains regulates perfectly...

If you have access to a chronograph, I think it will hold the answer. Chrono your H1,000 loads first for a baseline and then the N570 load. I would do both on the same day so as to limit variables related to weather and temperature.

I think the velocity was too high. Don't have a functional chronograph. But the barrels cross a lot earlier than with H1000 and this must be from higher velocity. Also recoil felt a bit firmer. No pressure signs tho. No sooting on the N570 loads as well (H1000 loads soot a bit), perhaps indicating higher pressure in the 570 loads. I'll stick with H1000 for 410 grain Woodleighs.

But I have some 570 powder left and I am thinking about testing the powder for 450 grain woodleigh softpoints I have lying around. I was thinking if increased velocity from changing powder was the reason for the horisontal spread and that loading heavier (+40 grain bullets), maybe starting at 110 grain N570 and working from there may regulate (lower velocity)? There is no available data for this.

I was firing 410 grain bullets with 116 grains 570, would it be safe to assume that 110 grains is a good starting point for 450 grain bullets? I do of course take full responsibility for my experimentation

Borrowed a chronograph and it did tell a different story than my speculations...

115.5 grains N570, 410 gr Woodleigh = 2290fps, around 100 fps less than expected.

So the reason for horisontal spread was not high velocity but probably low.

I then tested out loads with 450 gr Woodleigh.
109.5 grains N570 450 gr woodleigh sp = 2240fps

Just shot thorugh the chrono and have no idea about how the load regulates but it is interesting that i get almost the same velocity with less powder behind a heavier (+40gr) bullet.

Does this indicate too low pressure for the light bullet? I saw no pressure signs on the cases (no flat primers etc) on any of the loads. Started at 106 grains and built up to 109.5 for the 450 grain bullet.

Also the velocity of the 450 grain bullets equal that advertised by norma on their factory loads using the same bullet. Should I expect that their factory load with the 450 grain bullet regulates similarly to the one with 410 grain bullets in most modern doubles?

With a SD of .371 and at 2300 fps (i expect to safely get this with 110.5 grain N570) I would think this 450 grain 416 round would be a pretty good for cape buffalo! Good expansion and penetration as well as decent trajectory.

Has anyone tried RL22 or RL25 or maybe even Retumbo or H4831sc? Or anything else?