Loose Magnetospeed Data Advice

[eod.tek]

Ill start by saying that I am very new to reloading and this is my first load development. I used the search function but still have a question.
I loaded up a test at 20 thousandths off the lands, using data/help I received from the forum and started at 80.6 grains, and loaded in .2 increments up to 83.2 (14 rounds). I was very diligent about checking my magnetospeed between the first 8-10 rounds, but it never shifted and I got complacent. on shot 12, 82.8 grains, I saw a drop in velocity I wasn't exactly expecting, and checked the magnetospeed and it had shifted forward about 1/2-1 inch. I fixed it and shot rounds 13 and 14. Of course, upon reviewing the data, the graph between 82.6 and 83.2 was almost dead flat, except for that 82.8 grain shot where the chrono was loose.
Am I best to load up those last 4 rounds again and reshoot it, is having the data I have and knowing it was loose on that shot enough to invalidate it and peruse that as a node? Any advice would be greatly appreciated!
Data from the days shooting:

Velocity	CW
2857	80.6
2894	80.8
2902	81
2896	81.2
2908	81.4
2905	81.6
2918	81.8
2920	82
2936	82.2
2922	82.4
2949	82.6
2934	82.8
2950	83
2950	83.2

My setup:
300 Norma Magnum
26" 1:9 Proof Carbon Fiber
230 rounds on the barrel
H1000
Lapua Brass
225 ELD Match
FED215M
Magnetospeed v3

 

[eod.tek]

 

[Rick Richard]

For that big of a caliber, I would go in .5 grain increments. And when in doubt as you are approach conservatively meaning do over. Just my opinion.

 

[eod.tek]

For that big of a caliber, I would go in .5 grain increments. And when in doubt as you are approach conservatively meaning do over. Just my opinion.

I had considered doing half grain increments, but I really was searching for a conservative and consistent load between 2850-2950 to spare some barrel life. When looking at all the load data I could find, both published and anecdotal, it seemed like a lot of people started hitting pressure signs around 83.5-84 grains and I just wasn't looking to push it up to max charge weight.

 

[Rick Richard]

I had considered doing half grain increments, but I really was searching for a conservative and consistent load between 2850-2950 to spare some barrel life. When looking at all the load data I could find, both published and anecdotal, it seemed like a lot of people started hitting pressure signs around 83.5-84 grains and I just wasn't looking to push it up to max charge weight.

Understand, but that may be where it wants to be shot to achieve desired accuracy. My NMI would only shoot what I considered to my expectations on the high end. Just my experience…and your not going to save that much on barrel life.

 

[Hugnot]

The velocities vs. powder charges are sort of linear - more powder more velocity.

For 14 rounds fired with incremental powder charge increases:

For the last 7:

My suggestion would be to load 5 each, 82.0, 82.5, 83.0 grains.

Look for accuracy, velocity uniformity & signs for excess pressure. Velocities tend to look good after 81.6. Components are pricy - be systematic.

 

[eod.tek]

The velocities vs. powder charges are sort of linear - more powder more velocity.

For 14 rounds fired with incremental powder charge increases:

View attachment 425534


For the last 7:
View attachment 425529

My suggestion would be to load 5 each, 82.0, 82.5, 83.0 grains.

Look for accuracy, velocity uniformity & signs for excess pressure. Velocities tend to look good after 81.6. Components are pricy - be systematic.

Is there any reason not to load 5 right in the middle of that bottom node as well? Around 81 grains seems pretty stable and is within my original goal velocity.
Thank you!

 

[smokey3]

Is there any reason not to load 5 right in the middle of that bottom node as well? Around 81 grains seems pretty stable and is within my original goal velocity.
Thank you!

Just my experience and my opinion but most folks tend to get their best accuracy on the higher end and nearer to full 100% capacity of the case fill. Look up your caliber on the Nosler Reloading site, it's free on the internet and see what they say is the most accurate powder charge for your components, they are hardly ever wrong IME. Let us know what you end up with, good luck.
Edit to add they do not list the H1000 powder for that caliber.

 

[eod.tek]

Just my experience and my opinion but most folks tend to get their best accuracy on the higher end and nearer to full 100% capacity of the case fill. Look up your caliber on the Nosler Reloading site, it's free on the internet and see what they say is the most accurate powder charge for your components, they are hardly ever wrong IME. Let us know what you end up with, good luck.
Edit to add they do not list the H1000 powder for that caliber.

I've definitely heard that about close to 100% case fill before, I based a lot of my starting data on both posts here and a forum member who ran all of my components in quick load. 81 grains is about 92.5% fill, and it seemed like most people with similar setups said they experienced the first signs of pressure between 83 and a half and 84 grains, which fall around 95 and 96% case fill, I just didn't want to spend a ton of time messing around looking for pressure signs if it wasn't necessary, which is why the 81 grain load was so tempting.

 

[eod.tek]

Great advice from everybody so far, thank you! Some follow up:

Based on lots of great feedback I loaded up some three shot groups and went back out today because the weather wasn't awful (still a bit windy, but manageable). Shots are all at 100 yards.

1st group was at 81gr (it was actually 5 shots, I had two more I loaded up to warm up the barrel/make sure my magnetospeed was reading (I used the wiser precision mount today to keep it off the barrel)).
Results:
1.33" (I know I threw the last one, I rushed the trigger pull because the wind was picking up fast, if I eliminated that 5th shot its a .87")
SD: 6.7
ES: 19
Average Velocity 2894

2nd group was 82 grains
1.01"
SD/ES inconclusive because this magentospeed hates me

3rd group was 83.1 grains
.246"
SD: 9.6
ES: 19
Average Velocity 2956

Judging by todays results, that 83.1 grains is the load Im going to stick with and try shooting for a large shot count group.

Also, for context I shot the 82.8 again and it was indeed 2931 vs 2934 that I got yesterday, so the magentospeed moving did not effect the actual measured velocity.

 

[Rick Richard]

Great advice from everybody so far, thank you! Some follow up:

Based on lots of great feedback I loaded up some three shot groups and went back out today because the weather wasn't awful (still a bit windy, but manageable). Shots are all at 100 yards.

1st group was at 81gr (it was actually 5 shots, I had two more I loaded up to warm up the barrel/make sure my magnetospeed was reading (I used the wiser precision mount today to keep it off the barrel)).
Results:
1.33" (I know I threw the last one, I rushed the trigger pull because the wind was picking up fast, if I eliminated that 5th shot its a .87")
SD: 6.7
ES: 19
Average Velocity 2894

2nd group was 82 grains
1.01"
SD/ES inconclusive because this magentospeed hates me

3rd group was 83.1 grains
.246"
SD: 9.6
ES: 19
Average Velocity 2956

Judging by todays results, that 83.1 grains is the load Im going to stick with and try shooting for a large shot count group.

Also, for context I shot the 82.8 again and it was indeed 2931 vs 2934 that I got yesterday, so the magentospeed moving did not effect the actual measured velocity.

Now, play with the seating depth some to see if it will tighten up.