Bullet Weight vs Powder Charge: Velocity and SD (Actual Data)

[Subwrx300]

Found a cool way to visualize increasing bullet way and charge weight in Excel data. Shot a bunch of different bullets at various charge weights with known nodes. Then plugged in Velocities and SDs.

This data is for CFE223 in a 224 Valkyrie.

Data/test procedures:

• 26" Rainier +3 gas
• All ammo loaded and fired by me
• Loaded on a Forster Coax Using Redding Competition Dies and RCBS Chargemaster 1500 scale/auto-trickler.
• Labradar chronograph
• 4 shot groups in most cases, however I have data from other tests that lines up with this data.

It's easy to see the SD nodes (Green cells) and how they translate to slightly lower charge as bullet weight increases. Velocity chart has been highlighted with it's SD (Green good for given bullet and red is less good...)

Thought some of you might find it interesting. If you shoot a light bullet through the Charge weight range and then a heavy bullet through it's charge weight range, you can very closely predict any bullet weights in between. I started with 69s, 80s and 88s and guessed at range for 73-77s based on this data. It fell right in line.

What isn't so obvious but is there if you look carefully is that regardless of bullet weight, all nodes happen at the same velocity

• low node of 69gr = high node of 75gr.
• Low node of 75/73 = high node of 80gr
• Low node of 80gr = high node of 88 great

The trick is whether you can get to the node safely. Hope this helps anyone that is trying to understand velocity nodes.

[edited with better image of data]

 

[RackOpsTactical]

Thank you for posting I find this very interesting. Is this excel sheet something you made or found? I do a lot with data analysis for work and my reloading. You would be shocked how many people make decisions based on no data or such limited sampling that its impossible to know if it was correct.

Couple questions come to mind right away. Was all this data shot from your rifle? Was it all out of the same rifle or several? What are the rifle specs? Was all the ammo loaded by you using the same process and methods? What is the sample size of each group (3 shot groups, 10shot groups, etc). What type of chrony did you use and what were the weather conditions?

This info is needed as part of the write up to give all the info to the reader to make the data understandable.

 

[Subwrx300]

Thank you for posting I find this very interesting. Is this excel sheet something you made or found? I do a lot with data analysis for work and my reloading. You would be shocked how many people make decisions based on no data or such limited sampling that its impossible to know if it was correct.

Couple questions come to mind right away. Was all this data shot from your rifle? Was it all out of the same rifle or several? What are the rifle specs? Was all the ammo loaded by you using the same process and methods? What is the sample size of each group (3 shot groups, 10shot groups, etc). What type of chrony did you use and what were the weather conditions?

This info is needed as part of the write up to give all the info to the reader to make the data understandable.

Updated with the details you wanted to see. I made the Excel sheet myself; just a simple matrix/table, nothing fancy.

I loaded all ammo and fired through my rifle. And normally I would have included the details you asked about the first time, but life got in the way. I was busy getting things around for holidays.

Have a good Christmas Holiday everyone!

 

[RackOpsTactical]

Thank you. Was the weather consistent during testing? CfE223 can be impacted by changes in temp.

Also what is your conditional formatting for the good vs bad SD?

 

[lash]

Found a cool way to visualize increasing bullet way and charge weight in Excel data. Shot a bunch of different bullets at various charge weights with known nodes. Then plugged in Velocities and SDs.

This data is for CFE223 in a 224 Valkyrie.

Data/test procedures:

• 26" Rainier +3 gas
• All ammo loaded and fired by me
• Loaded on a Forster Coax Using Redding Competition Dies and RCBS Chargemaster 1500 scale/auto-trickler.
• Labradar chronograph
• 4 shot groups in most cases, however I have data from other tests that lines up with this data.

It's easy to see the SD nodes (Green cells) and how they translate to slightly lower charge as bullet weight increases. Velocity chart has been highlighted with it's SD (Green good for given bullet and red is less good...)

Thought some of you might find it interesting. If you shoot a light bullet through the Charge weight range and then a heavy bullet through it's charge weight range, you can very closely predict any bullet weights in between. I started with 69s, 80s and 88s and guessed at range for 73-77s based on this data. It fell right in line. View attachment 6991151

What isn't so obvious but is there if you look carefully is that regardless of bullet weight, all nodes happen at the same velocity

• low node of 69gr = high node of 75gr.
• Low node of 75/73 = high node of 80gr
• Low node of 80gr = high node of 88 great

The trick is whether you can get to the node safely. Hope this helps anyone that is trying to understand velocity nodes.

[edited with better image of data]

This is a great short study. It seems to support both the OCW concept of optimal barrel time (matching velocities) and the Satterlie velocity only testing. It’s probably too limited to completely be used as support for either method, but certainly seems to do so anyway.

The velocity nodes are very interesting. Thanks for doing and posting this.

 

[Subwrx300]

Thank you. Was the weather consistent during testing? CfE223 can be impacted by changes in temp.

Also what is your conditional formatting for the good vs bad SD?

Weather was 30-35 deg for all ammo except 95SMK (shot at 75 deg). I've found CFE to move about .7FPS per degree. The 88 ELD load (25.4gr) has been fired at temps from 10Deg through 85+deg. Min velocity avg 2670 and max of 2720 for 10 shot strings.

The conditional formatting is manually created. I'll find the rules and post them later. But roughly 8SD low, 15 median, 20 max for 3-gradient scale.

 

[Subwrx300]

This is a great short study. It seems to support both the OCW concept of optimal barrel time (matching velocities) and the Satterlie velocity only testing. It’s probably too limited to completely be used as support for either method, but certainly seems to do so anyway.

The velocity nodes are very interesting. Thanks for doing and posting this.

Yeah I've been wanting to do it for a while. I want to repeat the test with another powder in same caliber (224V) so there is a straight test to see if same thing applies to non-ball powder (R15, R17, Varget etc) problem is I'd prefer it be a non temp sensitive powder (H4350/Varget) but those have proven to be much lower velocity.

Ideally, if I can find a similar stick powder that can get to near the same velocity, I could test whether velocity nodes & ranges stay they same across powders. If that were true, would be easy to home in on a load for a given weight that will likely have good SD.

Some issues with the current data set are 4-shot groups (not ideal but 5-7 shot groups are double the time mainly due to barrel heat) and cold temps. Using ball powder in cold temps can be tricky with standard primers. Ive found randomly fast/slow shots occur more when I set ammo on frozen ground vs padded surface.

I want to repeat with either Varget or H4350 or XBR8208. Just need to see how many rounds I can load and still use the same lots of bullets to keep variables low.

 

[spife7980]

I haven’t done it that comprehensively but it always seems like 23.6-23.8 gr of 8208 in a 223 almost always ends up being my recipe no matter the bullet.

 

[Subwrx300]

I haven’t done it that comprehensively but it always seems like 23.6-23.8 gr of 8208 in a 223 almost always ends up being my recipe no matter the bullet.

I think 8208 or maybe Varget may be the powder I end up testing next. They are short cut stick powders with slightly faster burn rates than CFE223. I'm trying to remove temps as variable so leaning more towards Varget due to better temp sensitivity (in my experience) of around .3 fps per degree.

 

[lash]

I’ve found that for .260 and any projectile in the 130-142 range, it’s a safe bet that you’ll find something good in the 41.5-42.5 range using H4350. Most likely closer to 41.8-42.2. Usually not the highest node, but almost always a stable and forgiving node.

 

[lash]

I think 8208 or maybe Varget may be the powder I end up testing next. They are short cut stick powders with slightly faster burn rates than CFE223. I'm trying to remove temps as variable so leaning more towards Varget due to better temp sensitivity (in my experience) of around .3 fps per degree.

I’ll be interested to see your results using Varget in .224V, especially with the 88g.

 

[Subwrx300]

I’ve found that for .260 and any projectile in the 130-142 range, it’s a safe bet that you’ll find something good in the 41.5-42.5 range using H4350. Most likely closer to 41.8-42.2. Usually not the highest node, but almost always a stable and forgiving node.

100% Agreed. I've loaded for 5 different 6.5CM barrels and all of them were best within +-.2 of 42gr H4350, including the Criterion I'm shooting now which shoots 123SMKs, 130Hybrids, 140 VLDs and 140 ELDs at 42gr with .6 or better precision at that charge.

But I the interesting part is this: for a given charge weight (say 42gr), most bullets seem produce the same speed regardless of bullet weight. 140s and 123s both produce 2780-2800fps at 42gr in my barrel. However, I can safely increase the charge for the 123s but would be struggling to go much higher with the 140s without seeing pressure.

 

[Subwrx300]

I’ll be interested to see your results using Varget in .224V, especially with the 88g.

That clinches it! I'll be using Varget. Probably the most common powder for 223s and not a ton of data for Varget with the 224V.

If I repeat this test, I am not sure it makes sense to do such short windows for load increment. I don't have much prior data, whereas with prior test, I was able to draw on several hundred rounds of load testing to develop a hypothesis to test.

With Varget, I really don't have the same data, so I am thinking of designing this one slightly differently: shooting 3 rounds per charge (rather than 4) but test wider range of charges. The issue is keeping the velocity change per charge around 15-20fps max. With CFE its about .1-.2 gr increments to create good resolution. With Varget, it seems slightly more (.2-.3) because you get less added velocity per grain.

So my thought is to shoot at .2 intervals but with 6 charges per bullet rather than 4 charges tested above. Trouble is getting them to overlap so bullets can be compared to one another.