Which powder charge do I choose…

[Rickyd]

I have been out today testing different powder charge of n555, I’m really happy with the results, seating depth has been kept the same throughout the test- that’s the next process after deciding a load. There are no pressure signs throughout the testing, so all good in that department. My question is, what charge would you choose? At 44g the extreme spread and standard deviation is at its lowest, however, I’m thinking of choosing 43.7g as the velocity doesn’t seem to jump much at all between 43.6-43.8, and the extreme spread and standard deviation is pretty good- just not as good as @ 44g

[furrybean]

0.1 is too little a change

If it comes in and out of node in 0.1 its not a solid load

[Scotch_egg]

10 hours ago, Rickyd said:

I have been out today testing different powder charge of n555, I’m really happy with the results, seating depth has been kept the same throughout the test- that’s the next process after deciding a load. There are no pressure signs throughout the testing, so all good in that department. My question is, what charge would you choose? At 44g the extreme spread and standard deviation is at its lowest, however, I’m thinking of choosing 43.7g as the velocity doesn’t seem to jump much at all between 43.6-43.8, and the extreme spread and standard deviation is pretty good- just not as good as @ 44g

I’m thinking of choosing 43.7g as the velocity doesn’t seem to jump much at all between 43.6-43.8
 

Test again and use 5 rounds. I know what @furrybeanmeans, when testing you didn’t need to work up in .1 grains and could have shot less to get the same result. But as it is, you have identified a node. Now more shooting 😁

[Popsbengo]

Shooting three shot groups is pretty much meaningless statistically.  I bet if you shot the same strings again under the same conditions you will see different results.

[No i deer]

Shoot 2 groups of each to see if it's repeatable 

[Simonc65]

I’ve been watching @WitchDoctorPrecision on YouTube, don’t let the silly name put you off, he’s one of the best YouTubers I’ve seen for collecting statistically relevant samples of data & only testing one thing at a time I’ve seen, his data is still limited, but way better than others I’ve seen !!

I’d suggest either his primer weight tests or primer seating death tests ones to see how to run a good statistical test, it takes a lot of ammo though 🙄

 

 

[Popsbengo]

6 minutes ago, Simonc65 said:

I’ve been watching @WitchDoctorPrecision on YouTube, don’t let the silly name put you off, he’s one of the best YouTubers I’ve seen for collecting statistically relevant samples of data & only testing one thing at a time I’ve seen, his data is still limited, but way better than others I’ve seen !!

I’d suggest either his primer weight tests or primer seating death tests ones to see how to run a good statistical test, it takes a lot of ammo though 🙄

 

 

And Bryan Litz, Jeff Siewert et-al

[Catch-22]

Agreed, 0.1gn is far too granular for a medium sized case like the 6.5Creed.

If you say you have no pressure signs, I say you need to keep going up until you start to see pressure. Know your maximum, focus on nodes with good ES/SD below your max and don’t exceed it.

From your numbers, I think you’re at or just under a good node. It seems fairly stable at your top end, so keep going and see what the numbers show you.

[Popsbengo]

1 hour ago, Catch-22 said:

Agreed, 0.1gn is far too granular for a medium sized case like the 6.5Creed.

If you say you have no pressure signs, I say you need to keep going up until you start to see pressure. Know your maximum, focus on nodes with good ES/SD below your max and don’t exceed it.

From your numbers, I think you’re at or just under a good node. It seems fairly stable at your top end, so keep going and see what the numbers show you.

I respectfully disagree.  0.1 grain increments are fine, shoot sufficiently meaningful groups to home in on a group and then tweak seating depth to finalise best groups.

NRA (USA) recommend 5 x 5 groups of each load overlaid to give a 25 shot statistically meaningful group pattern.  It's only 5 per group per target as otherwise one would be shooting through a hole and gaining no information.   I know it's expensive in terms of ammo and barrel life - isn't that why we kid ourselves that a three shot group will do?

My method is to make as precise a batch of ammo as I can manage and then use an economic approximation of the above.   I shoot some five shot groups and quickly discard obviously bad loads,  then shoot some more groups of five around what appears to be a good load to confirm - then play with seating in 5' steps (finer with VLD).   I get pleasing results at 500 - 1000 and ELR distances.   Maximum velocity "node" is not my objective,  accurate and precise groups are.  I'm only interested in MV at the end of my process so I can set up my ballistic app.

 

[Rickyd]

7 hours ago, Scotch_egg said:

I’m thinking of choosing 43.7g as the velocity doesn’t seem to jump much at all between 43.6-43.8
 

Test again and use 5 rounds. I know what @furrybeanmeans, when testing you didn’t need to work up in .1 grains and could have shot less to get the same result. But as it is, you have identified a node. Now more shooting 😁

Would you say 43.7 is the way to go? Even though I haven’t yet seen pressure signs I don’t really want to go any higher as the case looks pretty full as it is now.

[Catch-22]

4 hours ago, Popsbengo said:

I respectfully disagree.  0.1 grain increments are fine, shoot sufficiently meaningful groups to home in on a group and then tweak seating depth to finalise best groups.

NRA (USA) recommend 5 x 5 groups of each load overlaid to give a 25 shot statistically meaningful group pattern.  It's only 5 per group per target as otherwise one would be shooting through a hole and gaining no information.   I know it's expensive in terms of ammo and barrel life - isn't that why we kid ourselves that a three shot group will do?

My method is to make as precise a batch of ammo as I can manage and then use an economic approximation of the above.   I shoot some five shot groups and quickly discard obviously bad loads,  then shoot some more groups of five around what appears to be a good load to confirm - then play with seating in 5' steps (finer with VLD).   I get pleasing results at 500 - 1000 and ELR distances.   Maximum velocity "node" is not my objective,  accurate and precise groups are.  I'm only interested in MV at the end of my process so I can set up my ballistic app.

 

Each to their own.

I still think starting your tests with 0.1gn increments in a case that size is just a waste of components. 
Personally I’d be going up in 0.3gn increments and looking for the stable nodes. Then you can fine tune between the node with 0.1gn charges to find that optimum within the node.

Obviously fine tune the load with seating depth and possibly neck tension, if you need to.

And my suggestion to find your max pressure isn’t an attempt to ‘see how hard I can push this bullet’, but rather understand where the pressure is for your gun. Depending on your components, and how they perform in your country’s weather conditions, you won’t really know when you might hit over pressure. Without knowing your upper limits, you are merely hoping and praying you don’t hit it sometime and have a bad day.

I agree that you should be choosing a node based on stability and also accuracy with repeatable results. I don’t mind if that happens to be a low node. But I still like to know where my max is so I don’t get into trouble!

[furrybean]

1 minute ago, Catch-22 said:

Each to their own.

I still think starting your tests with 0.1gn increments in a case that size is just a waste of components. 
Personally I’d be going up in 0.3gn increments and looking for the stable nodes. Then you can fine tune between the node with 0.1gn charges to find that optimum within the node.

Obviously fine time load with seating depth and possibly neck tension if you need to.

Agreed 

There are many ways to skin a cat. 0.1 will work if you want to shoot that many rounds 

I wouldn’t, I’d do as you say, find an area of potential and then try around there 

[snakeman]

2 minutes ago, Catch-22 said:

I still think starting your tests with 0.1gn increments in a case that size is just a waste of components. 
Personally I’d be going up in 0.3gn increments and looking for the stable nodes. Then you can fine tune between the node with 0.1gn charges to find that optimum within the node.

+ 1

[Jjason]

Ohh great 

[Re-Pete]

And don't forget your neck tension......🙂

Pete