Need Help Analyzing My 1st 6.5CM Load Development Results.

[MNtadpole]

All,

So yesterday I took my Daniel Defense DD5v5 (20" 1:8 twist AR-10) to the local 100 yard range to shoot a series of different charges to find a decent load recipe to go with. I would like to ask for help on analyzing my results, and request some suggestions on what I could do better for next time. Below will you will find both the chronograph data from a magneto speed v3 and the shot groupings from the targets.

First, I want to say that yesterday was really hot (90 degrees) and due to the range closing relatively soon, I was forced to shoot these strings more quickly than I would have liked. I personally believe that the barrel didn't have the ability to adequately cool down between strings because of this.

After looking over the shot results, I felt like the groupings recorded on paper didn't have any obvious results, at least to my novice eyes. I was really hoping to have really tight and really loose groups, which would clearly indicate what loads were best and worst. When I look at them they seem very similar across all shot strings.

Any and all advice and suggestions would be greatly appreciate. THANKS IN ADVANCE!

**load data was used from Sierra**

Cartridge Specs:
-140gr SMKs
-Remington 6.5CM reloaded brass
-Winchester LG rifle primers
-COL: 2.818"
-Powder: Reloder 17. Charges dropped by RCBS Chargemaster @ (34gn, 35.7gn, 37.4gn, 39gn, 40.7gn, 41.5gn, 42.3gn)

Chronograph Data:

 

[BBVDD]

Those are some pretty big jumps in powder charges.
I’d suggest a ladder test 1st to find your nodes, then experiment from there

look at one bullet at each powder charge froM 40-42.5 and bump each 0.2-0.3 grains.

 

[918v]

Play around with 41.5 grains. You have a nice round group with low SD. Play with the COAL plus/minus .005” increments and powder charge plus/minus .1gr increments.

 

[straightshooter1]

All,

So yesterday I took my Daniel Defense DD5v5 (20" 1:8 twist AR-10) to the local 100 yard range to shoot a series of different charges to find a decent load recipe to go with. I would like to ask for help on analyzing my results, and request some suggestions on what I could do better for next time. Below will you will find both the chronograph data from a magneto speed v3 and the shot groupings from the targets.

First, I want to say that yesterday was really hot (90 degrees) and due to the range closing relatively soon, I was forced to shoot these strings more quickly than I would have liked. I personally believe that the barrel didn't have the ability to adequately cool down between strings because of this.

After looking over the shot results, I felt like the groupings recorded on paper didn't have any obvious results, at least to my novice eyes. I was really hoping to have really tight and really loose groups, which would clearly indicate what loads were best and worst. When I look at them they seem very similar across all shot strings.

Any and all advice and suggestions would be greatly appreciate. THANKS IN ADVANCE!

**load data was used from Sierra**

Cartridge Specs:
-140gr SMKs
-Remington 6.5CM reloaded brass
-Winchester LG rifle primers
-COL: 2.818"
-Powder: Reloder 17. Charges dropped by RCBS Chargemaster @ (34gn, 35.7gn, 37.4gn, 39gn, 40.7gn, 41.5gn, 42.3gn)

View attachment 7384095

View attachment 7384096


Chronograph Data:
View attachment 7384093

Those are such large jumps in powder loads that I think you're simply skipping over and round some accuracy nodes. IMHO, I don't think you should be going more than .5 gr increments. I like to go with .3 gr increments start at a seating depth at around max mag or round .020 off the lands.

 

[pell1203]

Try loading three rounds each starting at 40.7 grains to about 43.0 grains in 0.3 grain increments. Shoot them round robin style watching for pressure signs as your powder charge increases. If you start showIng pressure signs stop and don’t shoot any of the higher loads. Go back and shoot your remaining lower load rounds at the appropriate targets and repost your results.

My guess is you will find a node somewhere in the 41.x range and a second node 50-60 fps faster somewhere in the 42.x range. Good luck!

 

[MNtadpole]

Alright, so obviously I'm going to have to revisit load development here. All the above suggestions sound great! Thank you. What are you're thoughts on the barrel heating variable with accuracy here? How long should I be waiting between each string to allow for barrel cooling? Any alternative methods for cooling? It has been so warm here lately, I worry that I would be waiting forever between strings.

 

[BBVDD]

Magnetospeed riflekuhl helps

 

[straightshooter1]

Alright, so obviously I'm going to have to revisit load development here. All the above suggestions sound great! Thank you. What are you're thoughts on the barrel heating variable with accuracy here? How long should I be waiting between each string to allow for barrel cooling? Any alternative methods for cooling? It has been so warm here lately, I worry that I would be waiting forever between strings.

Since I shoot in Arizona around Phoenix, you can imagine how this issue is of concern here is the summer time. So what I do is attach a temperature strip to my barrel just above the receiver and stop firing when the temperature get to 122°F (you can go hotter, but I feel this extends the life of the barrel best). Then, to cool it down I have an insert that uses a battery powered fan (the fan like you see in computers) to blow air from the breach to the muzzle, which cools down the barrel nicely. The more air you can move the faster it'll cool off, so some people get a battery powered mattress inflator and with a plastic tube air is blown from the inflator into the breach and through the barrel. I've even heard of people pouring water down into the barrel and out the muzzle to cool it down really fast.

Barrel Temperature Strips - Pack of 5 or 10 - BarrelCool

Ever wonder what your barrel temperature is? Determine when your barrel is getting too hot with these barrel temperature strips.

barrelcool.com

 

[918v]

I bring a 36v electric shop fan to the range and blow air across the barrel. My barrels never even get warm. Your forend will block a lot of that air but it’s better than nothing. If u got money, buy a second forend and modify it to expose the barrel.

 

[Jordanwickham]

Also with a Magnetospeed, unless you have it on the no barrel mount or a very heavy contour barrel, you are looking at the velocities mainly. You don't want to get really wrapped up in the groupings with it on. So if you are worried about groupings and velocity you would have to load two sets. One for Chrono one for groups.

 

[Dthomas3523]

Even with magneto on a non barrel mount, it will at a minimum move your POI. Typically away from wherever the bayonet is positioned.

When using a magneto, you cannot shoot groups and have 100% reliable data.

And as others have said, your charge weights won’t tell you what you need to know.

 

[Jordanwickham]

Even with magneto on a non barrel mount, it will at a minimum move your POI. Typically away from wherever the bayonet is positioned.

When using a magneto, you cannot shoot groups and have 100% reliable data.

And as others have said, your charge weights won’t tell you what you need to know.

What kind of increments do you run? .5, .3, .2 or based mainly off max powder charge?

 

[MNtadpole]

Even with magneto on a non barrel mount, it will at a minimum move your POI. Typically away from wherever the bayonet is positioned.

When using a magneto, you cannot shoot groups and have 100% reliable data.

And as others have said, your charge weights won’t tell you what you need to know.

You bring up a great point, and I'm going to take it on board for sure. So I understand that the Magnetospeed bayonet would cause a POI shift, but wouldn't that apply to all rounds shot? With that potential being said, wouldn't I still be able to verify grouping "tightness"/closeness even if they were all shifted shifted equally? I guess I just want to make sure I'm looking at the situation in the correct fashion. Thanks!

 

[MNtadpole]

So here are my major take aways here:

1. My powder charges were too gapped, and I need to make small incremental increases...doing ladder testing. Probably do increments of .2-.3 grains.

2. If I'm using my Magnetospeed chronograph, I can only be testing for velocity, not accuracy. So I need to potentially perform two independent tests (one for accuracy and one for velocity).

 

[Dthomas3523]

Couple things. The magneto can loosen or slip, changing where the weight is.

Also, your barrel will react completely different without it on there.

Research barrel tuners. Magneto acts like a tuner, but far less predictable and controlled.

 

[straightshooter1]

So I understand that the Magnetospeed bayonet would cause a POI shift, but wouldn't that apply to all rounds shot? With that potential being said, wouldn't I still be able to verify grouping "tightness"/closeness even if they were all shifted shifted equally?

That's been my experience with my MagnetoSpeed, in that I get very much the same tight groups with it attached as without . . . only I get ~2.5" vertical shift ( MagnetoSpeed being at the 6 o'clock position). So, I happen to find the paper results useful when load developing with it attached. But, as with everything I do, I always verify my results and do so without it attached and if I then feel I need to make some refined adjustments, I do so without it attached (but the other data, like MV's, ES's, SD's on the loads, are all valid).

PS: One reason I might be getting better consistency than other's when using my MagnetoSpeed might be because the break I use does not have ports that flow downward. Just an afterthought here. Though I'm not convinced a break that does or a barrel without a break produces any effect on the flight of the bullet. But I'm pretty sure it DOES act like a tuner since any weight added to the end of the barrel would do so when changing positions on the barrel (forward/backward) would likely act just like a tuner.

 

[MNtadpole]

Couple things. The magneto can loosen or slip, changing where the weight is.

Also, your barrel will react completely different without it on there.

Research barrel tuners. Magneto acts like a tuner, but far less predictable and controlled.

Understood. I can easily see the Magneto slipping and moving!

 

[Jordanwickham]

Understood. I can easily see the Magneto slipping and moving!

Straightshooter1 and you are somewhat correct. In my experience the Magnetospeed hasn't made a decent grouper way worse. It has made a good grouper a little worse, not in overall MOA but it has made a tight grouper with a couple outliers a more dispersed SD group. It has made a bad grouper decent. That's why I say to continue to monitor the groups. My definition of monitor in this instance being to look at it and trend it but don't make any definite group conclusions based on Magnetospeed groups. The first 3 images are 5 shot groups the last 3 are 10 shots in a different barrel (the 42.3 were shot in reverse from what the target says as far as G and C)

 

[Dthomas3523]

What kind of increments do you run? .5, .3, .2 or based mainly off max powder charge?

I don’t care about max charge.

I look up load data and find where I’d like to run and then test in .2 increments 1 grain up and down from there. So basically 2 grains in .2 increments. Once I find my powder and seating node, I’ll then check .1 increments .5 each way. Just to dial it in even more if it needs.

I never run anywhere near max pressure. My outlook is that if I want to run close to max, step up to the next larger cartridge and not have to worry about pressure.

Unless something is a completely new wildcat, there’s so much data online it’s almost pointless to test up to max and then work down since I gave no interest being up there.

 

[Dthomas3523]

Also, I don’t use group size *at all* to determine powder charge. I use chrono exclusively for that.

So when it’s time for groups for seating depth, I’m already done with the chrono. So magneto doesn’t get in my way regardless as when I’m using it, I don’t care about groups and when I’m not using it, I already have all the data I need.

 

[Jordanwickham]

I don’t care about max charge.

I look up load data and find where I’d like to run and then test in .2 increments 1 grain up and down from there. So basically 2 grains in .2 increments. Once I find my powder and seating node, I’ll then check .1 increments .5 each way. Just to dial it in even more if it needs.

I never run anywhere near max pressure. My outlook is that if I want to run close to max, step up to the next larger cartridge and not have to worry about pressure.

Unless something is a completely new wildcat, there’s so much data online it’s almost pointless to test up to max and then work down since I gave no interest being up there.

I guess max charge was a misnomer. I meant the max charge you are wanting to run, like say you are wanting to be somewhere around 42 grains run 1%, .7%, .5% increments from there. How are you finding your powder charge to work from? Finding a couple increments that don't change much and going from there or solely finding one that produces lowest SD and ES and running seating from there?

 

[Dthomas3523]

I guess max charge was a misnomer. I meant the max charge you are wanting to run, like say you are wanting to be somewhere around 42 grains run 1%, .7%, .5% increments from there. How are you finding your powder charge to work from? Finding a couple increments that don't change much and going from there or solely finding one that produces lowest SD and ES and running seating from there?

I usually just stick to .2 because I’m typically in a a 1-2 grain zone. If I were running larger ELR stuff, I’d probably go .3 or .5

 

[MNtadpole]

Also, I don’t use group size *at all* to determine powder charge. I use chrono exclusively for that.

So when it’s time for groups for seating depth, I’m already done with the chrono. So magneto doesn’t get in my way regardless as when I’m using it, I don’t care about groups and when I’m not using it, I already have all the data I need.

First, thank you for all of your input. Second, since you're not using group size to determine powder charge, I assume that you're not just randomly choosing a grain weight...so does that mean you decide on a ballpark velocity. Like say, I just determine for a 6.5CM that 2500fps sounds nice...and find a node around there. Is that what you're chasing?

 

[Jordanwickham]

I usually just stick to .2 because I’m typically in a a 1-2 grain zone. If I were running larger ELR stuff, I’d probably go .3 or .5

Yeah I found on my 7mm Rem Mag anything less than .4 was too narrow of an increment of course that's running mid to upper 60s in grains.

 

[Dthomas3523]

First, thank you for all of your input. Second, since you're not using group size to determine powder charge, I assume that you're not just randomly choosing a grain weight...so does that mean you decide on a ballpark velocity. Like say, I just determine for a 6.5CM that 2500fps sounds nice...and find a node around there. Is that what you're chasing?

Yes. For example, I wanted to run my 6x47 with 109 Bergers around 2950.

So I looked over data and saw most people see that at around 35.0 of varget. I’ll do chrono testing up and down from there. Usually you can find a node within 2 grains or so. Maybe it ends up at 2930 or 2960 when I’m done.

 

[Swamppy]

I don’t care about max charge.

I look up load data and find where I’d like to run and then test in .2 increments 1 grain up and down from there. So basically 2 grains in .2 increments. Once I find my powder and seating node, I’ll then check .1 increments .5 each way. Just to dial it in even more if it needs.

I never run anywhere near max pressure. My outlook is that if I want to run close to max, step up to the next larger cartridge and not have to worry about pressure.

Unless something is a completely new wildcat, there’s so much data online it’s almost pointless to test up to max and then work down since I gave no interest being up there.

Older thread just curious how many rounds do you shoot at each charge weight. How many do you feel you need to shoot to feel confident in the chrono numbers?

 

[MNtadpole]

Older thread just curious how many rounds do you shoot at each charge weight. How many do you feel you need to shoot to feel confident in the chrono numbers?

I know this wasn't directed at me, but I have learned a lot since this original post. For me to trust chrono numbers, I want to see low standard deviations for the given string of rounds of the given charge weight. The lower the SD, the more I can believe that the chrono values are accurate/consistent for that charge. For example, if I shot a string of 5 rounds with an SD of say 4.5, I would feel pretty trusting of the recorded values. In contrast, If I shot a string of 5 rounds and got a SD of say 23.0, I would question the accuracy of my chrono values (not like it's lying, but that I should rely on them)...and probably question my reloading methods.

As far as the secret number goes, I personally would prefer to shoot no less than 4 rounds of a given charge. If those 4 rounds render low SD, I'm good to go. Usually speaking the more rounds the better for statistical data gathering. The quantity of resources available at the time (bullets and prepared brass) typically dictates the number of rounds I can alocate to each charge weight in a ladder test.