Puzzeled by load data.

[Paul5388]

I don't really know how to interpret SD, especially since I hear it isn't really any sort of indication of the accuracy potential.

If the powder you're working with will cooperate and show little gain for an increase in powder, it may be helpful. I've had several Blue Dot loads in .357 that did just that and they were under the published maximum load.

If I load 14.0 gr of SR 4856 behind a 125 gr .357 bullet, the velocity is considerably more (1570 fps) than 13.5 gr (1460 fps) with the same bullet. Would you shoot them based on the chrony information? Well, I've been shooting 14.0 gr for 35 years and that was long before I had a chrony. Of course, I don't shoot that load out of a pot metal, errr alloy gun either.

 

[Skip Sackett]

SR 4856

Paul,

Do you have your glasses on? Either that or you invented a new powder OR had "fat finger disease".

What is it?

As for SD determining accuracy, the fact of the matter is that it can't. Consistency, yes, which SHOULD translate into accuracy, and will if done out of the same chamber, not several as in a revolver.

My thought about it is this: You want the numbers to be as good as can be coupled with accuracy. Velocity, as Paul mentioned, isn't that much of a factor for either one, accuracy or consistency.

With fast powders and low velocities I have seen remarkable numbers and they produced only average accuracy. Of course that is at close range too.


Rifle shooting may be another story all together. Don't know except in the AR platform. If you want one hole groups at 100 yards I would think consistency would play a major factor in that.

FWIW

 

[Wheelgunner840]

Originally posted by OCD1:
I'd like to get a chrono. Is there a good one that is not to expensive? Do you need all kinds of adaptors, stands etc?

You can get a good chrony for right around $100.

I have a "Shooting Chrony" that was just about $100. I have been using it for over ten years. It has the remote read out, so you can get your data at the bench, and not have to strain your eyes to see data on the chrony itself. It is compact enough to fit right in my range bag. I usually just use a small table or a trash barrel with a piece of plywood on top as a place to put the chrony, and place the chrony and barrel out about 10'-15' from where I am shooting. The wire is plenty long enough to reach the read-out that is right next to me.

Mine gives just the data that I need. Velocity (low, high, and average), Standard deviation of the string, and extreme spread of the string. I rely on it constantly when working up new loads. I guess I am one of those reloaders who likes to know what the velocity is of my rounds.

This data is also useful in comparing it to the loads listed in the manuals with regard to pressure. If my manual is saying that a .45ACP 200gr. LSW over 5.0 grs. of W-231 travels at 750 fps and yields 15,000 psi (I am making these numbers up to make my point), and I find that load to be achieving an average of 750 fps, I am pretty cofident that I am within the listed pressure range. I know that is not exact science, as I do not know what kind of barrel they are using, but I think it would be close.

WG840

 

[FrankD45]

Paul and Skip

I agree with your analysis completely. As far as SD goes, I have read in several places, including Lyman #48, that a sharp increase in SD can be an indication of a pressure spike. The operative word is CAN. SD is just another thing to track, along with primers flattening and case head expansion (in a rifle). Of course since I am retired, what else can I do with my time?

Frank

 

[Paul5388]

Errr, I'm not sure if it was phat phinger or something else. Whatever it was, it should have read SR 4756, but I'll leave it alone in the previous post, or no one would catch what you're saying.

As I was looking through several strings I shot with different guns and powders, it seems to me the widest variation is due to differing chambers than anything else.

For instance, my M66 posted a 5 shot string at :
1199
1098
1180
1158
1177

Same gun different lot of powder:
1160
1168
1124
1084
1170

So, there's 2 chambers that seem to produce less velocity that the other 3 chambers and that has absolutely nothing to do with the load itself.

Here's another one from a M625 by chamber with a 230 gr Golden Saber and SR 4756.
1. 1081
2. 998
3. 954
4. 986
5. 1029
6. 1015

Here's a little warmer load (an extra grain of SR 4756) with the same bullet and powder from chamber #1:
1. 1107
1. 1110
1. 1115
1. 1118

This last load converts to 1143 fps MV and 667 ft lbs of ME out of .45 ACP brass, but don't try it in your 1911.

 

[Rule3]

Originally posted by Paul5388:
Errr, I'm not sure if it was phat phinger or something else. Whatever it was, it should have read SR 4756, but I'll leave it alone in the previous post, or no one would catch what you're saying.

As I was looking through several strings I shot with different guns and powders, it seems to me the widest variation is due to differing chambers than anything else.

For instance, my M66 posted a 5 shot string at :
1199
1098
1180
1158
1177

Same gun different lot of powder:
1160
1168
1124
1084
1170

So, there's 2 chambers that seem to produce less velocity that the other 3 chambers and that has absolutely nothing to do with the load itself.

Here's another one from a M625 by chamber with a 230 gr Golden Saber and SR 4756.
1. 1081
2. 998
3. 954
4. 986
5. 1029
6. 1015

Here's a little warmer load (an extra grain of SR 4756) with the same bullet and powder from chamber #1:
1. 1107
1. 1110
1. 1115
1. 1118

This last load converts to 1143 fps MV and 667 ft lbs of ME out of .45 ACP brass, but don't try it in your 1911.

As far as variables go, on your data did you weigh each load individually or are they loaded as what came out of your powder measure? Can there, or is there any variation in perhaps a few grains here or there?

 

[Skip Sackett]

As far as variables go, on your data did you weigh each load individually or are they loaded as what came out of your powder measure? Can there, or is there any variation in perhaps a few grains here or there?

I hate answering for Paul, but it isn't going to stop me from doing it!


No, there is NO possibility of that happening. Not when you charge each cartridge like he does.

Paul, where is that picture of you using the dipper and scale?
I was going to post it here just to prove how you do things and can't find it!

Just trying to help a friend out!

 

[FrankD45]

For what it is worth, I am totally anal when it comes to charging my cases. I have weighed each charge after it drops out of my Dillon powder measure. In fact, I have deliberately set the measure to throw short charges and then trickled enough to bump up to the charge I wanted. (being retired does give us time to waste) In spite of all that I still get similar variations in my chrony data. There are just too many variables.

Frank

 

[Rule3]

Originally posted by smith crazy:

As far as variables go, on your data did you weigh each load individually or are they loaded as what came out of your powder measure? Can there, or is there any variation in perhaps a few grains here or there?

I hate answering for Paul, but it isn't going to stop me from doing it!


No, there is NO possibility of that happening. Not when you charge each cartridge like he does.

Paul, where is that picture of you using the dipper and scale?
I was going to post it here just to prove how you do things and can't find it!

Just trying to help a friend out!

So you are saying he charges each one individually, weighing each?

 

[Skip Sackett]

weighing each?

Yep! !!!!!!!!!

Obviously, he doesn't need a high volume of ammo!

 

[Paul5388]

Skip is right, I weighed each one of those rounds as I normally do.

I did a little housekeeping on my website and now have things categorized a little better. So, the picture you were looking for is in "Reloading", "Reloading Equipment & more" and looks like this.

 

[Rule3]

I use the Lee dippers also but do not weigh each one. I can level them pretty well but do not use a a straight edge so my loads will vary by a few grains high or low. I'm OCD but not that extreme. I have made several dippers for my 380, 9mm and 45. I sanded them down to be in the middle range so to speak so even if I tend to "be a little high I am never over.

Back to the load data here is the response I got back from a e mail to Alliant asking what would be the load for 180gr JHP, using 2400 in 44 Mag. So it's pretty much "about"

"I suggest you start with about 20.5 grs of 2400 and the max should be
about 25 grs. Thanks for your interest in contacting us and have a nice
day."

xxxxxxxxxxxxxx (name and title deleted)
Consumer Service xxxxxxx
Alliant Powder Company