Optimal Charge Weight Help

[Radosilver]

I have a question on optimal charge weight. Based on the info below, would you abandon this powder and move on to another powder for load development, or is there something I am missing that maybe would make it worth sticking with testing?

This if my first attempt at testing like this, so if I'm overlooking something obvious my apologies. But, I shot 10 singles at 100 yards out of my .300 Win yesterday in an attempt to locate a group of 3 or so shots close to each other that would give me a starting point for trying to find the optimal charge weight for my rifle with IMR-7828SSC. I posted a pic below. The 3 fouling shots are marked F1. The others are marked with the charge weight. The charge weight spread was from 69.2 gr to 73.7 gr. As you can see from the pic, there doesn't appear to be a range of powder charge with the impacts close to each other. The muzzle velocity also seemed to jump around a lot too rather than a steady increase as the charge weight went up. Maybe that's normal. The bullet is a ELD-X 212 grain if that factors in. Thanks.

 

[EdP]

I don't feel like you have particularly meaningful data. What I suggest is to get a real target, the type with 5 bullseyes. I personally like the ones with diamond bullseyes because I can line up the diamond points with the crosshairs. Shoot groups of 5 shots of the same charge, 3 minutes between shots in a group, and over a chronograph. If you have cleaned the barrel before starting shoot a round or two before shooting for groups and do the same 3 min cooldown between shots. Don't be surprised if your POI changes a bit with different charges. Then look at your groups and your statistics to see what is happening. I find that the best stats don't always correspond to the best groups, but bad stats don't ever yield good groups. This is the method that yields data I can work with and get good results. Others have different methods that work for them and perhaps they can give you a better read on the data from your range session.

 

[Pickettpuncher]

If you are looking for bullets that group together, you need to do this test at 300 and not at 100.

 

[Pickettpuncher]

You’re also working with .5 grain increments best I can tell. .3 is better.

 

[Rifles And More]

A chronograph would tell you what you want without looking at the target. Find the rounds with similar velocities, load a few more and verify.

 

[Rifles And More]

I'll add some more...

What you are looking for needs to be done at farther yardages.

At 100 yards I've seen a horizontal line drawn and targets dots place along it. Fire one round at each dot and look for the rounds that rounds that are above/below the line on the same plane.

Hard to explain...

 

[Pickettpuncher]

A chronograph would tell you what you want without looking at the target. Find the rounds with similar velocities, load a few more and verify.

This is also known as the satterlee test. I’ve tried it a few times with mixed results, but is another way to test without extended ranges

 

[Pickettpuncher]

I'll add some more...

What you are looking for needs to be done at farther yardages.

At 100 yards I've seen a horizontal line drawn and targets dots place along it. Fire on round at each dot and look for the rounds that rounds that are above/below the line on the same plane.

Hard to explain...

This was vaguely explained to me a few weeks ago. Basically each round is fired and as you go thru the progression the bullet should hit in the same general area. When that area changes, the node changed. I’m sure there’s a lot more to it than that, but it made sense.

 

[Rifles And More]

This is also known as the satterlee test. I’ve tried it a few times with mixed results, but is another way to test without extended ranges

Sure is.

I've switched over to it and had good luck so far. If nothing else it takes reading the chicken bones of a target out of the mix for me. I don't look at target until i do seating depth.

 

[Pickettpuncher]

Sure is.

I've switched over to it and had good luck so far. If nothing else it takes reading the chicken bones of a target out of the mix for me. I don't look at target until i do seating depth.

Might be what I’ll start doing.

 

[Cahunter805]

Like stated above you should shoot this type of test at a minimum of 300 yards. looking at that target I would load 3 shot groups from 69.7-71.7 and shoot them at 300 if you want to stick with this powder.

 

[Radosilver]

Thanks for the pointers. I did shoot each round through a chrono with the following results if that is helpful:

69.2 gr = 2,822
69.7 gr = 2,804
70.2 gr = 2,860
70.7 gr = 2,909
71.2 gr = 2,920
71.7 gr = 2,884
72.2 gr = 2,918
72.7 gr = 2,990
73.2 gr = 3,004
73.7 gr = 2,991

Not sure that I want to stick with this powder or try something else. For the sake of doing it I shot a couple 3 shot groups with IMR-4350 at different powder charges just to see what it would do and because I had it around. They both grouped right at 3/4". The velocity was 2,860 avg with a spread of 47 fps at 65.0 grains and 2,913 avg with a spread of 13 fps at 65.0 grains. Mainly just trying to figure out whether I should keep messing with the 7828 or move on to something else.

 

[EdP]

I also don't try to find an optimum powder charge until I've done testing to find a seating depth the bullet-rifle combo likes. If you are not going to go thru that process and just use a book COAL, go ahead and work up a charge. If you change seating depth after developing a charge it will likely change your velocity, perhaps to outside the node, but you will at least know the desired velocity if you did your shooting over a chronograph.

 

[Rifles And More]

Thanks for the pointers. I did shoot each round through a chrono with the following results if that is helpful:

69.2 gr = 2,822
69.7 gr = 2,804
70.2 gr = 2,860
70.7 gr = 2,909
71.2 gr = 2,920
71.7 gr = 2,884
72.2 gr = 2,918
72.7 gr = 2,990
73.2 gr = 3,004
73.7 gr = 2,991

Not sure that I want to stick with this powder or try something else. For the sake of doing it I shot a couple 3 shot groups with IMR-4350 at different powder charges just to see what it would do and because I had it around. They both grouped right at 3/4". The velocity was 2,860 avg with a spread of 47 fps at 65.0 grains and 2,913 avg with a spread of 13 fps at 65.0 grains. Mainly just trying to figure out whether I should keep messing with the 7828 or move on to something else.

Highlighted above is where I'd explore some more.

 

[Radosilver]

I also don't try to find an optimum powder charge until I've done testing to find a seating depth the bullet-rifle combo likes. If you are not going to go thru that process and just use a book COAL, go ahead and work up a charge. If you change seating depth after developing a charge it will likely change your velocity, perhaps to outside the node, but you will at least know the desired velocity if you did your shooting over a chronograph.

Thanks. I was debating which to do first. This might be a dumb question, but I'm new to this, so how do you choose the powder load you use to test seating depth?

 

[Radosilver]

Highlighted above is where I'd explore some more.

Thank you

 

[Rifles And More]

Thanks. I was debating which to do first. This might be a dumb question, but I'm new to this, so how do you choose the powder load you use to test seating depth?

Just find a safe middle of the road charge.

I have not found that seating depth knocked me out of a powder node. I usually do powder first then seating depth. I also wondered about it changing, but after experimenting I have yet to see it.

 

[35WhelenAI]

What is your primer for these loads?

 

[Radosilver]

What is your primer for these loads?

Winchester WLRM

 

[35WhelenAI]

That's a good magnum primer.