.223 Ladder Test

[Old Tanker]

I loaded 10 68g Hornady HPBT Match with CFE.223 at .3g increments. Rifle is a Rem 700 XCR, 26” factory barrel on an Oryx chassis w/bag rider. Bullet was seated .010 off the lands. I use RCBS 1000, balance beam scale cross checked with a digital scale. I start with check weights and make sure both scales weigh the same with each charge change.
Here are the results.
1. 23.5g 2519
2. 23.8 2642
3. 24.1 2631
4. 24.4 2708
5. 24.7 2782
6. 25 2811
7. 25.3 2788
8. 25.5 2886
9. 25.8 2942
10. 26.1 2942

No pressure signs all the way up. ProChrono and rifle were in the shade. What would cause the shot 3 and 7 anomalies? Are shots 9 and 10 the node I’m looking for? Should I load some at 25.9 and 26 and shoot for groups?

 

[chromatica]

I suspect that statistical variation is totally clouding the picture here. How many shots did you make at each charge weight?

 

[DirtySteve]

Chrono error?

 

[LVLAaron]

I don't think those are abnormal at all. You'd think that more powder means more fasterer. I've shot a million ladders / OCW tests and have seen the same thing where you up the charge a bit and the velocity stays the same or goes down a tiny bit.

My money is on, that's where your nodes are.

 

[LVLAaron]

 

[Coyotefurharvester]

Load some on each side of the upper node, see if it is .5-.6 gr wide. And load 4-5 at 24.1 and see if it repeats, just for curiosity, shoot a group. Than a group from the middle of your upper node.

 

[dcali]

Of you shoot enough, you’ll find the “anomalies” go away- it’s just statistical variation.

A proper ladder test plots velocity vs impact height. If you do that, you will see nodes if everything is as it should be. Charge weight is incidental- what you care about it hitting the right velocity for your rifle.

 

[Old Tanker]

I suspect that statistical variation is totally clouding the picture here. How many shots did you make at each charge weight?

Just one. That’s why no ES SD. Since I don’t compete, I’m pretty stingy on what I put down range.

 

[Old Tanker]

It was only 100 so I didn’t do a plot. Faster rounds were on point of aim and slower rounds were right but not much lower. Still nearly a 1” group.

Of you shoot enough, you’ll find the “anomalies” go away- it’s just statistical variation.

A proper ladder test plots velocity vs impact height. If you do that, you will see nodes if everything is as it should be. Charge weight is incidental- what you care about it hitting the right velocity for your rifle.

 

[Ccrider]

May just be odd pieces of brass.

 

[gman47564]

in my opinion your node is between 5 and 8.. i would start with 5 at 25.3 grains and see how they shot... its some where right in there i bet...