Load development.....opinions??

[FURMAN]

See my earlier post in this thread. Fact- not all loads with small es and sd will be accurate period. Fact- not all accurate loads will have small es and sd period. If you want an accurate and forgiving load you need to do load development on paper at the max distance you intend to shoot.

 

[User4302021]

Dog rocket, thanks for the input! curious why you think the flat spot concept is nonsense? In my head, getting into the middle of a range of charges that doesnt show much change of velocity, would be somewhat forgiving of temp swings, scale variance etc, etc. Similiar to a range of charges that have a consistant poi. Should be a "forgiving" load???

There is a range where the loads act like that, but it is nearing max pressure where you are reaching diminishing returns. That usually takes place at about 3%-1% off of maximum. Until the powder reaches optimal pressure it is somewhat erratic. Any flat spot is just an coincidental artifact of overlapping extreme spreads from one increment to the next.

 

[Mikecr]

'Forgiving' is separate and different from 'accurate'.
With this, I assign zero faith in OCW.

 

[FURMAN]

Most ladders I do have a very large node where bullets impact the target with very tight vertical over .5-1 grain powder charge. Sometimes that window is smaller and I will not run that combo. USUALLY the OCW will show this same response. A few times I have run the OCW and every single powder charge over 3-4 grains caused the bullets to impact the target at the same point. In those cases tests had to be repeated with a ladder. I have on several occasions performed a ladder and OCW because I didn't originally believe the OCW was a valid method. I would say the OCW works in every case except when it shows that every single load is the same. I have yet to find an instance when then OCW was performed with groups shifting, then the shift stops, then it starts again where the groups with the same point of impact did not repeat the exact response in a ladder test. Some rifle and load combos will be more forgiving than others but I would never run a load that was on the edge of a scatter node even if it were more accurate.

 

[User4302021]

Most ladders I do have a very large node where bullets impact the target with very tight vertical over .5-1 grain powder charge. Sometimes that window is smaller and I will not run that combo. USUALLY the OCW will show this same response. A few times I have run the OCW and every single powder charge over 3-4 grains caused the bullets to impact the target at the same point. In those cases tests had to be repeated with a ladder. I have on several occasions performed a ladder and OCW because I didn't originally believe the OCW was a valid method. I would say the OCW works in every case except when it shows that every single load is the same. I have yet to find an instance when then OCW was performed with groups shifting, then the shift stops, then it starts again where the groups with the same point of impact did not repeat the exact response in a ladder test. Some rifle and load combos will be more forgiving than others but I would never run a load that was on the edge of a scatter node even if it were more accurate.

The only problems with the OCW and ladder test are:
A) The shooter needs to actually be able to shoot well enough to be consistent.

B) The shooter needs to know how to read the test! Most don't have any idea what they are looking at.

 

[FURMAN]

The only problems with the OCW and ladder test are:
A) The shooter needs to actually be able to shoot well enough to be consistent.

B) The shooter needs to know how to read the test! Most don't have any idea what they are looking at.

100% agreed but if you're going to be shooting game long range you owe it to the animal.

 

[willyqbc]

Dog rocket...so during load development, what are your "indicators" that youve reached the optimal pressure range you mentioned? Is it common point of impact from one charge to the next? Or are you looking for something more than that, or something entirely different?

Thanks again all! All very good food for thought!

 

[User4302021]

Dog rocket...so during load development, what are your "indicators" that youve reached the optimal pressure range you mentioned? Is it common point of impact from one charge to the next? Or are you looking for something more than that, or something entirely different?

Thanks again all! All very good food for thought!

1) When the powder starts burning clean and leaving little residue on the necks for one indicator. Also the powder ring on the neck moves off the shoulder to just short of the neck / shoulder junction.
2) Because pressure testing has been done at the factory, I know what velocity range I should be seeing for a given charge weight (adjustments made for barrel length), so that is a clue.
3) I measure case heads using a micrometer, so when case heads expand to full chamber diameter after firing is another clue.
4) If doing an OCW test, there is most often a major POI shift as the charge weight moves into the optimal burn rate. It stays constant until you get into over pressure when it likely shifts again and starts to go crazy.

 

[Mikecr]

OCW does not even include seating, which is the single largest adjustment to accuracy.
Seriously, you can't load develop with powder alone. You will never reach most accurate with a chronograph alone.

 

[FURMAN]

I would agree seating depth testing must be done to achieve the most accuracy but every ladder test I have ever done would disagree with it being the most important aspect. Powder charge is what removes most, if not all, of the vertical at long distance. Seating depth can then be tuned to make the group round or remove the horizontal. I could not care which is done first but every single time I have done a ladder powder charge has a much larger effect.

 

[User4302021]

OCW does not even include seating, which is the single largest adjustment to accuracy.
Seriously, you can't load develop with powder alone. You will never reach most accurate with a chronograph alone.

Which is why I have largely abandoned the OCW. However, it can still be useful as a crude indication of the charge range you should be in when you start seating depth testing. OCW is fairly useful at mapping gross differences in barrel movement, but it is seating depth that fine tunes it.

EDIT:
For my own personal practice, I have short cut the process. I choose a charge that puts me 2% off maximum for my rifle / load combination and just adjust seating depth till it dials in and call it good. Why 2 percent? Because it is most often in the middle of the optimal burn rate, gives good load density, good velocity, and is just enough to keep me out of heat trouble in the summer.

If it dials in, I'm golden. If it doesn't, I might try shifting the charge 0.3 grains up or down depending on what I am seeing, but usually I just try something else. Experience has shown me that if nothing shows up as promising using this short process, then this combo probably isn't worth chasing.

 

[willyqbc]

For my own personal preference, I have short cut the process. I choose a charge that puts me 2% off maximum and just adjust seating depth till it dials in and call it good.

Interesting.....might have to try that on a 264wm that is being built as we speak! I assume your just working up a quick ladder of charges, looking for ejector marks, heavy bolt lift etc? Or just dropping 2% from book max?

Seriously, you can't load develop with powder alone. You will never reach most accurate with a chronograph alone.

I usually use powder charge to try and find a 1/2 grain or more range that seems to have consistant velocity, and poi across the powder range. once I select a charge to use, I fine tune group size by adjusting seating depth.

Be very interesting to try out dogrockets method....if its repeatable across multiple rifles, it would certainly be a very nice shortcut to get to a charge selection!

On a side note....this is why forums like this are great!!! Generate a conversation, and there is always little nuggets of wisdom to be collected, and new ideas to try!
Many ways to skin a cat......... 42 minds are better than 1!!

Chris

 

[User4302021]

I assume your just working up a quick ladder of charges, looking for ejector marks, heavy bolt lift etc? Or just dropping 2% from book max?

No, not from the book. I find the maximum for my rifle/load combination using a short ladder. Two rounds per charge across the magnetospeed, looking at the clues I talked about in post #36.

 

[willyqbc]

Good deal! Thanks DR! Gonna give that method a try!