Why the huge discrepancy between load sources?

[LocoGringo]

Ok, as an update, I decided to test my loads today. It was a dreary day, but not very cold (around 50 degrees) and the "rain" was more like a drizzle if anything was falling. Certainly not ideal conditions, but tolerable.

Primers in all test cases look normal. Bolt lift was easy and consistent on all loads, so whatever the pressure limit is on this rifle, I don't think I got close to it. The most potential seemed to be around the 41.5-42.0 mark. The tightest group was .623" 4-shot at 41.5 grains. I did allow for cooling between 5-shot strings.

So my plan for the next test rounds is to load 10 rounds each of 42.1, 41.9, 41.7, 41.5 and 41.3 grains of Varget and maybe load a little closer to the lands like around .020 or .030 off rather than the .050 off like I was trying. What do y'all think? I'm wide open to suggestions.

 

[ballman6711]

Make one change at a time. Do your powder charge range, seated to the same depth as previous rounds. Find the load you want to use, and then load a few of those at different seating depths.

Someone with more experience will be along to correct me if I'm wrong.

chris

 

[irishlad]

If any of you internet forum experts want to challenge this, please provide the pressure data Hornady used for their loads.

We don't need no stinking internet forum experts, we got you!

 

[jmr40]

Three reasons.

If NEW load data shows a lower powder charge it is most likely because modern pressure testing methods are more accurate. Old loads that were once thought to be safe may never have been.

If the NEW data shows a heavier powder charge it could also be because modern pressure testing methods are more accurate. It could also be because whoever tested that data simply stopped testing at a certain point. When you see max loads listed that may or may not be the true max safe load. Someone else may have come along later and did further testing to determine more powder was still safe.

Years ago, there was very little difference between bullets. A common cup and core 150 gr bullet made by Winchester, Remington, Hornady, Sierra, or anyone else was similar and load data was interchangeable. Today's premium bullets can be very different in bullet shape and composition. A 180 gr RN bullet will have much more bullet in contact with the barrel than a very high BC 180 gr bullet and max load data should be different.

 

[AJC1]

Ok, as an update, I decided to test my loads today. It was a dreary day, but not very cold (around 50 degrees) and the "rain" was more like a drizzle if anything was falling. Certainly not ideal conditions, but tolerable.

Primers in all test cases look normal. Bolt lift was easy and consistent on all loads, so whatever the pressure limit is on this rifle, I don't think I got close to it. The most potential seemed to be around the 41.5-42.0 mark. The tightest group was .623" 4-shot at 41.5 grains. I did allow for cooling between 5-shot strings.

So my plan for the next test rounds is to load 10 rounds each of 42.1, 41.9, 41.7, 41.5 and 41.3 grains of Varget and maybe load a little closer to the lands like around .020 or .030 off rather than the .050 off like I was trying. What do y'all think? I'm wide open to suggestions.

I think you should pick a sound load development process and follow it to the best of your ability. You will end up with results and brackets that have much higher tolerance to temperature and seating depth variations.

 

[Varminterror]

What do y'all think?

With all due respect, reading the last - I can’t help but think, in your shoes, I would follow proven load development methods, and absolutely ignore “the smallest group” which coincidentally struck one particular charge weight, because I would acknowledge no proven development method is determined by small shot count, singular group sizes.

 

[film495]

seems good to me. what is your goal? smallest group possible? or just a solid consistent load?

 

[LocoGringo]

I think you should pick a sound load development process and follow it to the best of your ability. You will end up with results and brackets that have much higher tolerance to temperature and seating depth variations.

Ok, sounds good, but maybe I don't know enough. I'm open to suggestions to a "sound load development process". My process is to start low and load 5-10 rounds and shoot groups. When a small group shows up, I focus and refine around that loading to see if it is consistent and, possibly, the "size" of the node. My overall goal is a small, precise group that is repeatable. After I have the small, consistent groups, I chronograph to develop a ballistics chart. I've not had anyone explain a different method to me, but I'm open to other approaches. I don't have a lot of expensive instruments and gauges and I'm pretty sure my chronograph is fairly inexpensive (it was a gift from my dad a long time ago).

With all due respect, reading the last - I can’t help but think, in your shoes, I would follow proven load development methods, and absolutely ignore “the smallest group” which coincidentally struck one particular charge weight, because I would acknowledge no proven development method is determined by small shot count, singular group sizes.

No disrespect taken. I'm here to learn and open to suggestions for proven load development methods. Please do explain what I'm doing wrong or suggest alternatives. I don't have a mentor to show me.

 

[AJC1]

Ok, sounds good, but maybe I don't know enough. I'm open to suggestions to a "sound load development process". My process is to start low and load 5-10 rounds and shoot groups. When a small group shows up, I focus and refine around that loading to see if it is consistent and, possibly, the "size" of the node. My overall goal is a small, precise group that is repeatable. After I have the small, consistent groups, I chronograph to develop a ballistics chart. I've not had anyone explain a different method to me, but I'm open to other approaches. I don't have a lot of expensive instruments and gauges and I'm pretty sure my chronograph is fairly inexpensive (it was a gift from my dad a long time ago).

No disrespect taken. I'm here to learn and open to suggestions for proven load development methods. Please do explain what I'm doing wrong or suggest alternatives. I don't have a mentor to show me.

This is just one of many. Varminterror might like another better.
https://precisionrifleblog.com/2012/07/13/creighton-audette-ladder-testing/

 

[mdi]

Make one change at a time. Do your powder charge range, seated to the same depth as previous rounds. Find the load you want to use, and then load a few of those at different seating depths.

Someone with more experience will be along to correct me if I'm wrong.

chris

No "expert" needed. Excellent development advise. If you changed two or four things during your testing, which item changed the results?

 

[LocoGringo]

Make one change at a time. Do your powder charge range, seated to the same depth as previous rounds. Find the load you want to use, and then load a few of those at different seating depths.

Someone with more experience will be along to correct me if I'm wrong.

chris

I figured me wanting to change 2 of the variables would show my impatience. Of course, you're right.

 

[LocoGringo]

This is just one of many. Varminterror might like another better.
https://precisionrifleblog.com/2012/07/13/creighton-audette-ladder-testing/

If I understood the brief summary, basically just load 20 rounds from low to high in terms of powder charge varying by .2 of a grain and chronograph each shot. After you have all 20 chronographed, look for "flat spots" in the velocity curve and work around those charge weights? As a bonus, you can shoot for groups also, but that is not necessary. Does that sound right using the method you posted?

An additional criteria to look for would be horizontal dispersion versus vertical dispersion. Even if a load is horizontally spread out but its vertical dispersion is good, it has potential?

 

[AJC1]

If I understood the brief summary, basically just load 20 rounds from low to high in terms of powder charge varying by .2 of a grain and chronograph each shot. After you have all 20 chronographed, look for "flat spots" in the velocity curve and work around those charge weights? As a bonus, you can shoot for groups also, but that is not necessary. Does that sound right using the method you posted?

An additional criteria to look for would be horizontal dispersion versus vertical dispersion. Even if a load is horizontally spread out but its vertical dispersion is good, it has potential?

Basically. The unsaid part is your looking for barrel wip timing if I am recalling the right test. Crono data should be coupled with impact placement. The vertical dispersion shows you where in the timing you are and the load will be where charge weights print in groups for vertical dispersion. I take the area of consistent ignition velocity and vertical dispersion and further refine with seating depth. Maybe I am recalling OCW. Then there are spin off names like tall target test. I review the test I want to conduct, make a test box and then review the test just prior to commencement so I actually shoot the test correctly. I favor tests that look at bullet impact over numbers on a chronograph. My normal recommendation is ocw then seating depth, the article I linked is just an example.... find one that you feel best meets your needs and available facilities to conduct.

 

[LocoGringo]

This is just one of many. Varminterror might like another better.
https://precisionrifleblog.com/2012/07/13/creighton-audette-ladder-testing/

He shoots 200 yards, but for keeping track of the impacts, I literally would need to walk the range after every shot and mark it to both remember the impact and allow for cooling of the barrel. Unfortunately, I don't have access to a private 200 yard range where I wouldn't inconvenience every other shooter there. Would 100 yards be sufficient or not?

 

[Varminterror]

Traditionally, the Audette method was done just as the POI analysis because chronographs were not nearly as readily available then as they are today, so the Audette Ladder test involved loading those incremental charge weights and firing at the same POI, and looking for clusters where adjacent charges hit near the same vertical position on the target. The velocity curve portion described in that article has largely been renamed as the Satterlee method.

Dan Newberry’s OCW method is another option which relies upon the same principles as the Audette Ladder - watching for clustering of vertical position, but rather shooting groups at multiple points of aim instead of a single target.

Personally, I absolutely do not trust these POI dependent results at 100yrds. 300yrds is the minimum I will shoot, preferring 600+.

He shoots 200 yards, but for keeping track of the impacts, I literally would need to walk the range after every shot and mark it to both remember the impact and allow for cooling of the barrel. Unfortunately, I don't have access to a private 200 yard range where I wouldn't inconvenience every other shooter there. Would 100 yards be sufficient or not?

I do not find reliable results from these tests at 100yrds.

Color your bullets with multiple markers to identify your shots, and use a spotting scope with a reference target drawing at the shooter position to keep track of which is which. OR, shoot them at multiple points of aim, Newberry OCW style, so you don’t have to worry about forgetting which impact hole is which charge weight.

 

[GooseGestapo]

Part of the issue with Hornady is how they arrive at their published data.
Closely reading their text reveals this:

They work the data up using industry standard methods and pressure levels.
BUT! This isn’t what they publish!
They take the highest charge rounded down to nearest 100fps level, and THIS is what they publish.

If 44.7gr of Varget gives. 2890fps , and 43.5 gives 2,800fps, this is what goes in the column...

I typically use the Powder manufacturers or distributers data as a “guide”. My rifle and components are the final arbiter...

 

[Thomasss]

There are big reasons to answer your question: 1) Powder manufacturers do change their formulas from time to time. for example, my powder is now cleaner burning; my powder is temperature insensitive, my powder has copper cleaner, etc. and those changes in themselves can change your loads.
2) Mfr. change formulas to be cheaper to sell: I have 4064 Dupont powder that is still very good to use from the 1970s, but I also tossed some 4831 Hodgdon powder from 1990 that went bad. This can be a change in their stabilizing agents.
3) The Mfrs. are starting to have specific powders for specific calibers. They are getting away from powder that can be used in many different types of guns, like shotguns, pistols and rifles. (So they can sell more different kinds to you and make more money.)
4) Years ago the NRA and Mfrs. said the you should test every new container of powder you buy. How many people do that?....
5) Unfortunately they do not like to tell you why they changed their recommendations any more. They hide behind liability, but many times, for the above reasons, they don't want you to go back to the old recipes.
Now, are you going to call the "possible bluff" and have possible hot loads or submit to more conservative information and continue to shoot the way they tell you to load and shoot?
6) Mfrs. do find better powders and recipes to make their products better or more efficient. But at what cost and for who? Them or us? In 2016 Allient did tell me they quit telling people to load Red Dot in .38 Special because it is too fluffy and doesn't meter very good. They gave me the info. because I told them I weigh every load.
* ) I, for one, would not want to ruin the $1,000+ gun just to save a few pennies on components. I do review how I used to load. BUT, I rarely shoot max. I see little benefit in it.