What temp is too hot for load development

This load was fine at 50 degrees F. It was not in the upper 70s. I am just going to back off .3 to .5 grains and see where I am. Per ladder testing and OCW testing I may be just outside my node with these weights, but too much pressure even in a node is not good.
Nodes don't exist, dropping powder charge can decrease dispersion, but all the testing in tenths of grains of increments is a waste of time and components if you're trying to see if the rifle like the combination or not. If you want to expedite your loading process, just shoot bigger sample sizes, that's what actually matters. 10 usually does the trick, if it's around 1 MOA or less, it's a good load. If 1.5 or more, try a different powder or bullet. The combo either shoots or it doesn't, it's really that simple.

I'll give you an example of a very similar situation, this winter I did temp testing on fireformed brass in my 6.5 PRC using N565 shooting 143's. At 29° my initial charge (that was safe last summer in new brass) was at pressure, which I expected. I dropped the charge 1.5gr to be sure it would be safe in warm weather, got velocity, and trued up my solver. This weekend I shot out to 920 yards in 80° verifying that charge was still safe, and the temp factor was dialed in. No pressure, no issues, 6/6 impacts at 830 and 920.
 
Nodes don't exist, dropping powder charge can decrease dispersion, but all the testing in tenths of grains of increments is a waste of time and components if you're trying to see if the rifle like the combination or not. If you want to expedite your loading process, just shoot bigger sample sizes, that's what actually matters. 10 usually does the trick, if it's around 1 MOA or less, it's a good load. If 1.5 or more, try a different powder or bullet. The combo either shoots or it doesn't, it's really that simple.

I'll give you an example of a very similar situation, this winter I did temp testing on fireformed brass in my 6.5 PRC using N565 shooting 143's. At 29° my initial charge (that was safe last summer in new brass) was at pressure, which I expected. I dropped the charge 1.5gr to be sure it would be safe in warm weather, got velocity, and trued up my solver. This weekend I shot out to 920 yards in 80° verifying that charge was still safe, and the temp factor was dialed in. No pressure, no issues, 6/6 impacts at 830 and 920.
I appreciate your response, but we are going to respectfully disagree on whether there are nodes with regard to loads. I do agree with the statement that the combo either shoots or it does not. I can’t for the life of me understand how using a 10 shot system saves time and components. Glad your system works for you. Best to you. Thanks again for your response.
 
I do agree with the statement that the combo either shoots or it does not. I can’t for the life of me understand how using a 10 shot system saves time and components.
If you agree on that, then hear me out; you only shoot 13-15 shots max and you're either done, or loading a new test. As opposed to shooting 30 or 40+ rounds testing powder charges and seating depths with samples that have up to 70% variability built into them, getting results with very little validity.

If you like testing and burning up components with trigger time, by all means continue mission. But if you're intrigued by this at all, try it sometime. Pick a seating depth, shoot a short pressure ladder or grab a charge you know is safe from experience, and load and shoot a 10 shot group. Then do your traditional load development and shoot a 10 shot group of your final load for comparison. Factor in the 20-30% variability and I'd be willing to bet they statistically produce the same result.
 
Okay, anyone that has an elk and a beautiful woman in his avatar gets my respect and attention (two of my favorite things). You check that box. Lets say I either shoot “a short pressure ladder” or I shoot one at 600 yards. In my world that 600 yard test is going to give me a 1 grain node generally where the most reliable (maybe not the most benchrest accurate) load will be. I shoot 2 shots per powder weight in a ladder. I will generally load every .5 grains for lets say a .284 caliber. That is maybe 12 - 14 shots. I will then normally pick 4 seating depths and test with three shot groups assuming the powder proved up with positive results with the ladder test. At times a bullet and powder just will not work. My seating depth test is another 12 shots.
Then I am “normally” have it narrowed down to one grain where that gun should shoot. Lets say 68.5 to 69.5 grains. I load three shots at 68.7,68.9, 69.1, 69.3. Usually one of those will be noticeably better than the others. At that point, I am in at under 50 rounds.

My question to you is after I do my short ladder test for powder testing, what do you mean my “traditional load development”. Please give me more detail as to your process.
 
Okay, anyone that has an elk and a beautiful woman in his avatar gets my respect and attention (two of my favorite things). You check that box.
Haha, thank you! That was her first elk (she drew a good tag), and she earned it! Open sight black powder muzzleloader hunt of a lifetime.

Lets say I either shoot “a short pressure ladder” or I shoot one at 600 yards. In my world that 600 yard test is going to give me a 1 grain node generally where the most reliable (maybe not the most benchrest accurate) load will be. I shoot 2 shots per powder weight in a ladder. I will generally load every .5 grains for lets say a .284 caliber. That is maybe 12 - 14 shots. I will then normally pick 4 seating depths and test with three shot groups assuming the powder proved up with positive results with the ladder test. At times a bullet and powder just will not work. My seating depth test is another 12 shots.
Then I am “normally” have it narrowed down to one grain where that gun should shoot. Lets say 68.5 to 69.5 grains. I load three shots at 68.7,68.9, 69.1, 69.3. Usually one of those will be noticeably better than the others. At that point, I am in at under 50 rounds.
Dispersion is linear so I don't do anything past 100 yards for load testing. The problem with testing all those powder charge iterations is the variability built into the sample size. So I absolutely agree that if you test 68.7, 68.9, 69.1, 69.3, it will probably produce a group that's noticeably better than the others. The problem is, it's not repeatable. If you were to keep pumping rounds into those groups at those powder charges, the tightest group would open up and the largest group would fill in, and the end result of the 2 groups would be the same, +/- X% depending on sample size. SOMETIMES the higher powder charges produce more dispersion, that is known and stated by ballisticians. But the same variability goes for seating depth, I started a thread years back called "Does seating depth even matter?", and after 8 or so pages there wasn't one single piece of valid evidence that someone "tuned" the seating depth to get less dispersion out of a load.

My question to you is after I do my short ladder test for powder testing, what do you mean my “traditional load development”.
I mean do it how you do it, how you explained in your reply. 600 yards, 68.7, 68.9, seating depth test, etc. The point is to compare the hodge podge easy method group to your fully developed group at the end with somewhat valid sample sizes and see if you actually made an improvement. After doing this multiple times in a variety of calibers, I have not been able to, nor have I seen valid proof of anyone else doing so either without switching a component.

Please give me more detail as to your process.
The Painless Load Dev/Hornady method. I load .040-.050" off the lands (most of my chambers are spec'd for a certain bullet weight to be that far off with the boat tail edge seated to the neck shoulder junction), or mag length and I shoot a pressure ladder 1 shot each in .5gr increments starting 1-2gr below avg published book max up to 1gr above and look for pressure. I'll drop at least 1gr from signs like ejector marks, and 2gr from bolt lift to stay out of trouble if I get moisture on a case while hunting or something. Then I shoot a 10 shot group, 2 strings of 5 shots cooling in between. My goal is for it to be under 1". If it does that, I'm done. If it's over 1.2", I swap bullet or powder, and repeat. Typically I will switch powder first, I've seen dispersion cut in half by different powders. But sometimes a barrel doesn't like a bullet and I'd rather have a good temp stable powder than a certain bullet. If I go through 2 reputable powders and 2-3 bullets without getting an acceptable result, I chalk that one up as a loss and will replace the barrel.

To add more to the intent of the thread, I like to test in warm weather. If it's super hot I may do another quick pressure ladder later and see if it's safe to bump the charge up a bit in more moderate weather. Also I'm sure you know but it's worth noting that if you go full tilt on new brass and are loaded right up to the edge of pressure, it will likely show up after brass is formed. Expect to drop the charge after 1st firing, as I explained in my previous comment.

Here's the result of that exact process. I tested H1000 and N565 using that process. The H1000 group opened up a bit toward the end (could have been mirage, could have been me), but the N565 group had plenty good velocity and grouped like this.
Screenshot_20240803_161610.jpg
 
I did mine in 108 degrees lol. Which worked out fine cause I can make sure I don’t have pressure issues when I shoot in the summer.
 
I will keep my ammo in a cooler (at the Range) so it stays pretty close to the temps I hunt in. Of course we can't control the weather so I try to keep it close to actual as possible. I have had FTF on 308 suppressed when the temps dropped below 30, the load was perfect at 40-80? Low pressure was my guess. have not had to many issue's with a bolt gun.
 
Haha, thank you! That was her first elk (she drew a good tag), and she earned it! Open sight black powder muzzleloader hunt of a lifetime.


Dispersion is linear so I don't do anything past 100 yards for load testing. The problem with testing all those powder charge iterations is the variability built into the sample size. So I absolutely agree that if you test 68.7, 68.9, 69.1, 69.3, it will probably produce a group that's noticeably better than the others. The problem is, it's not repeatable. If you were to keep pumping rounds into those groups at those powder charges, the tightest group would open up and the largest group would fill in, and the end result of the 2 groups would be the same, +/- X% depending on sample size. SOMETIMES the higher powder charges produce more dispersion, that is known and stated by ballisticians. But the same variability goes for seating depth, I started a thread years back called "Does seating depth even matter?", and after 8 or so pages there wasn't one single piece of valid evidence that someone "tuned" the seating depth to get less dispersion out of a load.


I mean do it how you do it, how you explained in your reply. 600 yards, 68.7, 68.9, seating depth test, etc. The point is to compare the hodge podge easy method group to your fully developed group at the end with somewhat valid sample sizes and see if you actually made an improvement. After doing this multiple times in a variety of calibers, I have not been able to, nor have I seen valid proof of anyone else doing so either without switching a component.


The Painless Load Dev/Hornady method. I load .040-.050" off the lands (most of my chambers are spec'd for a certain bullet weight to be that far off with the boat tail edge seated to the neck shoulder junction), or mag length and I shoot a pressure ladder 1 shot each in .5gr increments starting 1-2gr below avg published book max up to 1gr above and look for pressure. I'll drop at least 1gr from signs like ejector marks, and 2gr from bolt lift to stay out of trouble if I get moisture on a case while hunting or something. Then I shoot a 10 shot group, 2 strings of 5 shots cooling in between. My goal is for it to be under 1". If it does that, I'm done. If it's over 1.2", I swap bullet or powder, and repeat. Typically I will switch powder first, I've seen dispersion cut in half by different powders. But sometimes a barrel doesn't like a bullet and I'd rather have a good temp stable powder than a certain bullet. If I go through 2 reputable powders and 2-3 bullets without getting an acceptable result, I chalk that one up as a loss and will replace the barrel.

To add more to the intent of the thread, I like to test in warm weather. If it's super hot I may do another quick pressure ladder later and see if it's safe to bump the charge up a bit in more moderate weather. Also I'm sure you know but it's worth noting that if you go full tilt on new brass and are loaded right up to the edge of pressure, it will likely show up after brass is formed. Expect to drop the charge after 1st firing, as I explained in my previous comment.

Here's the result of that exact process. I tested H1000 and N565 using that process. The H1000 group opened up a bit toward the end (could have been mirage, could have been me), but the N565 group had plenty good velocity and grouped like this.
View attachment 891960
Harvey, going to give you method a try. What do you do for a living? Statistician? LOL
 
Harvey, going to give you method a try. What do you do for a living? Statistician? LOL
Right on! No, I'm actually an ag mechanical tech now, spent a lot of time in fab/machine shops before this. I'm just a research nerd that likes to fully understand things. When learning to reload I got consumed by the traditional dogma, but I didn't lie to myself and observed it's shortcomings. Then I ended up here, where Form explained and produced some Gov't documents about establishing the cone of fire, and how none of the little tweaks people make are actually changing the precision of a load, and it all made sense. Then Hornady put all this info out on their podcast, and I listened to it enough to memorize the variability of sample sizes to try and explain and help others not waste money.
 
My loads in general need to be safe on a 100F day.
We'll get easily 30 of those in a year. And one day with a morning at 15F. I try to validate my loads at a minimum of 90°. We were making dope tables last Saturday at 93. With a flea market canopy top and a little wind it was pretty comfortable.

I got in big trouble developing loads at 50° F.
 

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It gets hot in NC but not as hot as some of the other guys. Like its already been said, the top must haves for hot weather load development are:
- Barrel/chamber fan
- Battery fan to blow on the gun and shooter
- Get started early

But once you find a load that shoots good in the heat, it usually shoots well when its colder and you know you will be fine pressure wise.

Cloudy days are a blessing so if I can shoot one of those days, even better. Keeping the gun and shooter cool is the challenge. Bring plenty of water, take breaks often, and plan for it to take twice as long as when its cold.

But, if your at a public range you will often times have the place to yourself since most people wont shoot when its hot.
 
Air temp doesn’t really matter, it’s the temp of your rifle and ammo. Put your ammo and rifle out in the sun on 70 degree day and check it with an infrared thermometer after an hour. Put them in the shade for an hour on a 100 degree day and compare the numbers.
 
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