Hunting load development in the heat

[Tac-O]

I typically go shoot at the range once a week for enjoyment and it usually involves some sort of testing because I'm only a year in to loading and I'm enjoying the learning aspect.

One thing I haven't really paid much attention to is temperature stability curves. This is for a few reasons: I'm usually just shooting at 100yds and typically don't have a set load that I regularly shoot for groups, my current acceptable range for shooting at game is short enough that ES/SD doesn't really matter, and I have been using temp stable powders.

I would like to start thinking about my load development with regard to the temperatures I may hunt in, but I don't want to limit load development to times of the year that the ambient temp is what it would be while hunting. I know many people don't do it when it's warmer than 80F outside, but it's been 90-100 here for at least the last month and it's not letting up very soon.

I have a couple of ideas to mitigate any outside temperature influence and am wondering what other people do.

1. Use a small cooler with ice packs to store my rounds in at the range with my multimeter's temperature probe inside the cooler. (I currently keep them in my office at work until I go to the range and then keep them somewhat insulated in my bag until I'm ready to shoot each cartridge)
2. Use ice water and a towel to keep my barrel and chamber as cool as possible between shots (I currently do this every other shot so I can get 20-25 rounds done in the heat a little faster)
3. Break the trigger within 15-20 seconds of loading the round into the chamber.

In doing these things, I would think that my cartridge temperature may be around 40-45F when I break the trigger. This would be a much better middle ground temperature to develop loads in and not have to worry about extrapolating temperature stability curves.

What are your thoughts on my plan? Can you poke any holes in it? What are some tricks that you use to keep it simple and effective?

 

[BoomFlop]

You will never be able to replicate the conditions you will be using the load in with your plan. Enjoy your time at the range, test things and continue to learn.

When temperature drops to your hunting conditions, continue to test and tweak your load as needed.

Nothing will ever replace the actual conditions.

Good luck
Steve

 

[Tac-O]

You will never be able to replicate the conditions you will be using the load in with your plan. Enjoy your time at the range, test things and continue to learn.

When temperature drops to your hunting conditions, continue to test and tweak your load as needed.

Nothing will ever replace the actual conditions.

Good luck
Steve

Yes I know it won't replicate conditions, but it would at least mitigate the huge swing from 90F to 30F. And of course I would be checking the load as outdoor temps drop and hopefully wouldn't have to make any huge changes to it. That would be the intent and purpose of what I'd laid out.

 

[Dirtrax]

Ambient temp affects bullet flight ((drop) characteristics while powder temp affects combustion to varying degrees unique to the powder. A temp stable powder such as H-1000 changes very little throughout large swings. If I recall correctly it's on the order of .25 fps/degree(f).
This of course varies depending on lot# and other factors but I've experienced good consistency.
So I shoot in temps ranging from 10f to 100f. Simple math indicates a swing of 22.5 fps throughout the range. SD is 11.25 fps. My experience shows this to be the case. That being said I don't allow my loaded rounds to reach these extremes in practice. I place the ammo in an insulated pouch I made and place it out of direct sun or in a pocket when cold. Chronograph testing has eliminated temp as much of a concern which has been verified by field testing. I generally single feed but I have no concerns should I need to keep rounds in battery.

 

[BoomFlop]

Here you go:

 

[Mikecr]

The cooler idea is terrible. You'll be coating every round with condensation and never practical in the field.
Instead, keep your rounds loose in your front pants pocket, all year round. Load develop like this. Pull them from your pocket one at a time to shoot.
Thats powder problem solved, but the barrel still needs cold bore development for each hunting temp range. Cold mid high

 

[ButterBean]

The cooler idea is terrible. You'll be coating every round with condensation and never practical in the field.
Instead, keep your rounds loose in your front pants pocket, all year round. Load develop like this. Pull them from your pocket one at a time to shoot.
Thats powder problem solved, but the barrel still needs cold bore development for each hunting temp range. Cold mid high

That's good in theory but totally unacceptable in the field

 

[ButterBean]

You will never be able to replicate the conditions you will be using the load in with your plan. Enjoy your time at the range, test things and continue to learn.

When temperature drops to your hunting conditions, continue to test and tweak your load as needed.

Nothing will ever replace the actual conditions.

Good luck
Steve

^^^^^^^^^^^^^^^
What BoomFlop said, Way to many variables other than the ammo, Don't worry yourself to much with this as it's been proven time and again not to be near as critical as you would think, I'm not saying it's to be ignored but in most cases can be accounted with very slight hold adjustments and muscle memory

 

[nt7332]

I used to do something similar but it was strictly for seeing variations in different powders. I would keep 5 rounds in double zip lock bags on ice with the coors. I would have another 5 in a zip lock and I would lay them on the defroster in the truck. Drink a coors and by the time I was done bullets was nice and heated up. Shoot those hot rounds over chrono, have a coors and then shoot cold round over a chrono. Results was shocking with some powders in velocity numbers. Occasionally I would shoot groups with hot and cold rounds just for fun. All in the name of science.

 

[Tac-O]

Thanks for all the insight! I guess I won't go through the trouble of messing with the cooler.

 

[BoomFlop]

Continue to have fun, continue to learn. Have a summer load and a winter load. Tweak load and then you will know for sure what it does under different conditions.

Steve

 

[26Reload]

But his cold Coors sounds like a good idea.....
I figure my hunting weather is usually mid 60s to mid 70s for Muley...freezing to 50s whitetail....flip coins to see which rifle makes the joint...dont rightly play temp swings.....if I am worried..i get closer.....

 

[Dirtrax]

I don't adjust for variation in case weight assuming it's within a self determined range. I sort weights and know what to expect. I shoot in variable temps and know what to expect given a specific weight/charge. The ballistic app I use can account for the variances and they are confirmed. It seems unreasonable that one would shoot ammo with discrepancies so broad in both capacity and temp sensitivity that It's not readily managed. All I am saying is don't make this more complicated than it needs to be. In the field most will never be able to discern the difference. How many rounds does anybody expect to fire hunting? It is no burden whatsoever to assemble 5-10 identical rounds leaving one to worry about the very real concern of firing your rifle in all the conceivable positions you may encounter. Even then limit yourself to the 2-3 that you can confidently use and stay within your capabilities.
Ryan...nobody can be a master of all things, choose your priorities and master those first. You can always add to the list as your skill allows. Occasionally the internet leads one to unrealistic expectations.
None of my comments are directed negatively at anyone offering advice in this or any thread. I've just seen too many consistently successful hunts by folks that internet wisdom would indicate couldn't possibly get the job done.

 

[3800fps]

If you develop an acceptable load (accuracy and speed to your liking) in warm/hot temps with temp stable powders , when cooler hunting time arrives I'll guarantee you that the outcome of your hunt will not depend on any small shift in impact caused by 20-50 degrees in ambient temperature...perhaps at over extended ranges 400+....but not at ranges you indicated...