Keep Your Ammo Cool in Insulated Multi-Purpose Carry Pack
It’s vitally important to keep your ammo at “normal” temps during the hot summer months. Even if you use “temp-insensitive” powders, studies suggest that pressures can still rise dramatically when the entire cartridge gets hot, possibly because of primer heating. It’s smart to keep your loaded ammo in an insulated storage unit, possibly with a Blue Ice Cool Pak if you expect it to get quite hot. Don’t leave your ammo in the car or truck — temps can exceed 140° in a vehicle parked in the sun.
Insulated Case Does Double-Duty
Standard plastic coolers work fine, but if you don’t want to borrow the family’s food carriers, consider this Norchill insulated Cooler Bag. When not used to keep your ammo cool, the 7″ wide x 12″ high x 14″ long small Norchill Bag doubles as a gear carrier. Norchill bags feature dual-temp insulation and a waterproof inner liner. With side-zip compartments, Norchill Cooler Bags are more versatile than typical plastic coolers. These Norchill cooler bags are soft, collapsible and can be rolled up to fit into your carry on luggage. When not in use for ammo, they can be used to as a suitcase, or carry bag for cameras, optics, and electronic gear.
Norchill Bags come in three sizes and a variety of colors. Price starts at $39.99 for the small bag (12-can capacity) is $39.99. The 10″x12″x18″ medium bag has double the capacity (24 cans) and costs $49.99. There is also a jumbo 48-can capacity bag, 13″x13″x21″. But this is probably more capacity than you’d ever need.
For example, barrel temperature was a key factor: “Both barrel temperature and powder temperature are important variables, and they are not the same variable. If you fail to take barrel temperature into account while doing pressure testing, your test results will be very significantly affected. The effect of barrel temperature is around 204 PSI per F° for the Varget load. If you’re not controlling barrel temperature, you about as well might not bother controlling powder temperature, either. In the cases investigated, barrel temperature is a much stronger variable than powder temperature.” |
To learn more about how ambient temperature (and primer choice) affect pressures (and hence velocities) you should read the article Similar Posts:
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- Don’t Roast Your Ammo — Watch Temps in Hot Summer Months
- Beat the Heat — Keep Ammo Cool During Hot Summer Days
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Tags: ammo, Bosch, Cooler, Heat, Ice Pack, Insulation, Temperature
This was great testing. But it seemed just the beginning. I wish there was a follow-up(part-II) to look at the mysteries identified..
I believe the 4350 comparisons because it aligns with my personal testing, that led to use of I over H.
This was with a 26wssm.
Maybe I missed it, but I didn’t see how they surmised that barrel temps messed with powder temps -in their testing.. I found that I would have to leave a 6XC sized case in a warm chamber for ~1min before velocities change. I’m sure they noticed that as well.
I’ve done a fair bit of cold bore load development, and it’s alot of work for sure.
Some things I’ve learned for hunting related to temps:
-Be fully ready to shoot before ever loading. Never waste time once a round is chambered.
-Load single shot.
-For a hunting load keep ammo in pants pocket both at the range, and in the field, regardless of temps.
-Choose cut rifled barrels for hunting guns.
-Use purpose built loads below 40deg(due to bore constriction, and special ignition needs).
A side note about the cooler idea; Do not reduce ammo temps below dewpoint, else you’ll get water in the chamber with loading(dangerous).
If shooting in warm weather, ammo temps will vary less by warming it, rather than cooling it. Hence the pants pocket warming. Your body is an excellent temp regulator.
Have to agree with Mikecr, this article was just getting started. After a lot of testing and correlating Quickload forecasts against reality, and then plugging the Lex Talus FFS program for the exteriors, the importance of temperature has truly been driven home here, particularly for Australian hunting conditions, where temperatures can vary enormously.
One thing keeps popping up, that I haven’t seen discussed yet, is the issue of temperature on nodal point identification. If a minimum load is developed on an assumed minimum temperature, and a maximum load developed on an assumed maximum temperature, the load band recommendation suddenly becomes very narrow, often within 1.5 grains for cartridges using more than 50 grains of powder.
I have found that an accuracy nodal point occurs within this band, with the greatest degree of flexibility and tolerance for changes in temperature. Even though point of impact changes still occur, hunting accuracy tolerances at least are maintained.
Whilst I cannot “prove” this theory to be correct, I have yet to prove it wrong.
Would love to receive more articles on this subject.