I'm about to experience a 1000 foot elevation change upwards and a 40 degree temp drop from where my load was developed. I'm shooting a 223 with a .3gr wide node, so I don't have allot of wiggle room. I've talked to a knowledgeable person about this earlier but would like to hear what others think. Would keeping my bullets warm in a cooler for the first string or two help, or would that not help because it's the actual ambient temp that causes changes to the load. I do have a tuner on this gun but have never had to use and it's not been cold enough to test it before today.
Environmental changes and loads
- Thread starter jsthntn247
- Start date
I experienced pressure surges with H380 in my 22 250 when hunting ghogs in 90 degree+ weather. This load showed no signs of pressure at the range. The only thing I can think of is that the cartridges somehow became over heated in the field. I've only experienced this with ball powder, specifically H380. When I switched to Varget I had no such problems.
Powder? Some are more temp sensitive than others.
Both the temp of the cartridge and the temp of the chamber can make a difference. Chamber temp matters more if you let them "cook" (sit in the chamber for > 10 seconds) before firing. My buddies and I try and avoid cooking rounds in the chamber, so we don't close the bolt until the target ia back up and we are ready to shoot.
But if your habit is to close the bolt and let them cook until the target comes back up and the condition is right, then keep it the same. With a ball powder or a RL series powder (or any double base), I would take care to keep the rounds warm. With Varget, I wouldn't bother. I might let the box warm in the sun in winter and keep it shaded in summer.
Both the temp of the cartridge and the temp of the chamber can make a difference. Chamber temp matters more if you let them "cook" (sit in the chamber for > 10 seconds) before firing. My buddies and I try and avoid cooking rounds in the chamber, so we don't close the bolt until the target ia back up and we are ready to shoot.
But if your habit is to close the bolt and let them cook until the target comes back up and the condition is right, then keep it the same. With a ball powder or a RL series powder (or any double base), I would take care to keep the rounds warm. With Varget, I wouldn't bother. I might let the box warm in the sun in winter and keep it shaded in summer.
Keith Glasscock
Gold $$ Contributor
I'm a round cooker. I almost never fire a round that hasn't been in the chamber 5 to 10 seconds. If I go past 20-30, I remove the round and swap it for a cold one.
The difficulty comes when starting a string. The POI will change with temp sensitive powder because the barrel warms up slowly over the first 10 rounds. H4350 and Varget are much less prone to this than RE-15 for example.
The difficulty comes when starting a string. The POI will change with temp sensitive powder because the barrel warms up slowly over the first 10 rounds. H4350 and Varget are much less prone to this than RE-15 for example.
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