loading for the temperature
- Thread starter jmason
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Depending on the rifle and powder I do it all of the time BUT the chrono is the way you can tell what is really going on. There is no free lunch so to speak. Never have I had a load that shot at a higher velocity on a colder day.
A possible issue is the 1st shot thru a clean tube--higher pressure possibly and with factory tubes most likely a different POI. Just something to keep in mind..
A possible issue is the 1st shot thru a clean tube--higher pressure possibly and with factory tubes most likely a different POI. Just something to keep in mind..
royinidaho
Well-Known Member
RL-22 in 270 Win. - 130 FPS velocity reduction from 70* summer temp to teens in winter.
With powders such as IMR 7828ssc I load to max in less than 70* temps and don't worry about it except in my long range guns where I am a bit more particular.
When I chrono a given load @ lower temperatures it is always lower than in warmer temps. If it is sufficiently low I enter the lower velocity into the drop chart program and make a new drop chart. I'm not one to have a cold weather load and a warm weather load. I'd invariably get'em mixed up sooner or later.
With powders such as IMR 7828ssc I load to max in less than 70* temps and don't worry about it except in my long range guns where I am a bit more particular.
When I chrono a given load @ lower temperatures it is always lower than in warmer temps. If it is sufficiently low I enter the lower velocity into the drop chart program and make a new drop chart. I'm not one to have a cold weather load and a warm weather load. I'd invariably get'em mixed up sooner or later.
Ditto.
Another thought... Reduced velocity at lower temperatures can change more than just trajectory. Barrel harmonics can affect group size and POI. jmason's idea of using a charge that's at the high end of the node sounds like a reasonable approach, but the only way to tell for sure is to test at the anticipated lower temperatures.
Another thought... Reduced velocity at lower temperatures can change more than just trajectory. Barrel harmonics can affect group size and POI. jmason's idea of using a charge that's at the high end of the node sounds like a reasonable approach, but the only way to tell for sure is to test at the anticipated lower temperatures.
Thanks guys. I will test it in colder weather for sure. I was just looking for validation of my thought.
AJ Peacock
Well-Known Member
royinidaho
Well-Known Member
I figure that if group size doesn't change with large drops in temperature with 200 yd point of impact being the only change, a tweak up in zero setting being necessary, then the drop chart change is considered based on a downrange point of impact check along with the chrono check.
There was a thread a while ago, regarding "how wide is your node". That consideration is very important. Node width seems begs for a bit more consideration of the OCW method of load development along with the Ladder method.
There was a thread a while ago, regarding "how wide is your node". That consideration is very important. Node width seems begs for a bit more consideration of the OCW method of load development along with the Ladder method.
The way I have been doing load development is to shoot a ladder. If I find what I perceive to be a node I then add and subtract a few grains on the high and low side of the node and shoot confirmations. For example if I thought I had a node at 55.4-55.7 I'll load 55.2, 55.4, 55.6, and 55.8 (or wider) and look for similar velocities and POI shift to find the edges of the node. I then select what is the center of it. I'm going to loose 30+ degrees before rifle season so I figured if I went to the high side of the node (guessing) all would remain well when it gets colder.
Either way I'll learn the hard way later this fall!
By the way I authored "How wide are your nodes"
Either way I'll learn the hard way later this fall!
By the way I authored "How wide are your nodes"
