Temperature stability of Power Pistol?

[rutilate]

There is quite a bit of testing that shows that said that bullet velocity would increase by between 1.0 and 1.7 fps for every 1 degree temperature increase.
http://www.americanhunter.org/blog.php?id=21542&cat=56
http://www.longrangehunting.com/articles/ballistics-temperature-velocity-1.php
http://www.exteriorballistics.com/ebexplained/4th/56.cfm
and more.

I just re-chrono’d some Power Pistol loads at 72 degrees that I’d originally measured at 41 degrees and found that the variability was only 0.29 fps/1 degree temperature increase. Thus, original velocity of 1133 fps at 41 degrees increased to 1142 at 72 degrees (1142-1133 fps)/(72-41 degrees)=0.29 fps/degree. The loads fired at the warmer temps were from the same batch as the original loads fired at cooler temps.

Does that mean that:

1. Pistol bullet velocities are not as sensitive to temperature as rifle?
2. Pistol powders are more temperature stable than rifle powders?
3. Power Pistol is a temperature-stable powder?

 

[kayak1]

Off the top of my head my thought would be that the pistol pressures are only ~1/3 of the rifle pressures thus you may need to include the pressures into the equation.

 

[Supermoto]

it means every powder is different, some are reverse temp sensitive

 

[73BLow]

How precise do your pistol reloads need to be in order to know that it's the temperature affecting your velocities?

If it were 41 degrees out tomorrow and you tested the same batch and you had a 9fps variance compared to the last 41 degee day, it wouldn't sound like a significant number to me unless every round you shoot clocks in within a few fps of each other. Can you experienced pistol reloaders hold that kind of tolerance on your shot to shot fps?

I am asking all this because I am brand new to reloading and have a chrono delivering in a couple days so I can test my first loads I have worked up. From the chrono videos I've watched so far, I've seen some significant variances in shot to shot velocities on factory defense pistol ammo. I suppose it depends on how good the chrono is too.

 

[Supermoto]

it really depends on the shooting you are doing. For me with uspsa, I need to make power factor of 165. If i go below that, I get scored at a lower %, so knowing what your powder is going to do based on the weather is helpful.

 

[73BLow]

it really depends on the shooting you are doing. For me with uspsa, I need to make power factor of 165. If i go below that, I get scored at a lower %, so knowing what your powder is going to do based on the weather is helpful.

I understand that. What I am wondering is how accurate can you (or anyone with a fair amount of experience) load a pistol round. Can you keep your velocity for every round within 5, 10, 15fps of each other?

If you can't load each round to be within 10fps of each other, I was thinking in the OP's example, you wouldn't know if the change in velocity was due to the effect of the temperature on the powder or due to slight deviations in the amount of powder dropped even though they're from the same batch.