Powder Burn Rate & Ballistics for Precision Rifle

[Barn Side]

I love using Delta V FFS but struggle with obtaining powder burn rates. I usually put five rounds in a snap lock bag on ice to obtain the cold velocity and five rounds in a snap lock bag & warm water to obtain the hot velocity. I obtain the temperature using a waterproof thermometer measuring alongside the rounds. Just recently I didn't let the temperature stabilize long enough before chronographing both the hot & cold velocities as I was being rushed due to range closure times with the whole thing being a waste of time. And the process is a pain organising an esky with ice and thermos with hot water, thermometer etc. My other gripe is that I'm think my rounds are cooling or heating a bit between the time I remove them from the esky or thermos and feed them in to shoot. Just wondering is there a more accurate way of measuring powder burn rates for factory ammunition?
Is there somewhere I can just find the powder burn rates for factory ammunition that have been measured under more controlled or accurate circumstances?

 

[ShtrRdy]

I'll try to answer. I think your approach is basically a good way to do it. I would suggest using one of those laser thermometer instruments to measure the side of the case just before putting the cartridge in the chamber. Get set up so that when you chamber the cartridge right away. Don't bother pointing the sights at a target. But make sure its pointed at a backstop.