I just don't let a round cook for more than a few seconds, typically. Powder being a cellulose product, it's a decent insulator, so doesn't change super fast. I think that's why I don't see tune change so much, if any, due to bbl temp but rather, ambient, as the powder has time to change.I believe you are right, Although each round was progressively heating up in that case of the last group I posted.
Each shot showed to be climbing.
That 3rd highest shot SHOULD have been a slight increase in velocity due to temp
I mainly wanted to just see how wacky things would go if I left a round in the chamber with the bolt closed
(As if waiting for a shot that might happen any second so you dont chance even having the bolt lifted because that split second is too long)
Any other time I would not leave a Round cooking in the hot chamber that amount of time.
I liked the test results at that short range but need to repeat the same again at longer range
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So....... more testing with a Tuner will come this season
I wonder if it will tune out vertical from leaving a round in the chamber?
That would be cool!
You and others have touched on station pressure as well as temps so I'll add what I've been able to observe a bit.
First thing is, smokeless powder turning from a solid into a gas is a chemical reaction and all chemical reactions are temp dependent.
The other thing is that air pressure very much appears to have an offsetting affect on tune as opposed to temp. Which very well may explain why identical temp changes from day to day...one day the tune clearly goes away but the next, it seems to hold tune very well. Pressure and temp are related but they don't always change linearly and the same from day to day, for example. I've seen this both ways many times but the first was in tornadic conditions where temp was stable but tune left, badly and I struggled to find it moving the tuner the way I "thought" based on temp and group shapes. Something to keep in mind is all. But the key to keeping a gun in tune is generally group shape. I can't emphasize that enough. Shooting in a tornado or a hurricane, where the air pressure just plummets, does seem to change the direction you would need to go, be it tuner, seating or powder, though. I've tested this three times and it seemed to hold true. Tough conditions to replicate, fortunately.