Short range group shooting, powders changing during the day?

[Mulligan]

Background,
I am a fairly new shortrange BR (group) shooter. I shoot in Western Colorado where you can have 50* swings in temperature and extremely low (single digit) relative humidity. I expect parts of UT, WY, ID, MT, NM, AZ, NV, Eastern OR, and Eastern WA to have similar temp and RH swings???? But not sure.

I started out shooting LT-31, yes a 50/50 blend of LT-30 and LT-32 as that is the "go-to" powder here locally. I quickly realized that the mixed powder thing gets in my head and fouls me up so I gave it up. Don't get me wrong, it shoots, just a personal thing with me.
I tested LT-30 and LT-32 alone and LT-32 shot the best for me..... until it didn't. Please don't get me wrong, LT-32 works pretty good.

I then tried N-133, and it shoots fairly reliably here when the summer SW Monsoon is visiting and we have higher RH (in the normal to low range for our eastern brothers 40-50%). When RH gets in the 30's or lower, things change like cayuse with a belly full of oats, plumb crazy.

A few days ago, I weighed out 26.0 grains of 133 and set it outside to see how fast the powder dried as I expect that is the real issue. Sure enough, in 10 minutes that 26.0 gr charge weighed 25.9gr. 30 minutes later, it weighed 25.75gr. All these weights are from an FX120i scale. I trust them, if you don't, I'm good with that.
I set out a pan of 133 to normalize it with the current conditions and plan to shoot it soon.

So here's the question, what's the best way to deal with powders drying out during the day?

CW

 

[LHSmith]

Preload at home in controlled environment and adjust tune at the range with a tuner. Final seat bullets at the range.

 

[RegionRat]

All the BR group shooters I know compensate the tuning for the local temp, pressure, and humidity as they go.

If the start of the day is a big change from their last session, they compensate. If the day changes as they go, they compensate.

Every BR shooter I know that takes it seriously, becomes a bit of a weather expert in order to track all the things that affect their tune at a match.

Some just roll up their sleeves and get to work, while others start with a careful study of their weather gages for actual local conditions and since they have been at it a long time they have a pretty good idea of what direction to tune right out of the gate. Some have a barrel tuner setting for the local pressure of the range they dial on before they even start.

I don't shoot BR so in time those folks will chime in.

In my world (preloaded and stored), if you had to make reliable ammo, it had to be loaded under controlled conditions and either sealed or stored properly to insure the DOPE would be reliable from batch to batch no matter where it went to be shot.

I see weather gages in your future....