Reloading in hot weather

[rogerthat]

I know there are some very good reloaders that frequent this site. I am not one of them. Just curious on everyone’s thoughts on reloading and developing loads in hot weather. Is this a waste of time? Will groups shot in cooler weather translate to good groups in hot weather and vice versa? I am using varget which my understanding is not very temperature sensitive. Any thoughts or best practices to follow when trying to develop and verify loads and the weather is hot?

 

[cgasner1]

Stable powder it doesn’t matter much other than it’s super time consuming wait for the barrel to cool between groups compared to when it’s 30 out

 

[std7mag]

With Varget it's not bad.
It's probably better to do load development when it's hot out, than when it's cold.
Do load development with powders like H223, and you'll over pressure when it's hot.

 

[brockel]

More of an issues with barrel heating up in hot weather effecting load accuracy over the reloading itself as long as I’m using a temp stabile powder. That’s why I’ll do my shooting right at dawn in the summer months usually

 

[jryoung]

I learned with RL-22 that I like to do load testing when it is hot. In CA deer season starts when it's 100 out, then, if I have tags it can be 0 in MT, WY, ID etc. Most everything I load now is with temp stable powders. Brockel is right about warm barrels, I try to bring as many rifles as I can to the range to rotate through.

 

[Wind Gypsy]

Just know that velocities might dip a little when it's cold, even with varget. I wouldn't worry about it much.

Hot barrels bother me more in the form of mirage than anything else. I don't worry about them getting hot for accuracy purposes.

 

[EastTNHunter]

Heat sinks help to cool the barrel. I like a .25 aluminum rod. Can also keep ammo in a cooler. I’ve also used air in a can or a compressor and blower nozzle to cool off a hot barrel on a warm day.

Southern humidity makes it hard to cool a barrel when it warms up

 

[Sheltowee]

Heat sinks help to cool the barrel. I like a .25 aluminum rod. Can also keep ammo in a cooler. I’ve also used air in a can or a compressor and blower nozzle to cool off a hot barrel on a warm day.

Southern humidity makes it hard to cool a barrel when it warms up

MagnetoSpeed makes a little barrel cooler to insert into your action. It does fairly well for me.

 

[MThuntr]

I've had some powders get real spikey at high temps...RL26, Tac, CFE223, and especially MagPro. Usually with loads that were hot to begin with so that's on me. MagPro was the only one that gave me fits when it was very cold. I try to develop loads in the middle temps but with "temp stable" powders. More temp sensitive, I've started doing load tests closer to 80 degrees just to see what they'll do when warm.

I have a 3D printed barrel chamber cooler with a USB that connects to a battery pack. Cools things off nicely. I can't seem to find the link but looks like there are plenty of options for load development in the heat.

 

[EastTNHunter]

I've had some powders get real spikey at high temps...RL26, Tac, CFE223, and especially MagPro. Usually with loads that were hot to begin with so that's on me. MagPro was the only one that gave me fits when it was very cold. I try to develop loads in the middle temps but with "temp stable" powders. More temp sensitive, I've started doing load tests closer to 80 degrees just to see what they'll do when warm.

I have a 3D printed barrel chamber cooler with a USB that connects to a battery pack. Cools things off nicely. I can't seem to find the link but looks like there are plenty of options for load development in the heat.

I’ve had RL26 go from no pressure signs at all at moderate temps to blowing primers in the 90s

 

[MThuntr]

I’ve had RL26 go from no pressure signs at all at moderate temps to blowing primers in the 90s

Yeah for being touted as temp stable it's moody when it gets warm. I really like the numbers it printed on the chronograph. Might have to grab some VV N570 which seems similar without the mood swings (or so I've been told)

 

[yakimanoob]

Will groups shot in cooler weather translate to good groups in hot weather and vice versa?

Yes.

The simplest situation is testing your loads in hotter weather than you're likely to encounter in the field (this is naturally the case for many hunter/reloaders since we're testing in the summer in preparation for fall hunts). In that case, you have nothing to worry about other than a potential slight correction for the lower velocities that may come with colder weather, but accuracy will be the same.

As already stated, with Varget you're unlikely to notice much of a difference anyway, unless your temperature swings are extreme.

That said, if you're seriously pushing the pressure maximums, shooting ELR and/or going for 1/4 minute levels of accuracy, or you only have the opportunity to do load development in cold weather and plan to hunt in very hot weather, I will leave it to more experienced minds to advise you.

For typical hunting applications, especially with Varget, I would not overthink it. Cheers!

 

[Doublecluck]

I’ve had RL26 go from no pressure signs at all at moderate temps to blowing primers in the 90s

RL 26 is dirty and unstable.

I’ve had good results with all the Hogdon extreme powders relatively. More recently been really impressed with vihtavouri powders. I ran N568 at the Nightforce ELR match in my 28 Nosler. It had a 10 shot sd of zero and showed a 2fps average change in 20 degrees hotter weather. By far the most stable cleanest powder I’ve ever ran. Never had a problem w h1000, Retumbo, h4350, varget developing in hot/warm/cold weather.

 

[Vanishe187]

Depending on your powder and how drastic temp changes are. Now there are very temp stable powders you can use. Ive reloaded for 30 years now. I can tell you powders like cfe223 and varget doesn't matter. I actually do most of my load development during summer when there is no hunts. I got a few lbs of h380 my cousin gave me. That powder you can see a big difference with temps. I use that for my 22-250. I usually test it when temps drop so I have accurate chrono readings. I belive it was something wild like 200fps or more difference. Which is why he didn't like that powder.

 

[N2TRKYS]

Developing hunting loads in the summer has proven dumb, regardless of powder used. I do all of my development during the temps that I will be using them.

I love RL26. I’ve never had any issues with it whatsoever.