Load testing in the heat??

So, this time of year when its 95* in the shade, your at the bench testing loads for this fall/Winters hunts. When I was shooting 400 yard clays, we would sometimes put our ammo boxes in an ice chest or at least in the shade to keep them "cool"

I'm shooting 42.4gr H4350 in my 6.5 Creed, 140/143gr bullets

will it make a hill of beans as far as higher pressures (velocity difference) now and in December?

Or am I overthinking AGAIN??

I don’t know about 4350 and should since I use it but some powders such R19 and 17 are very temp sensitive. I’m sure all would be fine hunting inside 150 yards. Summer to winter you may wind up hitting the next clay down. Believe me, if Varget worked well in everything I wouldn’t own anything else.

I think so. Extreme are very temp stable. Plus it will probably be 50 degrees in December.

For long range precision purposes, you should be aware that differences in DA and cartridge pressure will both make your shot require less elevation correction this time of year. For hunting inside 400 yards, it's irrelevant. For target shooting small targets at 600+, you should be aware of the conditions when you get your data and how different conditions later on will impact your trajectory.

Load development in the heat is the perfect time. If it doesn't over pressure now, it's good all year. Only one more step that can be made to ensure "bomb proof" ammo, and that is hot weather, as well as dip the cartridge in water, then chamber and shoot it.

I've shot The Heatstroke Open for 7 years now, and in 100° F, no shade for two days, and not much cooling time between stages. Let em rip!

(Just don't do it on 7th loaded brass)

A tip if I may, If you find a wide node in hot weather, try to use the charge of the higher side of the wide node so when the cold weather comes, you will decrease some velocity and still be inside the node. Just a heads up.

Good tip, Tack.

I've been loading and testing like a madman these last couple of months for these reasons. I I have ONE last load to verify, and I will be completely done with my rifles. I don't think I've been in this position since 1997.

I think I smell a rifle swap coming.

This is a good tip as well.

Good tip, I added the quite to the tips and tricks sticky

No powder is immune to temp sensitivity. But H4350 is less than others. Even during Jason's tactical match when it was 100-107 degrees I got 2 cases with slight gas leak around the primer pocket (H4350 is my powder for my 6.5x47). (And I even dialed my load down .4 grains from where it was.) Once I saw this, I put my ammo in my small 6 pack cooler to cool off. I didn't have an issue after that. I also kept my metal AI magazine in there, so it didn't get too hot to cook the rounds hotter.

So, can the heat effect your load- yes, of course. When it's 90+ degrees for load work up, and you go and shoot that ammo in 20-30 degrees, yes, you can see a difference in the accuracy, speed, and pressures. Shooting and testing in this heat helps to know where your upper limit of pressure is for sure, where you know you should be safe in the winter time. But there still can be a variation between the 2 temp extremes.

Positively true.

Some who have opportunity to take advantage of extreme temperature ranges have noted that many of these new powders exhibit excellent response to very low temperatures, but still will burn a little faster at the high end of temperature ranges.

One of the better powders in the 4350 range of burn rate is Re16, which is actually a double base extruded powder. It is more consistent that IMR 4451, which is single base. How Alliant pulled that off, I don't know...but to borrow a phrase from North Dallas Forty, better shooting "through chemistry!"

Reloader 16 and 23 are bad to the bone.

Yes they are but let’s not talk about that .... Shhhh

thanks everyone

So is 26. I'm using it in .280 and getting accuracy at 3000 fps with a 150 Partition, and I've gone higher with it, no problem. Also pushing 95 Partitions in a 6mm Rem, mild load at 3100. Want to keep that one tame to preserve throat and brass.

I've ran it in 22 creed but I'm not 100% sure on stability I had a speed up once but I'm not certain the cause yet.