Powder temperature input?

[BillyGoatGruff]

Hey Guys,

Do you guys use the powder temp input in your ballistic calculator? I notice that if I enable that feature it changes the solution by 4 moa at 750 yrds. That's quite a bit of difference. that's for a 30 deg temp.

Just wondering if I should use it. I don't think I used it during my practice sessions and all my solutions were spot on, of course it was about 60+ deg most the time.

Thanks,

 

[Skeeter]

I'm no expert and haven't shot at that distance before, but I have definitely noticed changes in POI and pressure with 30 degree temperature changes. It varies depending on the temperature sensitivity of different powders. I have a load for a 300 wsm that shots great at cooler temps, but above 60 degrees I start seeing pressure signs on the case head and poi change out to 400.

 

[bobhunts]

What powder are you using? This would be a factor. Some are more temperature sensitive than others. I am not using a calculator like you are.

 

[BillyGoatGruff]

Mostly retumbo and H1000, supposedly not temp sensitive powders per hodgdon.

So in my shooter app, If I check the powder temp box and it's 25* out then is reduces my velocity quite a bit. I need to do some chronoing at cold temps and see what the numbers are. Been to busy to do any kind of shooting lately though.

Thanks, BGG

 

[pyroducksx3]

Don't use the powder temp with those powders, it will throw your data way off. Sometimes when I add a new rifle and i dont have service it put that powder temp field in. My calculations are always off its it's checked

 

[CDNPO]

Mostly retumbo and H1000, supposedly not temp sensitive powders per hodgdon.

So in my shooter app, If I check the powder temp box and it's 25* out then is reduces my velocity quite a bit. I need to do some chronoing at cold temps and see what the numbers are. Been to busy to do any kind of shooting lately though.

Thanks, BGG

Put a box of reloads together, throw half in a bag with a hot water bottle and half in a bag with an ice pack. Hit the range and see what the velocities look like. Then you can decide if you need to true your data to the temp of the powder or if it is as stable as the Hodgdon Extreme line advertises.

 

[8nbait]

It is very unlikely you will need to make any corrections with the Extreme powders like Retumbo, H1000, H4831, H4350, Varget.
I have tested them in several cartridges and the most I have gotten going from 0 degree ammo to 90 degree ammo is 20 fps difference, usually less.
Several of the Big Game and Reloder powders I have tested have had 100 fps or more differences.

My normal test is to put 3 rounds in the freezer over night and keep 3 rounds in the house. I like to do this when it is very cold out.
The next morning I put the three frozen rounds in a cooler with ice or in a container in the back of the truck if it's cold enough and the 3 rounds from the house on the defroster of the truck on the way to the range (they get pretty hot up there)

When I get to the range I shoot the cold rounds first out of a cold rifle that has been in the truck over night. Then I wait a couple minutes so the rifle is warm but not hot and shoot the 3 rounds that have been on the defroster with the truck running since I left the house.

I did this test this morning with RL26 in a 7 mag, it was 1 degree out this morning and I had a 47 fps average difference between the average of the cold and hot rounds, not terrible but I won't use that powder primer combo for hunting.

You can get about a 90 degree difference this way and it really shows how powders react to temp swings. If I get more than 30 fps swing I won't use that powder for hunting.

 

[BillyGoatGruff]

Good info guys, thanks!

BGG