H-1000 velocity variation/air temp value??

[helidriver72]

So I've got the Shooter app on my iPhone which I really like, my question is does anybody have a fps per degree of outside air temperature increase or decrease value for H-1000?

I'm running 89 grains in my Edge.

Thanks for any input guys, I know H-1000 is an extreme powder and doesnt vary a lot but the program has this feature and I figured I should make use of it.

 

[BrentM]

Excellent guestion. I am using Retumbo and not that feature on my Shooter program. So far I have shot from 10F to 45F without a temp correction and the rounds have been dead on. It will be interesting to see what happens when it gets to 60 in another month or two. I have no clue what number to put in there either.

 

[Joe King]

I don't use as it changes things on the app more than they really change, I think your better off just ignoring that feature with H1000, Retumbo, Varget, Magnum. even rl22 is more stable than that feature allows for

Here's how it works though
sean.kndy.net/shooter/manual.php
Powder Temp - This is an optional input and should only be entered if you also entered an MV Variation. This is the base powder temperature and should coincide with your Muzzle Velocity. So as in the example in the "MV Variation" field description above, you'd put 55deg here and 2850fps in your "Muzzle Velocity" field (or you could be 57deg here and 2855fps in Muzzle Velocity, doesn't matter). Now when you run a calculation using this ammo profile, there will be an option to enter current Powder Temp. If you were to specify say 65deg for powder temp, Shooter will automatially raise your MV to 2875fps.

 

[helidriver72]

I don't use as it changes things on the app more than they really change, I think your better off just ignoring that feature with H1000, Retumbo, Varget, Magnum. even rl22 is more stable than that feature allows for
.

The way I understand it I can put in 1 fps per 10 degrees of air temp change if I want so I don't think it will change things more than necissary. I'm just looking for that value to input. Thanks for the reply though.

 

[BrentM]

I believe it is fps/degree. So you would have to input .10 to get 1 fps change per every 10 degree's.

There is a video on here where they did a temp test. They put 5 rounds in a cooler with ice and then 5 rounds on the table in the sun. I think the temp in the cooler was 30 and the outside temp was 90. They shot 2 groups of temp stable and 2 non-temp stable. Pretty sure it was gunwerks, as they use Hogdon extreme only for their rifles. Anyway, the spread on the temp stable was something like 10 fps. The non-stable was 50 I believe. Would have to search the vid section and find it.

 

[Joe King]

The way I understand it I can put in 1 fps per 10 degrees of air temp change if I want so I don't think it will change things more than necissary. I'm just looking for that value to input. Thanks for the reply though.

Yea your right, I think this is more of what your looking for
July 2010 Barnes Bullet-N | Barnes Bullets

 

[Deleted member 112929]

Excellent guestion. I am using Retumbo and not that feature on my Shooter program. So far I have shot from 10F to 45F without a temp correction and the rounds have been dead on. It will be interesting to see what happens when it gets to 60 in another month or two. I have no clue what number to put in there either.

I don't use as it changes things on the app more than they really change, I think your better off just ignoring that feature with H1000, Retumbo, Varget, Magnum. even rl22 is more stable than that feature allows for

Here's how it works though
sean.kndy.net/shooter/manual.php
Powder Temp - This is an optional input and should only be entered if you also entered an MV Variation. This is the base powder temperature and should coincide with your Muzzle Velocity. So as in the example in the "MV Variation" field description above, you'd put 55deg here and 2850fps in your "Muzzle Velocity" field (or you could be 57deg here and 2855fps in Muzzle Velocity, doesn't matter). Now when you run a calculation using this ammo profile, there will be an option to enter current Powder Temp. If you were to specify say 65deg for powder temp, Shooter will automatially raise your MV to 2875fps.

If I'm hearing this correctly I should ignore putting any type of MV Temp correction into my Kestrel since I am using IMR-4064 in the 308 and H1000 in the 300 Win Mag. What are your thoughts?

 

[BrentM]

If I'm hearing this correctly I should ignore putting any type of MV Temp correction into my Kestrel since I am using IMR-4064 in the 308 and H1000 in the 300 Win Mag. What are your thoughts?

4064 is not temp stabile like the extreme lines. Here is chart of FPS per degree

 

[Deleted member 112929]

4064 is not temp stabile like the extreme lines. Here is chart of FPS per degree

Why is there such a big difference on the H1000 line between .21 and 4DOF of .56. That is huge.

 

[Wedgy]

The problem with using this feature is that the increase isn't linear, meaning it may be .21 FPS per degree from say 20F to 80F but above 80F it may change to .71 FPS per degree. I shoot in the desert heat well above 100F and most powders go nuts above ~the mid 80'sF but H1000 is pretty solid as is Varget & H4350

 

[BrentM]

Why is there such a big difference on the H1000 line between .21 and 4DOF of .56. That is huge.

I don't use the 4dof so I can't say for sure why the difference. I'd have to look into it.

what these charts don't take into account is the size of the cartridge and the charge weight. I know that sounds a little off but the more of everything you have to burn it can change the overall low density figure and have an effect on the feet per second per degree. Additionally if you're running a max powder charge or a high fill rateYou may see a Bigger change with the extreme temperatures mostly with the heat. Generally most of us operate in the middle of the temperature range and the numbers work fine.

 

[BrentM]

On the chart I use RL 26 and rarely see any velocity variation under normal temperature range. So I'm not convinced that chart Is overly accurate for my cartridge choices. I think you have to do your own testing and field trial to dial it in

 

[Deleted member 112929]

I don't use the 4dof so I can't say for sure why the difference. I'd have to look into it.

what these charts don't take into account is the size of the cartridge and the charge weight. I know that sounds a little off but the more of everything you have to burn it can change the overall low density figure and have an effect on the feet per second per degree. Additionally if you're running a max powder charge or a high fill rateYou may see a Bigger change with the extreme temperatures mostly with the heat. Generally most of us operate in the middle of the temperature range and the numbers work fine.

I'm just trying to replicate factory loads, MV with COAL. We are not going to get into all this ( how far off the lands and groves is the ojive of the projectile ) All my stuff need to fit into the magazine of an AR10 and when it comes to my 300 WIN MAG, well, I have to be able to hit what I need to at any range using off the shelf Hornady 200GR ELD-X.

 

[milo-2]

The problem with using this feature is that the increase isn't linear, meaning it may be .21 FPS per degree from say 20F to 80F but above 80F it may change to .71 FPS per degree. I shoot in the desert heat well above 100F and most powders go nuts above ~the mid 80'sF but H1000 is pretty solid as is Varget & H4350

This right here. I believe case fill plays hard in this equation also. So my 1 fps change per degree with a 102% fill may not be close to yours with an 87% fill.
Unless you are under time constraints, sometimes it is easier to build more profiles in your app to match actual conditions, if you know they are right.