Does anyone have pressure data and or velocity data about what happens with a powder like Rel19 or Hunter when the temperature goes from 70F (21C) to 120F (49C)?

either real data or Quickload data would be a help in trying to plan some new loads.

For a hypothetical case in a computer, try a powder that produces about 3100fps for the 185 Barnes TTSX in 338 WM.

Is there much difference predicted between Rel 19, Hunter, and Rel 17 with regards to temperature increase?

What increases should be expected in psi or in fps for this temperature spread?

The Norma Gunbugs Guide [1965] has a graph for a 180 gr 30-06 though powder is not id'd. From 68F-122 F pressure goes from 42630-42945 psi and velocity goes from 2680-2775 fps.
That should be fairly representative. Keep your ammo out of the sun and work up loads for the highest temperature you will see !

Yes, keep ammo out of sun, especially if one wants similar points of impact.

That is interesting data if reliable, because the pressure stays about the same while the velocity goes up 100 fps.

Any confirmation from Quickload?

quote:

42630-42945

Hard to picture a 95fps jump from only 315psi.

Just looking at QL
Rl19 70 3112 61839
120 3196 67771

Hunter 3115 61140
3193 67316

Rl17 3101 60216
3165 65615

H414 shows about the same amount. Even H4831SC

A heavy compressed load.
3063 61865
3153 67757

quote:

Originally posted by ramrod340:

quote:

42630-42945

Hard to picture a 95fps jump from only 315psi.

Just looking at QL
Rl19 70 3112 61839
120 3196 67771

Hunter 3115 61140
3193 67316


Rl17 3101 60216
3165 65615

H414 shows about the same amount. Even H4831SC

A heavy compressed load.
3063 61865
3153 67757

Thank you RAmrod.

I do have a question on the numbers. It is surprising to see
Rel19 70 gr for as much as 3112 61839.

Someone else had sent me a quote of quickload Rel19 76 grains for only 3026 57.3k psi.

Someone else sent 71.5 grains Rel17 for 3107 and 59.2k psi.

All for 338WM 185gr TTSX in 24" or 25" barrel.
I suppose one can set Quickload differently.

Thanks.

That was 70 deg not 70grs. I didn't list loads in my first post.

I ran QL using all std setting and a 24" barrel.
Rl19 was 78.75
Hunter was 77.75
Rl17 was 72.31

I simply set a load that gave me as close to 3100 from a 24".

Simply changing OAL from 3.34 to 3.32 can result in a few fps and several hunder # difference. Or a grain or 2 difference in case capacity. Key thing is most of them seem to add around 4-5000psi going from 70 to 120. So if you think wou will see that much temp then don't load to 65,000 at 70 because you might have issues at 120.

Thank you for the clarification on 70 degrees F!

Now things make sense.

And yes, those Quickload guidelines of about 4000-5000 psi are good reasons for using 60k psi as a realistic 'max' in hot climes for a calibre like 338WM.

Temperatures may sometimes be 90-100F while walking in the forest, but one should have some leeway for 120F. Fired rounds will heat a barrel quickly, too, and might lead to some sticky cases on a fourth or fifth round.

It also means that a gun whose point of impact changes with 100fps velocity might shoot differently at 7am from 2pm.

quote:

and might lead to some sticky cases on a fourth or fifth round

I would think they would need to sit awhile to heat up to 120 from barrel heat.

What I did find interesting is the HUGE bad press for RL powders and heat. Running the same test using H4831sc
75 grs (105%) load 2880 @ 49607 increase the tmp and it is 2971 @ 54203 Still a gain of 91fps and 4600psi.

Brass conducts heat fairly well, I don't think that they would need too many minutes in a chamber to get frickin hot.

Is there any powder that is "cooler" at 120F?
Quickload is supposed to say something about contributing to barrel heat, too, from a load. Yes?
How about good ol IMR 4831 or 4350?