Powder and the atmosphere

[300WSM]

I've been thinking about this for a few days and was curious what others think or have found.

What powders come to mind that seem to be highly sensitive to changes in the atmosphere and what have you found that seems to perform steady no matter what mother nature is doing.

For me a couple of the IMR's seem very immune to any changes regarding weather. I also have some powders that seem extra sensitive.

 

[dragger201]

That's why I use IMR 4350. I don't have a lot of time anymore for reloading and shooting. And I know from years of testing, that it will get the job done, fair weather or foul. For hunting here in MS it's pretty important, as I may be hunting when it's 18' or 80'...........and that spread may take less then a week to occur. Case in point........last weekend the temp dropped to freezing, yesterday we reached 81'. And the week before that it was literally 18'.

 

[R Flowers]

I do not have any scientific data to prove it, but in my experience I have found 760 to be the most sensitive to temperature change with 748 close behind. On the other end of the spectrum, I find most any of the Hodgdon Extreme powders to be quite insensitive to temperature changes.

 

[PJGunner]

I do not have any scientific data to prove it, but in my experience I have found 760 to be the most sensitive to temperature change with 748 close behind. On the other end of the spectrum, I find most any of the Hodgdon Extreme powders to be quite insensitive to temperature changes.

I haven't found W760 to be that much of a problem but then again, it usually doesn't get that cold here where I live and hunt. My last deer hunt which was almost 7 years ago now it was all of 32 degrees in the morning with a touch of snow and in the mid 60's by late afternoon. Seems to be about normal for Northern Arizona. In the southern part of the state one can end up hunting in 80 degree weather or stay home. I would imagine that if it would drop close to zero or some other low number that maybe I'd have a problem but so far? No problem. I went to the ball powders when I got tired of fighting those log types such as the 4350's and 4831's. That changed when I got the RCBS Chargemaster 1500 and I'm now renewing my acquaintence with H4350. One baall powder that has worked very well fo me in the .270 and .300 Win. Mag. is Winchester's long discontinued Magnum Rifle Powder. (WMR) I have a decent supply and the last time I hunted elk here in Arizona, it was a few degrees below freezing and I had no trouble taking down a cow elk at extreme range. (530 yards laser measured) I have to wonder if I've just been lucky or if that temp sensitivity might be a bit overblown?
Maybe it just doesn't get cold enough in my neck of the woods. :wink:
Paul B.

 

[300WSM]

IMR 4350 is one of them.
No matter the weather it just shoots with seemingly no variation. Ever.

IMR 4831 is another one that seems to perform right along with that.

 

[Mountain Goat]

IMR 4350 is one of them.
No matter the weather it just shoots with seemingly no variation. Ever.

IMR 4831 is another one that seems to perform right along with that.

I quit using I-4350 in my 280 because accuracy went south as the tempurature dropped below 40 or so. With that, I think that we take sample data of one and try to extapolate a powder as temperature sensitive or not. How do we know it isn't that particular rifle or that rifle with that particular load? If it were strictly the result of the powder, then my 30-06 would show the same results. All that happens to the '06 is a drop in velocity of about 60fps, which could be the chrono and not the powder.

My point, I feel that the "extreme" labeling by Hodgdon is mere puffery and brilliant marketing. What might be the most consistent powder for one person might also be the most inconsistent for another. There's no way someone or some company is going to go through the cost and effort needed jsut to dis-prove such as nonsense. Hodgdon stated it first, so they own it, and that's to their advantage. So, we just test our handloads, and hope they show consistency in all temperatures as much as possible.

 

[300WSM]

IMR 4350 is one of them.
No matter the weather it just shoots with seemingly no variation. Ever.

IMR 4831 is another one that seems to perform right along with that.

I quit using I-4350 in my 280 because accuracy went south as the tempurature dropped below 40 or so. With that, I think that we take sample data of one and try to extapolate a powder as temperature sensitive or not. How do we know it isn't that particular rifle or that rifle with that particular load? If it were strictly the result of the powder, then my 30-06 would show the same results. All that happens to the '06 is a drop in velocity of about 60fps, which could be the chrono and not the powder.

My point, I feel that the "extreme" labeling by Hodgdon is mere puffery and brilliant marketing. What might be the most consistent powder for one person might also be the most inconsistent for another. There's no way someone or some company is going to go through the cost and effort needed jsut to dis-prove such as nonsense. Hodgdon stated it first, so they own it, and that's to their advantage. So, we just test our handloads, and hope they show consistency in all temperatures as much as possible.

Interesting about the IMR 4350 in your case. I've never had that happen in several calibers from magnums to simple 08's and we can have some crazy changes in weather and pressure here. Which is why I always tell people getting into reloading that is a must have powder for the bench. The versatility and of course reliability.

Hodgdon throwing the extreme word on stuff is total market exploitation. I have first hand experience with the "extreme" stuff and it is far from being immune to changes.