Well, it's like this...

I use IMR-4350 in several different calibers. I use it in areas where the temperatures go up to 125 degrees and down to 55 below. I have never had a problem with it.

I was at the range today and a guy told me this powder is real temperature sensitive. Is this true? He suggested I use H4350. The load I'm using in my 338 Win Mag is real accurate using the IMR 4350, and I don't really want to change.

Opinions?

I would place some value on his warning , contiue to use the IMR4350 and if by some wierd chance pop a primer some day I'd re-evaluate. If you are following safe reloading practice you will not be in harm's way using that powder and your accuracy will not be changed, especially in your climate roger.

Develop your loads in warm weather and you will never have any pressure problems when the temperature drops.

These loads aren't max loads at all. I'm more interested in hunting accuracy. I'm just curious if I was hunting in 30 degree weather if it would effect the point of impact that much.

IMR4350 is neither exceptionally temperature sensitive, nor is it exceptionally temperature insensitive.

In some cases, H4350 is very temperature insensitive, and in others, exactly as temperature sensitive as IMR4350.

Hodgdon spins a good yarn about temperature insensitivity, and in some cases, the story is true. In others, it definitely is not.

IMR 4350's been a standard for a long time.

Changes in muzzle velocity and chamber pressure of cartridges with temperature changes have been there from the beginning, with all powders. Never was a big issue till Hodgdon claimed their Extreme powders were relatively insensitive to that, a claim which I'd take with a grain of salt.

JBabcock:

I live in Arizona, and IMR4350 is one of my favorite powders. I load it in 270, 35 Whelen, 375 H&H, just to name 3. Here in Arizona, we don't stop shooting just because the temperature reached 110'. So I guess if max loads were a problem when it gets hot, I would already be in the happy hunting grounds! LOL. Plus the IMR version has been around a lot longer than the H version.

Jerry

Thanks guys,

I'm relatively new to handloading, and this load is one of the first that I've put together for this rifle, (Model 70 SS Classic ), and it shoots excellent. Good groups and decent velocity. Velocity for a 5 shot average is 2916 with a SD of 21. It will shoot under an inch if I do my part.

So I'm going to stick with it.

JB:

I wouldn't consider 30 degrees here in the NW as much of a temperature sensitive scenario. As Steve Riccardelli pointed out, 55 below now that is temperature sensitivity.

I used it in MN winters and it did just fine, also well at the range in summer temps.

cheers and good shooting
seafire

I've tried several differant powders in the 6MM Rem , and have always come back to 4350 . The ball powders have been ok but in my rifle that 4350 just seems to work . This is at temps around 60-70 F at home along the coast of CA or at -10-30 F in the mountains of MT at 6500+ . For me its great .

JB
I used IMR 4350 for over 20 years and its a good powder...I tried H 4350 and my rifles liked it much better..Hodgdon has now bought out the IMR powder company so some changes may take place in the future..One thing I found with the IMR series is that it was not as consistent from lot to lot as the Hodgdon powder...As far as being sensitive to temp. changes, yes it is, a little, but probably not enough to detect in a hunting situation...

In my limited experience, IMR4350 has been more consistent from lot to lot than the H4350 has been. You can look at all the reloading manuals from 7 or more years ago till the newest batch and see the difference in what they recommend as max loads for H4350. The only pressure problem I've had with any 4350 powders (including AA4350) has been with the newest can of H4350 that I bought and did not work up loads as I should have. I don't live in a real extreme temp place so I can't speak to that. BM

Bill