Home Forums Reloading Big Game Rifles IMR 7828 Tempeture sensitive??????

Has anyone played with this one?

I want to use it in my 378 Bee but having second thoughts.

Lots of times Fotis. One of my favourite powders in 7MM Weatherby, .270 Winchester, .25-06 Rem & 7WSM. I live and hunt in Manitoba, and sometimes, well let's just say it can be cool in November during hunting season. Is 7828 temp sensitive? I suppose so, but I have not had any problem with it. I especially like the ssc version.

After this weekends fiasco with RL22 (heating up on each shot -- a lot!) I decided to try IMR7828 and H4831. That one I know for sure is extreme!

Sure can't speak for a 378 Bee, but in 270's, 30-06 and 30-06AI, IMR 7828 showed showed a fair amount of velocity loss in single digit temps (I let the rifle and ammo "cold soak" over night with the truck sitting outside.

Another thing about temp sensitive powders, ES seems to usually increase quite a bit. I've seen warm weather loads in a 270W and RL22 with a ES of ~30fps go to 100+ ES in single digit temps.

Looking in my chrono notebook when I tested this about 5 years ago:
In my 30-06AI, I lost 61 fps averaged from a 10 shot string from 80 degrees to 5-10 degrees air temps. ES goes from 31 fps to 58 fps. Edited to add: This is with IMR4831

Casey

I have a near max load in a 7MAG that works great when it's 45 and cloudy/rainy out. When the temp gets to 65+ and sunny the velocity climbs 30fps and I'll get an extractor mark on the case. So I would say yes, very much so in my case.

Thank you for the input fellas

It does carry the claim, but it still swings a bit with temps. Last I checked H4831 in a 40deg swing I had a .5 grn difference. 300WM, 190SMKs, sorted and prepped WW cases, 215GMs. Adjustments settled the avg MVs, SDs, and brought the accuracy back in. Yes, same lots of all.

Fotis, H-4350 is your friend firing the 235/250's in the 378 WBY, use to load 250 Sierra's to 3350 w/ IMR 4350, switched to H when it came out and never looked back, excellent accuracy, uniformity, and fits in the case without compression.

Gunner

Man!!!!!!!!! PM me your loads!

PM sent,

Gunner

Tango Mike~