Home Forums Reloading Big Game Rifles temp-sensitive powders and Extreme powder questions

Mule Deer states in one of the posts in Hunters Campfire or Gunwriters forum that he no longer uses temp-sensitive powders in his varmint rifles. I was wondering how many of you guys buy Hodgdon Extreme powders only of you are going to shoot in the summer and winter time? For example I have the H335 powder and this is obviously not an Extreme powder and I am using this now but know when summer approaches I will have to test my favorite load and adjust accordingly. This is for a varmint rifle but this applies to big game rifles also.

I shoot all of my rifles year round, and I don't load with any powders that are temp. sensitive.

It depends.

I have some loads that I use in spring and fall that are temperature sensitive. But it doesn't matter, because they are for days that are not too cold or too hot. If I didn't do that, I'd have powder that I would never use up.

Wherever I can, I use less sensitive powders.

A powder that is less sensitive is usually only matched to a single cartridge geometry.

For a LOT of years, I only used IMR4350 in my 30-06. Hey! It worked well. My temperature swings went from about 70*F to -35*F. (Load development was at the high end.) -35*F was the coldest temp I ever shot anything at -- call me a sissy. I loaded to safe loads at the higher temps, and never had a problem on game. At that time, I was using 58.5 gr of IMR4350 with a Hornady 165 gr BTSP. I have since backed it down to 57 grains because I found it was a bit more accurate, and it still killed moose, bear and deer with aplomb.

IMO loads should be worked up for the temps normally expected for the time of year it will be used for regardless of powder being an extreme or not.

Case in point is that a load worked up with 8208XBR (which is supposed to be temp stable) at 50 degrees was causing hard bolt lift and fail to extract at 95 degrees. It was a max book load for 223. Have had that issue to some degree with max loads of benchmark.
335 is one powder that I will not approach max on a hot summer day at all. But then again I dont shoot 335 at any temp over 50 anymore either.

I try to work up hunting loads in hunting temps but that can be a challenge in a place like Mississippi where you've got 90+ degree temperatures and 80% humidity about 8 months out of the year. Many times it won't get into reasonable temperatures until the first week of November and our deer gun season starts around the 20th, that's too close to be working up loads. The season ends Jan 1st and it'll start getting hot again about the first of April. Basically that leaves February and March to work up loads for the next year and usually I'm busy with other stuff after months of hunting.

I shoot ruminants with 70 gr H4350, 140 gr Nos Bal Tip, in 7mmRM 3400 fps out to 500 yards
I shoot rodents with 15 gr Blue Dot, 35 gr Vmax, in .223 3500 fps out to 200 yards.
I shoot game birds with factory 12 ga out to 70 yards
I shoot coons with 29 gr CCI 22 CB shorts in a rifle with a 24" barrel 760 fps out to 6 inches.



I load 60 some other cartridges, but those are my "go to" loads for the past couple years.

from what has been stated it will be better to use temp-sensitive loads in the fall and spring and then the Extreme powders in the hot cold months. that way I will not have to re-test my temp-sensitive loads in the summer/fall. Should not be a problem when logs are kept for each rifle. But I think down the road it may be best to keep all rifles on the Extreme powder if the rifles shoot them fine that way these can be used all season.

Mr. Barsness has stated that some powders that are not known as extreme powders can and do display remarkable temperature tolerance in certain cartridges. Hornady claims that H-335 is temperature tolerant in the .458 Winchester magnum and the .458 Lott. My own experience shooting full power .458 Winchester magnum loads confirms this. With 500 grain bullets and a stout charge of H-335 powder, there was very little velocity difference between Alberta summer and Alberta winter shooting. I was not shooting at 20 or 30 below. But it was still winter in Alberta. When I tried shooting in very cold temperatures, the reticle in my fixed power scope broke. Too much shock for the cold and stiff reticle.

I was preparing for an upcoming Cape buffalo hunt in April a few years back, so I worked up loads during the winter. Solids and softs hit within 3\4 of an inch from each other: winter and summer. A good 2150 fps across the screens each time.

I annealed the cartridge case after each firing. The flash holes were deburred, and a firm crimp was employed from a Lee factory crimp die. Neck tension is a real concern in straight wall magnum cartridges such as these two .458 numbers. If I went without annealing, by the third firing, I could twist the heavily crimped bullet by hand. Accuracy, reliability, and dependability, went out the window.

This is a little surprising to me.
I have never annealed a case and never would bother with it. What I have learned however, is that when a bullet can be hand turned, in all my cases, it has always been an illfitting set of eating dies. When I changed dies, the issue disappeared in all cases.

I think dies are cheap enough that spares are always a good idea and can teach a lot in terms of what manufacturing precision really is.

John

When I lived in Washington I would work loads in the winter. Usually 40 deg range. I noticed they would shoot a little high. Mostly likly due to higher pressure in the Montana summer heat. I tried some of the extreme powder an didn't see much difference in the field. There may be some difference on paper but I never really tried ,just went back to good ol win748

AA2700 say in the Swift I'd expect to be sensitive to high temperatures either ambient or hot barrel. But I don't think TAC and Varget and such are quite so well suited to the Swift so I'm still inclined to go with 2700 for reasonably warm days in high desert country where it's not too hot. Maybe one of the newer powders I've never worked with will be the new #1 in the Swift. Suggestions for an extreme powder in the Swift?