What is a good powder that is relatively temprature stble? This is for a 243wssm Ar.
Any shared knowledge would be very appreciated.

Hodgdon Extreme powders.

Yep....

Is that it? What about varget or any of the RL powders?

Varget IS one if the Hodgdon Extreme powders.

RL-15 is much better than it used to be, due to being modified to make mil-spec, but still isn't in the same league as Varget or any of the other Extremes as far as temp-resistance.

H450

I have an AR 243wssm, and it loves varget and 95 gr nosler bts. Don't recall the charge weight off the top of my head. I am also using reloader 17 with very promising results. I have killed deer out to 602 yds with this setup. Olyarms 243 wssm upper with 24 inch stainless Ultramatch barrel, and Zeiss Conquest 6.5 x 20 x 50 in Badger Ordinance rings. I will shoot the Berger 90 gr match bullets in tiny little 1/4 inch clusters, but not at mag length though. It will print 85 gr spear btsp and 95 nosler bts in 1/2 to 3/4 of an inch all day. Enjoy

RE17 is supposed to be pretty temp stable.

I've yet to see much variation in my 6.5x47 with which I started using back last winter and continue to shoot through the year.

I will add that I too love the Extreme powders.

Alan

+1. Trying to make the switch from IMR 4350 to H4350 and everything seems to be going great!!!!

That's hilarious

Finally, someone caught on!!!

I could have said H870 too!

I did my own test using a freezer and and oven. I found that the Extreme powders were no more stable than any other powder. In fact, in the 7mm wby I was using, RL 25 was more stable than Retumbo or H 1000. The Vihtvuori powders are supposed to be very stable and they were more stable in my test than the Extreme powders. I am not saying my testing was perfect but it was convincing enough to me that I am going to use the most accurate powder for the given rifle rather than bending over backwards to make the extreme powders work. For my 7wby it was RL 25.

Do tell.

JimBobwsm,

That sounds fun. How long did the test take? If you don't mind would you post the procedure you used?

I placed ammo in the freezer and ammo in the oven and got the ammo to about 110 degrees. I experienced discrepancies of up to 130fps with the Extreme powders. The hot ammo grouped the best and had some noticeable pressure signs that were not experienced in the cold ammo. I went to RL 25 in the 7wby which gave the best velocity and accuracy and experienced velocity discrepancies of about 75fps on average.

Changing the temperature of ONLY the ammo isn't the same thing as shooting the rifle and ammo when everything is at the same temperature. This is the major flaw in most so-called temperatures tests. For one thing, the temperature of the primer can change in a few seconds simply from contact with the bolt face.

The only valid way to test powders is actually shooting the rifle and load at varying temperatures.

Temperature-stability also depends on the cartridge/bullet combination. Judging powders on the results from one cartridge and rifle doesn't mean much.

That makes sense JB. Several years ago I remember you guys talking about a warm chamber making a difference.

When Dober and I did our 'test' a couple Winters back we had cold rifles and pretty sure we even let them cool a little in between shots.
As you know it doesn't take long to chill a rifle with the action open standing in a rack. Especially with that Logan 'breeze'!

Anyway with H4350/H4831sc and R17 I wouldn't be worried with shooting at a deer out to about 400 yards at say 0F or above. Velocity was roughly 50fps lower with the Hodgdon powder(compared to 70F results) and maybe 75-100fps lower with R17. Seems like accuracy was off when it got colder.
I know for a fact a scope on a 300WSM becomes more fragile when it's much colder than that....grin



Should add that 400-500 yards is long range for me, I'm sure the guys that actually practice at real LR might notice even more of a difference.

We knew what he was talking about (or meant).

I have used retumbo in a 338 lm and rl22 in a 257 wby and 7mm RM and h4350 in a 243 win. I have done all load dev in the summer at ~80f, got accurate loads and chronographed them. I then shot and chronographed those loads in -30f where everything was that temp ( as in gun and ammo were in back of truck on the way to the range in the winter. 45 min drive). My retumbo load lost 30 fps, h4350 25 fps and the rl22 loads lost 150 and 120 respectively.

I use only h4350 and retumbo now for any hunting ammo where I'm out in the cold hunting. I will test h4350 in my 270 wsm this winter but I expect it to preform the same.

I often hear people say magpro or RLxx for highest fps but they are of no interest to me if they are slow in the winter where it counts for me. I go hunting when it's cold. Not when it's 80F.

Good point, Kman

I've been watching H1000 in the 7mmMashburn Super for a year now....it does not give the very highest velocities but is only 50-75 fps off Retumbo, but spreads are very low,and POI consistent winter to summer, out to 600 yards.

I have not touched the scope settings since the rifle was zeroed about a year ago.

I agree with John B on the temp thing,at least from what I can tell.....and noticed years ago that a powder that looks lousy in one cartridge, does well in another.....for example, I found IMR 4831 to be "good" in the 270 over various temps, but not so in the 7RM,where it lost velocity in the cold.

Sometimes, I think powders that give slightly compressed loads do better,but not sure why.

I ended up usuing Ramshot hunter in my 1000 yard light rifle.
My best load gave up 7 mil clicks from 850 to 1000 yards when the temp went from 80 to 35 degrees.
The Berger program told me I'd only loose 3 clicks on a 80 to 35 degree temp change.
My velocity at 80 degrees was measured at 2806.
I had to back it down to 2730 to get it worked out right.
dave

I recently found that I have about 3.5 lbs of H450 stored away. Don't remember why I bought it or what I'll do with it.

Bob

How hot your running your load may have some bearing on temperature stability. Or at least that was the conclusion that I came to when I tried a bit of the freezer testing. I found that the same gun with different loads of the same powder and different bullets lost velocity differently. I wish it was as simple as "X powder loses 4fps for every 10 degree temperature drop." Unfortunately, I do not think it is that simple.

I run h1000 in my 243 with 105's. Seems to be pretty stable and consistent. Shot a buck with it Friday with a 105 vld. I'm going to start working on an h1000 load for my 264 and 300 wsm too. I think a guy can cover most bases with Benchmark, h4350, and h1000.

Bb

AR Comp would be another powder to consider. In this test, it was twice as good as Varget for temperature stability.

http://snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2812538