Home Forums Reloading Big Game Rifles 7-08 Which powder RL15 or IMR4064 for temp swings?

I'm getting good accuracy with both IMR4064 and RL15 under a 140 Nosler BT. Any experience on which powder is less temp sensitive?

Pretty sure I read a while back the military was spec'ing re15 in 308 ammo.
But, if it was to thwart dessert heat I'm not sure if its still good when temps go sub zero.
I've also read that some powders can be very temp consistant in a certain cartridge but not so much in another. If re15 is a winner in 308 I'd like to "think" it would be good in 708.

Varget...oh sorry. That wasn't an option. It does well in my 7-08. I'm interested in hear other replies on those two powders.

Ramshot Big Game is reportedly fairly temp stable and about the right burn rate.

DF

Did a Google search using either powder and the words "temp sensitive" and tons of posts pop up. From what i read it would appear both are sensitive as you go warm to cold at a rate of about 1 fps per degree of temp loss.
Here's just one of many many reads....

http://forum.snipershide.com/snipers-hide-reloading/243262-rl-15-imr4064-temp-sensitivity.htmli

If you can find some, try H4350 between 46-48 grains.

Yeah, those Australian made Hodgdon Extreme series powders are about the best for lack of temp sensitivity.

Tried Big Game with 120's and 140's. Great speed, but accuracy was lacking.

I can't seem to find Varget and it would be a good temp stable powder.

CFE-223 is in the right burn range. I have some but have never used it in a .308. It's sort of a military type powder. Does anyone know how its temp sensitity rates?

DF

If you can find AR Comp... its like RL 15 but Temp Insensitive... burn rate is a hair quicker, but since Reload data is conservative, Rl 15 data has worked well for me so far...

Out of 9 responses 7 fail to answer the OP's original question.
??????

Why do members who do not know the answer feel they have to jump in?

Jim

When Hodgdon came out with their extreme powders they made a mistake in their "take the extreme tour" presentation.

They showed how great Varget was and in the same chart they showed IMR 4064 which had a 46 fps velocity change from zero to 125 F.

See page:
https://www.hodgdon.com/smokeless/extreme/page2.php#top

Don't know about RL-15's temperature sensitivity.

My vote is for 4064. My 7/08 loves 41.0 grains behind a 140 grain Ballistic Tip. That load yields some amazing groups for me. Have not had any problems with temp sensitivity with that load.

Not too bad. Thanks for posting. My temperature swings are not that extreme, so it looks like I'm fine with IMR4064. Mid 20's in winter through upper 90's in summer.

I'm running IMR 4064 but have not tested it throughly in "extreme" temps. Thus far it shoots great from 60-95 degrees. I plan on running this load for deer in Nebraska where temps can be frigid but usually around 30's.

Some of the RL series of powders are a little sensitive to temperature change. RL 15 is not. It is right in the ballpark with Hodgden's Extreme powders.

I have IMR 4064 and use it in several calibers. Great powder.

Hey, it's the Fire for goodness sake...

DF

Reloader 15 works great in my 7mm-08 with both 120 gr. and 140 gr. bullets. At temps from 15 degrees up to about 90 degrees, I have no appreciable changes in POI or in chronied velocity. Any variation is no more than I get between strings on the same day. There's my two cents worth..........

Not bad mouthing anyone's favorite powders, and I shoot all the above mentioned powders at one time or another. But if you haven't tried RL 15 in a 7mm-08, you may be missing out on a good shooter. I have owned five; a Ruger M77, a Remington M700, a Kimber 84M, and two Cooper Excalibers. RL 15 worked the best in all five. I don't know the odds of that happening, but I speak the truth.

Reloder 15 is indeed one of the less temperature-sensitive Alliant powders. It wasn't always, but maybe a dozen years ago was reformulated for U.S. military use. After that it was far less temp-sensitive than IMR4064 has ever been.

However, one thing that many if not most handloaders don't realize is that temp-sensitivity depends on the application. Even the Hodgdon Extremes are at their best in cartridge/bullet combinations that fit into their optimum burn-rate range. But Reloder 15 is very good with the bullets most hunters shoot in the 7mm-08. It probably wouldn't be as stable with 175's or even 160's.