IMR-4064 Powder Temp Sensitive or Not ?

[3Sigma]

Just one data point, but this is real world results for me. My hunting load in my 30/06 is 47.9gr of 4064 in Lapua Brass, Hornady 178 ELD-X, loaded to a COAL of 3.334 inches. Velocities measured from a Magnetospeed V3. These are 10 shots each, same load fired in 2 different temperatures. Just a note - I try to keep the temp of the cases in line with the ambient temperature so I don't skew the results (i.e. don't let them bake in the sun and warm up)

At 95 degrees, I'm at an avg of 2781 w/ ES of 11, SD of 5.7.
At 65 degrees, I'm at an avg of 2741 w/ ES of 17, SD of 7.6

So for me the MV variation is 1.33. That's what I use in my ballistic solver. Just like anything else you can't rely on the numbers floating around such as those posted on the temp stability chart above. You have to actually get out and test w/ your equipment and components. I wasn't aware of the reformulation, but all my powder is less than 10 years old.

As a comparison, I came up with 1.00 MV variation from H3450 in my .243 load. .83 MV variation from Varget in my 6 Dasher load.

From what I understand, all loads are temp sensitive as you get towards the hot end of the spectrum (of course some more than others). Where the extreme powders really shine is going from hot to cold.

The last paragraph here. I had a hot load of 22-250, developed at 40F. Shooting at 92F, too hot of a load. I use it and H380 now, but I don't push it like that anymore. Almost couldn't get the bolt open.

I use 4064 in my 308s all day, and I set those for accurate loads, not speed, and never had an issue.

 

[Mike402]

The last paragraph here. I had a hot load of 22-250, developed at 40F. Shooting at 92F, too hot of a load. I use it and H380 now, but I don't push it like that anymore. Almost couldn't get the bolt open.

I use 4064 in my 308s all day, and I set those for accurate loads, not speed, and never had an issue.

I made that mistake as well back in the day. I worked up a hot .308 load with Flatline 180s. Super low ES/SD and very accurate. Temp that I worked it up in was low 70s. Then I took it to a precision rifle class in the summer and temps got up to high 90s and I was blowing primers and accuracy went to shit. I had to resort to keeping my ammo in my coleman cooler to keep the temps around 70ish.

 

[Uncle Ed]

• https://en.wikipedia.org/wiki/7.62×51mm_NATO#cite_note-special_ball-45
• Cartridge, caliber 7.62mm special ball, long range, MK 316 MOD 0 (United States): A 175-grain round specifically designed for long-range sniping consisting of Sierra MatchKing hollow-point boat-tail projectiles, Federal Cartridge Company match cartridge cases and Gold Medal match primers. The propellant has been verified as IMR 4064 (per NSN 1305-01-567-6944 and Federal Cartridge Company Contract/Order Number N0016408DJN28 and has a charge weight per the specs of 41.745-grains

 

[Doom]

One item to keep in mind is the higher the load pressure you use the more likely you are to see large variations in velocity and pressure at higher ambient temperatures.

I have seen data for test 4064 that actually showed a negative coefficient but I can't find the link right now.

 

[Uncle Ed]

The military went from RL15 a double base powder to IMR-4064 a single base powder for their Long Range Sniper ammunition. This was due to the wide temperature variations in Iraq and Afghanistan. Other powders may have had less temp sensitivity but they are made offshore. And IMR-4064 is made in Canada by General Dynamics Weapons Division.

The ammunition below was loaded with RL-15 powder and the newer MK 316 MOD 0 is loaded with IMR-4064.

• Cartridge, caliber 7.62mm, NATO, ball, special, M118LR (United States): 175-grain (11.3 g) 7.62×51mm NATO match-grade round specifically designed for long-range sniping. It uses a 175-grain (11.3 g) Sierra Match King hollow point boat-tail bullet. Produced at Lake City Army Ammunition Plant. The propellant's noticeable muzzle flash and temperature sensitivity led to the development of the MK 316 MOD 0 for special operations use.

 

[D-4297]

On Thursday , I shot two 20 shot strings , with sighters at BA , at 600 yrds...Conditions were calm , with 0 - 3 mph winds . First string was a 198 - 7x , and temp was 57F . Second string was a 196 - 6x and temp was 60F . Load was Lapua srp , Rem 7 1/2 BR primer , 45.3gr of A-4064 behind a Berger 185gr Jugg OTM . Velocity was approx. 2,740 w/ SD-9 , ES-14 . SD for second string was also 9 , but the ES went up to 16 . A couple of faster rounds in the second string . Very consistent performance for both strings . Checked all brass , and no signs of pressure , flattened primers in any rounds . Rifle is a Kelby Panda F-TR , w/KTR stock , 30" 1-10T Krieger 5r , Jewel set at 4 oz. , Duplin Bi-pod ,and Vortex Golden Eagle . Recoil reaction did tell me I may want to soften it up as temperatures increase towards the summer months though .

 

[D-4297]

Kudo's to @Uncle Ed for posting that information concerning both the Mil-surp data , and the changes . I looked everywhere and couldn't find it , and thought I was losing what little mind I have left .

 

[Gabe22BR]

Stick powder- isn’t spherical ball powder.!!!
Uncle Ed needs to do more research..

I’ve got the same book...

 

[Timberyote]

I read the Alliant web site and got the load data, with RL15, for the original M118LR, loaded to a velocity of 2700fps, then within 3 months the info was removed. I guess that they found that the ammo was too hot for Iraq, so they dropped the charge about 2 gr along with the velocity.

My log shows that the original load (mine) chrono'd at 2699fps in May of 2008 and the same load, same batch chrono'd at 2755fps in Aug 2008. Temps were not noted but it was hotter in Aug.

 

[johara1]

Just one data point, but this is real world results for me. My hunting load in my 30/06 is 47.9gr of 4064 in Lapua Brass, Hornady 178 ELD-X, loaded to a COAL of 3.334 inches. Velocities measured from a Magnetospeed V3. These are 10 shots each, same load fired in 2 different temperatures. Just a note - I try to keep the temp of the cases in line with the ambient temperature so I don't skew the results (i.e. don't let them bake in the sun and warm up)

At 95 degrees, I'm at an avg of 2781 w/ ES of 11, SD of 5.7.
At 65 degrees, I'm at an avg of 2741 w/ ES of 17, SD of 7.6

So for me the MV variation is 1.33. That's what I use in my ballistic solver. Just like anything else you can't rely on the numbers floating around such as those posted on the temp stability chart above. You have to actually get out and test w/ your equipment and components. I wasn't aware of the reformulation, but all my powder is less than 10 years old.

As a comparison, I came up with 1.00 MV variation from H3450 in my .243 load. .83 MV variation from Varget in my 6 Dasher load.

From what I understand, all loads are temp sensitive as you get towards the hot end of the spectrum (of course some more than others). Where the extreme powders really shine is going from hot to cold.

Now do the same test at 40 degrees you will get the true picture. Compare them to your first results, from 60 to 40 is a big loss. The so called extreme powders drop 1FPS per degree..... jim

 

[D-4297]

Good suggestion , @Johara . But I'm not gettin up at 3:00 a.m. to shoot in the dark to get 40 degrees . It's usually closer to 50 by daylight here now , and BA has a time limit on when we can send rounds down range . My main focus in posting the original question was based more towards temps going up . In February , we could be in the high 70's to low 80's , and it only gets worse from there till maybe , November . Welcome to Arizona ....Now , GO HOME !

 

[Uncle Ed]

Stick powder- isn’t spherical ball powder.!!!
Uncle Ed needs to do more research..

I’ve got the same book...

Gabe22BR

I didn't say RL-15 was a ball powder or spherical powder I said it was a double base powder. The link below is the MSDS sheet for RL-15 and it shows the powder contains Nitroglycerin, meaning a double base powder.

https://www.alliantpowder.com/resources/sds.aspx

https://www.alliantpowder.com/downloads/sds/Reloder_Series_SDS.pdf

 

[johara1]

Good suggestion , @Johara . But I'm not gettin up at 3:00 a.m. to shoot in the dark to get 40 degrees . It's usually closer to 50 by daylight here now , and BA has a time limit on when we can send rounds down range . My main focus in posting the original question was based more towards temps going up . In February , we could be in the high 70's to low 80's , and it only gets worse from there till maybe , November . Welcome to Arizona ....Now , GO HOME !

Around here it doesn't get up to 40 degrees this time of year.... LOL..... jim

 

[Mike402]

Now do the same test at 40 degrees you will get the true picture. Compare them to your first results, from 60 to 40 is a big loss. The so called extreme powders drop 1FPS per degree..... jim

yep as others have pointed out, out here in the desert, the annual temp swing that I would be shooting in ranges from 100 to about 60. I went out each time with all 5 of my rifles and got MVs at those two different temps. I would be curious to see where it would be at in the 40s though. Would be interesting to see if the same formula held up between 60-40

 

[johara1]

It seems that the extremes at each end are the problem, not in the 60-85 area as much..... jim

 

[D-4297]

OK , sports-fans . Here the answer to the million dollar question . Drumroll please .....I shot the other morning using the same load and the temp was 46F for the first string . Shot a 188 - 2x at 600 yards , with a MV of 2,630 - 2,640 . Aprox. forty minutes later , I shot a second string of 195 - 10x , and temp was 59 degrees . Winds were 0 - 3 mph and consistent for both strings . This confirms for me , the Army research regarding lower velocity at lower temperatures , as this load was developed at 75 - 80F , and showed a MV of 2,740 - 2,750 in that temp zone . Other testing data shows that MV increase in the higher temperature ranges is not as extreme , so I could use this powder and load in our summer temps by reducing the load .02 - .04 grs , or until I got it down to the 2,740 MV range . Thanks for all the input on this , because we're all scrambling for alternatives to our usual powders , and it is a major PITA to have to develop a new load , with a new powder when you're startin to count primers with every round fired .

 

[Ned Ludd]

OK , sports-fans . Here the answer to the million dollar question . Drumroll please .....I shot the other morning using the same load and the temp was 46F for the first string . Shot a 188 - 2x at 600 yards , with a MV of 2,630 - 2,640 . Aprox. forty minutes later , I shot a second string of 195 - 10x , and temp was 59 degrees . Winds were 0 - 3 mph and consistent for both strings . This confirms for me , the Army research regarding lower velocity at lower temperatures , as this load was developed at 75 - 80F , and showed a MV of 2,740 - 2,750 in that temp zone . Other testing data shows that MV increase in the higher temperature ranges is not as extreme , so I could use this powder and load in our summer temps by reducing the load .02 - .04 grs , or until I got it down to the 2,740 MV range . Thanks for all the input on this , because we're all scrambling for alternatives to our usual powders , and it is a major PITA to have to develop a new load , with a new powder when you're startin to count primers with every round fired .

Am I reading your post correctly? The difference in velocity for the exact same load of IMR4064 at 46 degrees and 75 degrees was ~100 fps (2640 fps versus 2740 fps)? No powder known to man is completely immune to the effect of temperature on velocity, but that seems to be an extraordinarily high change in velocity for a single base powder like IMR4064. I could easily envision a change in velocity of 10-15 fps over an ~30 degree temperature swing, but 100 fps? That's not so great. I also gather from your post that the temperature sensitivity appears to be lesser in a higher temperature band. In other words, the change in velocity with respect to temperature is not linear. I have observed similar responses with other single base powders. Nonetheless, a 100 fps swing over ~30 degrees that falls the range of cool fall temps to very moderate spring/summer temps (from ~45 to 75 degrees) is pretty disappointing for IMR4064 powder. I have never used 4064, but would not have guessed the temperature-induced velocity differential would be nearly that high. Thanks for sharing your results.

 

[D-4297]

You're welcome , Sir . I was also shocked when the numbers came up , on both a LR and my Magneto-Speed.. I had to look twice to convince myself of what I was seeing . Humidity was a bit higher than normal for Phoenix , as it had rained about five hours before , and small lakes were formed in front of some of the birms , but that should have had only a minimal effect , at best . I will add to the data as temps warm up out here , and take it into the summer season , so we all have a better perception of this powder .

 

[johara1]

OK , sports-fans . Here the answer to the million dollar question . Drumroll please .....I shot the other morning using the same load and the temp was 46F for the first string . Shot a 188 - 2x at 600 yards , with a MV of 2,630 - 2,640 . Aprox. forty minutes later , I shot a second string of 195 - 10x , and temp was 59 degrees . Winds were 0 - 3 mph and consistent for both strings . This confirms for me , the Army research regarding lower velocity at lower temperatures , as this load was developed at 75 - 80F , and showed a MV of 2,740 - 2,750 in that temp zone . Other testing data shows that MV increase in the higher temperature ranges is not as extreme , so I could use this powder and load in our summer temps by reducing the load .02 - .04 grs , or until I got it down to the 2,740 MV range . Thanks for all the input on this , because we're all scrambling for alternatives to our usual powders , and it is a major PITA to have to develop a new load , with a new powder when you're startin to count primers with every round fired .

This is very similar to my findings with the extreme powders also from 60 degrees and lower it will loose 1 fps. per degree...... this real world test where everything is the same temperature ..... just like a match..... jim

 

[Chuckhunter]

You're welcome , Sir . I was also shocked when the numbers came up , on both a LR and my Magneto-Speed.. I had to look twice to convince myself of what I was seeing . Humidity was a bit higher than normal for Phoenix , as it had rained about five hours before , and small lakes were formed in front of some of the birms , but that should have had only a minimal effect , at best . I will add to the data as temps warm up out here , and take it into the summer season , so we all have a better perception of this powder .

D-4297 You made a point about humidity, in the last year or two I have been paying a lot more attention to that as I seem to experience greater velocity swings with a large humidity change than with a 20" F. temperature change. I shoot either a Dasher or a 6Bra here in Northeast Pa.( Williamsport) at 1000yds. and my loads don't change velocity enough to take me out of tune with a 20-25" temp. change unless there has been a relatively substantial humidity change, it's then that some bad things generally occur. Don't know how many others have experienced this but I have, at least with the calibers and equipment that I have been shooting.