H4350 temperature sensitivity test

[ballison]

OK, I was really bored today so I got to do something I’ve been meaning to for a while. I ran a crude temperature sensitivity test on Hodgdon’s H4350 powder. I know those statisticians out there will eat this alive, but it is what it is. Here are the controls and results of my test.

Remington 260
Lapua brass
SMK 142
43.2gr H4350
CCI 200 primers
Environmental conditions-45deg, 70% humidity, 29.0”Hg
Velocity measured with Magnetospeed V3

For the cold rounds, I placed them in my freezer for about 4 hours. Then I wrapped them in a cold pack and put them in a cooler for the trip to the range. I used a remote meat thermometer to monitor the temp.

For the warm rounds, I simply kept them in the house in an ammo box. I kept a regular thermometer in the box to make sure the temp didn’t change much before they were shot. It may have dropped a degree or two, but no more than that.

I also had some BR2 primers, and wanted to see how they compared to the CCI200s, so I included that data also.


CCI200 @ 70 F
2823, 2829, 2824, 2832, 2833, 2835, 2837, 2833, 2841, 2833, 2827
Avg=2831, SD=5.4, ES=18

CCI200 @ 10 F
2804, 2802, 2811, 2807, 2824, 2801, 2808
Avg=2808, SD=7.8, ES=23

BR2 @ 70 F
2842, 2842, 2834, 2836, 2855, 2844, 2834
Avg=2841, SD=7.4, ES=21


Just looking at the averages, the velocity dropped 23 fps over a 60F temperature change, or .38fps/deg. Make whatever conclusion you want, but that seems pretty temperature insensitive to me.

 

[dmoran]

Thanks for sharing your report !.!.!
Last time I conducted one with H4350 was from a 6Dasher that went: 34-fps in 88-degree spread
As you, just my own personal test and results.
Donovan

 

[Terry]

Nice job!

Thanks!

Terry

 

[rockcreek1]

Thanks for taking time to do the test. Awesome results.

Jim

 

[jlow]

How long did you let your barrel cool between firing and how long did you let the round sit in your chamber before firing?

The reason for the questions is the chamber of a rifle can get pretty hot after firing a round and so if you put an new round in immediately after firing and let it sit for any significant amount of time, it can heat the round up to higher temperature than you think it was and/or closer to each other.

 

[swampshooter]

Thanks for posting your results. I'm going to make a cold weather test with H-4350 in my 30/06 next Monday, 1/12/15. I'll post the results here when I get them. PS I'll make sure that I shoot fast so I don't cook my rounds.

 

[dmoran]

jlow -

Instead of repeatedly questioning, contradicting, and advising peoples tests & results, like you always do, run your own test with your own set of desired parameters. Else wise, take the information for what it is and what you get from it, and call it good....

If you want scientific laboratory proven results, go get em'.... but your likely not going to find many here.
Simply because most people here are doing such test to fulfill there own desires, then share them here as is....

 

[savagedasher]

Thanks for the information. I have a hard time testing when I have to put long pants on.
Larry

 

[chkunz]

Great! Now that you have the data it seems like the next thing is do estimate what the difference in velocity that you found is worth on the target. Why not run the ballistics calculation to see what the velocity difference is worth in the trajectory and that will give you an estimate of what the velocity difference is worth on the target. Then you can decide if it is significant or not.

 

[FatBoy]

I've been shooting H4350 in six or seven 6.5x284s. We shoot year round most years and I would say the elevation difference I experience at 1000 yards is more due to the air temp,(air friction) which is to say my 1k zero averages about 2 to 2.5 MOA low when it's 35° rather than 85°-90°.

I love H4350 and Varget and would shoot these two powders in everything I own, and pretty much do.

 

[CaptainMal]

Thanks for sharing your findings.

Not sure if the results show temperature sensitivity or insensitivity. Too subjective for me. There was a change and that's real good to know.

 

[jlow]

Looks like dmoran is still mad… :

Please get over your bad feelings and move on or I will have to ask the moderator to intervene.

 

[charcher]

FTRinPA, thanks for taking the time to put that up. 8)

Kevin

 

[Syncrowave]

For the cold rounds, I placed them in my freezer for about 4 hours. Then I wrapped them in a cold pack and put them in a cooler for the trip to the range.

Just FYI, I've read in the RCBS manual and elsewhere that shooting ammo that is freezing cold can boost pressures through the roof, counterintuitively.

 

[CatShooter]

For the cold rounds, I placed them in my freezer for about 4 hours. Then I wrapped them in a cold pack and put them in a cooler for the trip to the range.

Just FYI, I've read in the RCBS manual and elsewhere that shooting ammo that is freezing cold can boost pressures through the roof, counterintuitively.

BS on RCBS!!!

I have shot frozen ammo with no problems... but it ain't just me. Every year, deer hunters shoot frozen ammo with no problems.

During WW-2, hundreds of thousands of USA guys, Russian guys, and German guys shot millions and millions of rounds of frozen ammo with no problems - when you read stuff like that, don't forget to turn on your common sense.

Gun powder is not a liquid, so it doesn't freeze.

 

[jlow]

Catshooter is right that shooting freezing cold ammo is not a problem.

However, under certain unusual conditions, it can be a problem. That condition is akin to what the OP is doing which is chilling ammo and using it in warmer temperature. The reason is the chilled ammo will have moisture condensed on its surface much like what happens when we take a cold can of beer out of a fridge. The moisture on the surface of the case acts like lube and prevents the case from grapping the chamber when the round is fired and this cause all the force from the firing to be directed at the bolt causing what is called a dangerous bolt thrust. You are probably safe with a modern gun but older guns are at risk. What is also affected is the case head which can experience undue pressure resulting in case head expansion and pressure signs.

 

[CatShooter]

Catshooter is right that shooting freezing cold ammo is not a problem.

However, under certain unusual conditions, it can be a problem. That condition is akin to what the OP is doing which is chilling ammo and using it in warmer temperature. The reason is the chilled ammo will have moisture condensed on its surface much like what happens when we take a cold can of beer out of a fridge. The moisture on the surface of the case acts like lube and prevents the case from grapping the chamber when the round is fired and this cause all the force from the firing to be directed at the bolt causing what is called a dangerous bolt thrust. You are probably safe with a modern gun but older guns are at risk. What is also affected is the case head which can experience undue pressure resulting in case head expansion and pressure signs.

Logic inventory check...

1 - That a thin ring of brass that is less than 1mm thick, can protect TWO 1/2" x 1/2" lugs made of hardened, ordinance steel?

2 - That the head of a fired and reloaded case that is a perfect fit to a chamber (maybe a few thou tight), with a bullet seated to a 20 thou jam... somehow does not touch the bolt face.

3 - That the 3,000 to 5,000 pounds of force against the bolt face, which is rated at 100,000 working pounds (REAL pounds, NOT PSI) is somehow dangerous..

Please 'splain???

Inquiring minds want to know...

 

[Alex Wheeler]

I agree, the lugs are more than strong enough to handle the bolt thrust. Some guys lube their cases to help fire forming.

 

[flatlander]

Layne Simpson recently did a similar temp test with IMR's new 7977 powder - you can read about it starting on pg 27 in the new Hodgdon 2015 load manual/magazine. IMR is claiming its new Enduron line of rifle powders (4166, 4451,7977) are less sensitive to temp changes, and it would appear from Layne's testing that at least 7977 is fairly stable in wide ranging temps, though perhaps not as stable as the Hodgdon Extreme series of powders. Still, not bad for double base powders, plus they have an ingredient that's supposed to reduce copper fouling.

I used WW452AA shotgun powder in nearly all my 45ACP handloads when I was still shooting the 45 in IPSC matches back in the '80s. While attending the '87 USPSA Nationals at Berry, Ill., the temps on several days never got above 45*F. Some of the Texas shooters were dismayed when their 45 loads using W231 failed to make the major power factor in those cold temps, while my WW452AA loads were going 25-40fps faster than they had on warm days when chrono'd at home. I've heard that a few other powders that are not supposed to be sensitive to hot temps will also exhibit this 'reverse' sensitivity - IIRC, Varget was one that was mentioned. Anyone have any experience to either back this up or refute it?

 

[jlow]

Like I said “You are probably safe with a modern gun but older guns are at risk. “ More to answer the pose question than to sound an alarm...