H4350 temperature sensitivity test

[Jdne5b]

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?

I have not seen Varget be reverse sensitive. Pistol/Shotgun powders WST and WSF are reverse sensitive. WW452AA was replaced with WST, but I'm not sure if they are the same powder.

 

[Joe Salt]

Z I don't think I would try that! The thing I see all the time that isn't good is the rounds that have moisture on the outside when they take them out of a coller. You better make sure you wipe them off good before shooting. The water will dent your cases. The other thing is when my rifles sit in my gun trailer over night and its cold, the loaded rounds stay with me and there warm. So when you have a cold gun and warm brass I always have to shoot more sighters to get the rifle warmed up. Just another Observation!

Joe Salt

 

[jlow]

Joe, you are right on there. I still remember my precision rifle instructor Ed Shell telling me about his bad experience shooting rounds that got wet in matches and how they could not be used afterwards for reloading.

It is no stretch of imagination to say that reloaders should remove lube on the case from FLR before firing for the same reason. Can one get away with it? Maybe.. But should one do it? The answer is clearly no and I certainly hope no one on this board would suggest that this is a good safe practice.

 

[savagedasher]

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...

The hardness of heat treated stainless 17-4ph rock wells36-38 which many actions are made if.
4140 steel has 44 -45 hardness
Lugs aren't made from hardened ordinance steel Larry

 

[Frankr]

FTRinPA I have seen the test you did conducted several times. the results are good. as you had. BUT
If you are in PA you will not have a problem testing it under actual temp condition. I have tested H4350 in my 6XC at actual 85 deg F then at actual 25 deg F ...85 deg F 3,050 FPS....25 deg F 2,950 FPS...so under actual outside temp conditions , actual shooting conditions it does not work..actually I have seen 50 FPS swings with as little as 20 deg F outside temp change..I know a few other shooters have had to make adjustments form 60 deg F in the morning to 80 deg F in the afternoon...I would like to see some one else test it under actual outside temp conditions..actually is that not where it is important? no way my ammo is going to freeze on a 70 deg day..Right now it is 21 deg F ...and will not be warm for several months...But if you have a know velocity at 70 deg F go out and shoot it a 21 deg F and see what the velocity is.. I would like to known what others find out, because what I have found is not good..

I have found very few powders that work form 80 deg F to 25 deg F..you will loose velocity when it gets colder..it just a matter of how much you loose...so far RL17 has been the best I have ever tested...6.5 creedmoor,6XC..
has form -10 deg F to 90 deg F around 75 FPS ..that is the best I have ever seen...I hear guys say all the time ah this is extreme powder, its temp stable so I don't have to worry about it...I just laugh...GO OUT and test it under actual outside temp conditions and let me know what you find out..

 

[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...

The hardness of heat treated stainless 17-4ph rock wells36-38 which many actions are made if.
4140 steel has 44 -45 hardness
Lugs aren't made from hardened ordinance steel Larry

Larry...

I did not make that up - those numbers came directly from Richard Diaz - Head of Engineering at Remington, in GA, and he stated that those figures were applicable to Remington and Winchester two piece bolts, where the heads are hardened ordinance steel, welded to the bolt body - they do NOT apply to one piece bolts.

 

[jlow]

I too am pretty interested in the temperature sensitivity of powders for the same reason. I wonder if anyone has done actual testing and compared the change in MV to what QuickLoad predicts for the same powder in terms of actual change in MV as a result of temperature change?

 

[dkhunt14]

I too am pretty interested in the temperature sensitivity of powders for the same reason. I wonder if anyone has done actual testing and compared the change in MV to what QuickLoad predicts for the same powder in terms of actual change in MV as a result of temperature change?

I would think that you couldn't prove it because of the variances of barrels, powder burn rate within a lot, diameter of bullets and throating in a gun. Quickload cannot control these variables to a degree where it could be proven. Matt

 

[dmoran]

I would think that you couldn't prove it because of the variances of barrels, powder burn rate within a lot, diameter of bullets and throating in a gun. Quickload cannot control these variables to a degree where it could be proven. Matt

+1.......
Also it's obvious to me how a well tuned load is less sensitive to ambients.
Donovan

 

[jlow]

I too am pretty interested in the temperature sensitivity of powders for the same reason. I wonder if anyone has done actual testing and compared the change in MV to what QuickLoad predicts for the same powder in terms of actual change in MV as a result of temperature change?

I would think that you couldn't prove it because of the variances of barrels, powder burn rate within a lot, diameter of bullets and throating in a gun. Quickload cannot control these variables to a degree where it could be proven. Matt

Generally agreed, but just hoping.... ;D

I think we all know that you got to tune QL for your rifle that accounts for all of the above and more, so there is no real possibility of getting true accurate values that match the actual MV. The question though is even if the actual MVs are off, would the relative change in MV between temperature be accurate? This is where I was coming from.

Regardless, I will find out this year as I finally have my QL tuned and been shooting out in the cold temps. When summer comes, it will be interesting to see if the predicted MVs still match.

 

[LHSmith]

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.

Not necessarily . Solely dependent upon the relative humidity of the air the chilled ammo is exposed to.

 

[jlow]

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.

Not necessarily . Solely dependent upon the relative humidity of the air the chilled ammo is exposed to.

Yes agreed. Not only that, it depends on the relative difference in temperature. It's only a possibility and not a sure thing but a reasonable possibility.

 

[Syncrowave]

BS on RCBS!!!

Well, once again, I guess RCBS/CCI and Sierra and Hodgdon and IMR and all the rest are wrong, and CatShooter is right!


Why is that not surprising?

 

[Eddie Harren]

Hee, Hee! "Here Kitty, Kitty, Kitty."

 

[CatShooter]

BS on RCBS!!!

Well, once again, I guess RCBS/CCI and Sierra and Hodgdon and IMR and all the rest are wrong, and CatShooter is right!


Why is that not surprising?

Wassa matter syncro.. get your weenie caught in the screen door (along with eddie and his buddie who makes sniper ammo for the fbi in his basement)...

First, I said nothing about CCI and Sierra and Hodgdon and IMR and all the rest...

Second, if freezing ammo... "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."

Then explain how hunters can hunt in 20 below temperatures without their guns blowing up, and why there are no warnings on ammunition boxes (in an industry that is totally paranoid about safety and law suits) warning of dangerous pressures when used below freezing...

... and explain how we fight wars in frozen countries like Korea (Can you spell "Chosin Reservoir"), and Germany and our guns don't blow up when the pressures go "... through the roof"..

Explain how aircraft shoot at each other at 30,000 feet, where the temperature is minus 50° to minus 70° below zero and EVERYTHING is frozen solid. Are the guns blowing up because the pressures go "... through the roof"??... or I guess "through the wings" would be more appropriate)

So... if RCBS is not full of BS, then that leaves only one other source of such garbage - so syncro, please quote the source of this junk in your RCBS literature... cuz if RCBS didn't say it, then I am beginning to think you are the one who is BS!

Hee hee hee...

 

[dkhunt14]

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.

I don't believe its the freezing temperature but the moisture that forms on the case from going cold to hot. Two years ago in the World open it was drizzling, more like a heavy mist. There also was a slight breeze blowing toward the benches. I was not shooting a hot load either. During the sighter period I could use my arm to shield my shells sitting in a block. Once the record started the shells got wet. As I shot the string of 10 shots bolt lift and pressure went up. By the time I got to shot 10 the bolt was almost impossible to open. I believe the moisture drove the pressure up. I measured the fired cases and case expansion on shot 10 was a couple of thousandths bigger then shot one. The next day the same loads were fine but the day before it destroyed my brass. The same thing happened to another guy that day and he asked me what I thought caused it. I said I believe it had to be the moisture. He said his cases were the same way and measured the same as mine. Matt

 

[Eddie Harren]

CS, "eddie and his buddy who make ammo for the FBI in his basement...". Wrong organization and wrong info. You will never know the truth.