Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature changes

[elkaholic]

Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

I didn't record my results but it seems like I have maybe 50 FPS difference between40 degrees and 80 degrees.

Whatever the number, it was huge.

Thanks Len! That is exactly what I found as well. It's good to get get some similar data because you never know for sure whether it's the Chrono day or ??? until it's duplicated.......Rich

 

[RockZ]

Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

I contacted Hodgdon and here is how they test the powders:

" Hot/Cold Tests:



We loaded three sets of identical information. One set went into an environmental chamber set at zero degrees F. One set went into an environmental chamber set at 72 degrees F and the last set went into an environmental chamber set at 125 degrees F. All ammo was allowed to soak for 24 hours to insure that all ammunition was uniformly heated or cooled to the desired temperature.



The ammunition was fired through a SAAMI standard, calibrated and referenced test barrel with appropriate calibrated piezo electric force transducer and Oehler System 83 Ballistic System. Each round was removed from its' environmental chamber, loaded into the test barrel following SAAMI guidelines for ammo handling and fired. The System 83 recoded velocity and pressure for each round and complied the statistical report when all shots were fired.



This is the industry standard method of conducting hot/cold tests."



Mike Daly

Customer Satisfaction Manager

The Hodgdon Family of Fine Propellants

Hodgdon Smokeless Powders

Winchester Legendary Propellants

IMR Propellants

Pyrodex

Triple Seven

 

[Pdvdh]

Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

VERY good info. This is my experience with Retumbo even though I don't have recorded numbers. Try some Reloader 17 if you get a chance........Rich

Rich,
I tried Reloader 17 in my .280 RCBS Improved. I couldn't get the ESs and SDs down to where I wanted them. Plus Re17 didn't shoot any better groups or provide any significant velocity gains over Retumbo. H1000 gave superior ES and SD and equally good accuracy. I then switched to 162 Amax's, and obtained even better accuracy and equally low ES and SDs with H1000. So H1000 is my chosen powder for my .280.

I never proceeded to the MV versus Temperature testing for Re17. Like I said, I only do the freezer test after I've settled on a good load for my rifles, and Re17 never made it to 'good load' status.

I've got 4 lbs of Re17, but haven't tried it in any other rifles/calibers. Most of my other rifles have too large of a case capacity for Re17 to shine.

 

[Boss Hoss]

Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Len----stone cold fact the H4350 data is garbage in my 6.5x284 rifles. Going from 50 to 90 degrees ambient I gained about 40 to 45 fps on my 142 SMK's but the ES were still single digits..

 

[CRNA]

Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

What about humidity?? That alone changes things. Down here you can have some pretty big humidity changes. I'll see what I have written down at home.

Isnt it the other way around? Isnt more humid air more dense, therefore the bullet drops more? Just askin'.

 

[elkaholic]

Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Thanks a lot Phorwath! I plan on trying some H1000 in my 300 Sherman with my 190's. I think it might be borderline slow (not sure if I have enough capacity) but it should be close. It will likely be a compressed load. I'm sure Retumbo would be a little slow but it does work well in my 6.5 in the same case using 140's...thanks again/Rich

 

[Mikecr]

Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Good info Code4
I've been running with ~1.8fps/deg as a default, and it's held up well for the Hpowders I'm using -in my cartridge/barrel/load combos.
And it didn't take me long to run from VV after trying it in one gun.

 

[Limbic]

Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Isnt it the other way around? Isnt more humid air more dense, therefore the bullet drops more? Just askin'.

Humid air is has more water in it. I thought I read that more moisture increase burn speed. Cold air molecules move slower and therefore you can pack more together. ie. increase in density.

 

[Pdvdh]

300 Win Mag & IMR 7828

300 Win Mag
210 Berger Hunting VLD
Federal 215 Match Primers
Powder used 73.1gr IMR 7828

Temp 1F = 2840fps - 2 shots
Temp 71F = 2909fps - 2 shots
Temp 72F = 2905fps - 2 shots

Velocity average difference: 69fps over a 71F temperature change.

300 Win Mag
210 Berger Hunting VLD
Federal 215 Match Primers
Powder used 73.3gr IMR 7828

Temp 34F = 2922fps - 1 shots
Temp 72F = 2931fps - 3 shots

Velocity average difference: 11fps over a 38F temperature change.

300 Win Mag
210 Berger Hunting VLD
Federal 215 Match Primers
Powder used 72.6gr IMR 7828

Temp 10F = 2860fps - 2 shots
Temp 18F = 2870fps - 1 shot
Temp 72F = 2881fps - 2 shots

Velocity average difference: 21fps over a 62F temperature change.

I have more data recorded with IMR 7828, but at varying powder charges. My data indicates that IMR 7828 isn't terribly temperature sensitive between 15-70F. Drop from 15F to 0F or colder, and then MV drops quickly. I continue to use IMR 7828 because my hunting temperatures are always expected to be warmer than 15F. They are generally between 40F and 75F.

 

[elkaholic]

Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Isnt it the other way around? Isnt more humid air more dense, therefore the bullet drops more? Just askin'.

Nope....more humidity, less drop..........Rich

 

[CRNA]

Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Nope....more humidity, less drop..........Rich

I'm gonna play with that on the JBM calculator and go to the extremes with humidity to see how much it changes. Not disbelieving you at all I would have guessed wrong though. Very counter-intuitive to me. I need a good physics lesson! Thanks for straightening me out.

 

[elkaholic]

Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Don't feel too bad, I thought the same thing until I ran it on JBM some time ago and did some checking......Rich

 

[str8shoot]

Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Interesting thread, funny how we can spend so much time getting our ES and SD down. This does us no good for hunting if our average velocity varies greatly with temperature changes. I had 2 loads worked up for my 7 mag, one with 68.5 gr h1000 and one with 64.6 gr rl-22. All other components and brass prep were the same. I compared these side by side on 2 different days. All 4 shot groups.

Day 1 (temperature around 40): The h-1000 load averaged 2801
The rl-22 load averaged 2809

Day 2 (temp around 60): The h-1000 load averaged 2806
The rl-22 load averaged 2861
I know this isn't too scientific of a test because I don't have the exact temperature recorded in my data (lesson learned), but I found H-1000 to be much more consistent. On day 1 they were basically the same load velocity wise but day 2 the rl-22 load would have needed slightly different drop data.
Here in MT it may be 70 degrees opening day of elk season and 10 below the next week. While I don't expect any powder to be consistent over that vast of a temperature change I'm gonna go with the one least affected. Even a 70 degree day might be 25 degrees at sunrise. That rl-22 load showed great promise with good accuracy and good ES and SD until you figure in both days, then it is not too usable for long range hunting imo.

 

[elkaholic]

Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Interesting thread, funny how we can spend so much time getting our ES and SD down. This does us no good for hunting if our average velocity varies greatly with temperature changes. I had 2 loads worked up for my 7 mag, one with 68.5 gr h1000 and one with 64.6 gr rl-22. All other components and brass prep were the same. I compared these side by side on 2 different days. All 4 shot groups.

Day 1 (temperature around 40): The h-1000 load averaged 2801
The rl-22 load averaged 2809

Day 2 (temp around 60): The h-1000 load averaged 2806
The rl-22 load averaged 2861
I know this isn't too scientific of a test because I don't have the exact temperature recorded in my data (lesson learned), but I found H-1000 to be much more consistent. On day 1 they were basically the same load velocity wise but day 2 the rl-22 load would have needed slightly different drop data.
Here in MT it may be 70 degrees opening day of elk season and 10 below the next week. While I don't expect any powder to be consistent over that vast of a temperature change I'm gonna go with the one least affected. Even a 70 degree day might be 25 degrees at sunrise. That rl-22 load showed great promise with good accuracy and good ES and SD until you figure in both days, then it is not too usable for long range hunting imo.

You hit the nail on the head with all the care we take (and don't take) I have found the same thing with basically ALL the reloader powders........Rich