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

 
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  #15  
Old 10-10-2010, 12:20 PM
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Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Thanks for all the good comments.

Can anyone quantify an answer from their own experiences?

Powder used __________

Temp difference __________

Velocity average difference ________
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  #16  
Old 10-10-2010, 12:23 PM
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Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Quote:
Originally Posted by RockZ View Post
the press release link provides temperature and velocity data
Oh, well that must make it true then...

Look, I applaud actual efforts toward temperature stability in powders. I like Hodgdon powders.
I just haven't seen any efforts beyond baseless brochure claims. And if there were any actual basis, I think they would lay it all out for us.

Our shadetree testing has produced nothing more than abstract results. Someone says VV powders seem stable. I found them to be the least. The US869 brochure claims linked were just countered by someone here who tried it. What does it mean? NOTHING.
Standard velocity drops per temperature have held up well with my Hodgdon powders and loads, and I'm glad for that. But the least temp sensitive powder I run right now is IMR4350, and I'm not seeing alot of hype with IMR. Why did Hodgdon buy them?
I've seen Hodgdon discontinue an extremely popular powder without a replacement in the past, only to bring it back later. What are they planning to do with IMR?

I don't trust hodgdon, or their claims. I see them playing on a placebo effect among this hurd, as we believe what we WANT.
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  #17  
Old 10-10-2010, 03:04 PM
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Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Quote:
Originally Posted by XWrangler View Post
I did my own non-scientific test a couple of months ago with some powders.
The temperature was in the upper 80s to lower 90s and I ran my loads thru the chronograph. I then took 5 of each of the same loads that I had in a cooler with dry ice. These had been in my freezer for a couple of hours at home before I went to the range with them in the cooler. I pulled them out one at a time and shot them through the chronograph and my Retumbo loads were the hands down winner. These loads were in my 6.5X284. I had loads with Accurate Magpro, Hybrid 100V, Viihtavouri N 165 and Reloader 17. Surprisingly the Reloader 17 was the second place winner. I was just going by accuracy at 200 yards and extreme spread of the speeds. The Retumbo was 9 fps extreme spread with warm temp loads and 11 with cold loads. The Reloader 17 was 13 warm and 17 cold. All of these loads had shot good groups in the gun so they were the ones I selected for the test. It was kinda fun to see the differences. I did this over a weeks time so I know there is some variation in outside temp but overall it was pretty close. If anyone else has ever tried the freezer test I would be interested to find out your results. I am always looking for a excuse to burn more powder and lead!!!
I find the RL-17 coming in second very surprising! I bought an 8 lb. can of Rl-17 for my 300 sherman because when I tested it a couple of months ago I got very good velocity and accuracy. When I got ready to tune up for elk season, I started shooting in colder weather and found that velocity dropped WAY off as the temp went down. I was so disappointed that I've temporarily switched to IMR 4831 which showed more consistency. I have had good results with retumbo when I've used it in magnum cases and even in my 6.5 Sherman but it is too slow for my 300........Rich
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  #18  
Old 10-10-2010, 07:34 PM
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Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Here is some data for both RL19 and IMR4350 out of a 338 WM shooting 225 Accubonds and CCI250's. One was a cold morning and the other was mid-day in the sun.

73 gr of IMR4350

37F, Avg velocity was 2921 fps
68F, Avg velocity was 2992 fps

76 grains of RL19

37F, Avg velocity was 2902 fps
68F, Avg velocity was 2961 fps

Because of these swings, I think I am going to try H4381sc in hopes of better temp stability. I didn't think they were this temp sensitive.
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  #19  
Old 10-10-2010, 07:57 PM
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Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Good info.
What's difficult about temp testing, and possibly why the results are such an abstract, is seperating cold primer performance, from cold powder.
Then there is bore dimension changes(if it was at the spread temps). Firing pin strike at spread temps.
There is air density diffs in the bore, and for all we know, a cold bullet might be a factor..

So even if our powders perform as claimed, we will not likely see it.
I never have.
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  #20  
Old 10-10-2010, 09:03 PM
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Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

At a recent field course held by www.longrangehunting.com.au here in Oz, it was revealed that 2209 (sold in the US as H4350) loaded into a .303B gave a 1.514fps velocity increase for every degree increase in temperature from 0.c (freezing) to 35.c (95 Fahrenheit).

Norma Factory Ammo ( Vihtavouri ?? ) gave appox 3.5fps increase per degree of temperature increase.

Ammunition was fired over a chronograph and was held at freezing and a second lot warmed to 35 deg C. I beleive this helps the long range shooter determine the actual burning rate of the powder in his load, in his rifle.
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  #21  
Old 10-10-2010, 10:16 PM
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Re: Hodgdon's "Extreme Powder" - reduce velocity variations due to temperature chan

Sounds like a good area for someone to do a LOT more testing! I've been keeping rounds in my pocket next to my body until I'm ready to shoot in cold weather. Even at that, there are still all the other factors mentioned by Mikecr. Maybe given the extreme ranges we are shooting, we could fire two or three shots into the ground without scaring the animal in the process and then chamber a round, let it sit in the warm chamber for 30 seconds, and THEN shoot at the animal
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