H1000 at Cold Temps


December 9, 2010, 09:33 AM
Has anyone had problems with H1000 at cold temps? Worked up loads at approx. 70 deg for 7mm RM and 300WM. Both at near max charge. Some friends took these loads hunting at approx. 10 to 15 deg. and reported what seemed to be extream low pressure (low recoil, somewhat quite, smoke).

I've disassembled many of the same batch and have found consistant charges and no other appearent defects. I plan to fire some of same batch this weekend at our current temps (+/- 30 deg). I am thinking about freezing some of the ammo to approx 10 deg and test firing. Does anyone think freezing ammo to 10 deg and firing in a rifle that is 30 deg will be a problem?

7mm RM
Win Large Mag Primer
H1000 Powder 69.4 gr
140 gr Game King

300 WM
Win Large Mag Primer
H1000 Powder 83.8 gr
165 gr BT

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December 9, 2010, 10:42 AM
One thing I didn't mention, loads worked up in GA (approx 75% humidity) and friends fire in KS (much dryer). I'm at 1,130 ft ASL. I have not researched KS elevation.

Somebody Give Me Some Love!

December 9, 2010, 10:55 AM
I don't use H1000 myself, but it is an Extreme Powder by Hodgdon's standards. And a quote from them: "Our exclusive line of extruded rifle powders – Hodgdon Extreme™ – was developed to give shooters consistent performance, load after load, in even the most extreme heat and cold.".

Certain conditions can exist for that statement to not be exactly true.

Not using it myself puts me at a disadvantage, but my reloading experience allows me to comment.

H1000 is one of those powders that works best with the heaviest bullets per caliber. A 160-175gr bullet in 7mm Remag will allow the very slow powders to develop more consistent pressure curve.
Both calibers would benefit from heavier bullets with that powder, or a faster burning powder with the selected weights.

Hopefully your friends tested their equipment before hunting.


December 9, 2010, 11:09 AM
Thanks for the imput. Friends tested in GA, then traveled several hundred miles to very different conditions without testing in local hunting conditions.

December 9, 2010, 01:05 PM
I use 1000 in 338-378 and have not noticed the difference from the heat of summer to late BG seasons here in CO.

December 9, 2010, 01:37 PM
Thanks for theinfo x-rap. I'm going to do a little testing and will post if I come up with anything interesting. If I freeze any ammo and test at specific temps, I'll pass that along.

At this point, I'm kinda leaning toward the diference in air density between GA and KS. This would not create a big difference in velocity/preasure (?), but might make a difference in report. I'm keeping in mind my friends statement about very little recoil, but I don't remember ever feeling much recoil after sending one downrange at a trophy deer.

Not related, but I just found this site yesterday and it's great! Thank you!

December 9, 2010, 02:31 PM
Like NCSmitty, i dont use H1000, but he is correct. All you need to do is go to the hodgdon website. Look at the 300 win. mag. data only using H1000. Note with lighter bullets with the case filled to compressed (C), the pressure CUP is not up to where it should be. Both your guns are hanging near the lower pressure areas. If using a different bullet with less bearing surface contacting the barrel, you will have even less pressure. :)

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