Retumbo Powder

Has anyone noticed that retumbo is sensitive to cold vs warm weather? I got my pet load out for my rifle which is a 30-378 which I shoot 210 vlds over 103gr of retumbo. Usually, in the summer, is about a 1/2" group at 100. If you go to hodgdon website it says 101-107 for 220s (they dont have anything for 210)I have had the gun for 2 years but never shot it when it was cold. So today, I went to shoot my pet load for a winter elk hunt and I had to beat the bolt open with a hammer. Anyone else notice if retumbo is heat sensitive?

If you had pressure problems shooting it in cold weather seems it has cold sensitivity. The only answer I can think of is slow detonation and partial burn caused pressure buildup? The same thing can happen when you load a powder below recommended starting levels. Would call Hodgdon and ask.

I get delay fire if I use anything but a mag primer. For example if I use BR2 primers, you can hear 2 explosions happen. You hear the primer and then the powder. But I move to the mag primer that goes away. The 103 grains of powder is low end but it is within range. Just looking for anyone that can confirm it and it being sensitive to heat

All the Hodgdon extreme powders are somewhat temperature sensitive....if you read "the fine print" Hodgdon says they are "less sensitive" to temperature extremes than their regular powders. Why not go with a powder that is a bit faster like H1000?

Well I am thinking that it is going to turn out that it is a problem with the throat. I have to seat the bullets so far down in the case in order to fit them in the chamber. Even the temperature sensitive powder that I have seen doesn't have that much change. The loads I tried are 1gr over starting and 2 grains over the starting loads according to Hodgdons website. The max according to hodgdon is still 5 grains away. I made sure the scale was on, and the max load is a compressed load and I am not where near that. I also only get 2 shots per case, and at $3 a case, this is to expensive to shoot without getting it fixed, let alone when it decides to blow my face off. I am thinking I am going to send it out and have it throated for the new 230gr berger hybrids and have the smith take a look at it while its there.

I find the Hodgdon Extreme powders to be VERY forgiving in temperature variances. I work up my loads in the 90F and humid days and shoot almost year round....including when it is 15 below in the middle of Nebraska.