Home Forums Hunting & Shooting Ask The Gunwriters How are Vihtavuori Powders for Temp Sensitivity?

I have started using some of their rifle powders and was wondering if anyone has any input on their temperature sensitivity.

When the N500 series started being imported it was billed as temp tolerant. I used quite a bit of it. I was trying to find an equivalent to RL22, around the N560. Ended up that N160 was better for tolerance for me and I used it quite a bit in a 338 Win Mag with 225's. It still lost velocity in extreme cold but not quite as much as RL22 in my guns. Found the same to be true with the propellants suitable to the '08 chamberings using N540-50 versus N140-50. Those powders worked great in 7-08's. Didn't check them in extreme cold but I concluded the double based N500 series was not my cup of tea.

N560 is one of the ones I am using.
Why is the 500 series not your cup of tea? because of the temp sesitivity?

V133 is the most popular BR powder. It is temp & humidity sensitive. We have excellent powder throwers and throw straight without weighing. The guys that did best knew when to go up or down with temp and humidity changes. The powder throwers are very accurate but throw volume and not weight. For BR and we are very anal, if you weigh ea. load you will be on top of it. The volume changes with temp and humidity.

At the time I was developing loads in our warm weather for use in late season hunts November and December in Wyoming and Montana. When I chronographed those powders in sub freezing temps they lost significant velocity. N160 was better than N560. I had just not gotten around to the Hodgdon Extreme line at that time, where I finally ended up using H4831, which turned out to be the most tolerant of extreme temp variande for me. It was just a matter of choice. In fact, it made very little difference for shots in normal hunting range under 3-400 yards. Made one shot and hit exactly where I was aiming, @ 175 yards after I had just chronographed a load with RL22 that was 200 fps slower in the cold than when I had developed it. Didn't make a bit of difference in the end.