Thread: Vihtavuori n560 temp sensitivity

Anyone on here had much experience with this powder? Seems it might be fairly temp sensitive.
Did all my load development back in winter for my 280ai. Using 135gn CE er raptor pills with 61.5gn of 560. Cutting edge gave me data listing my max load at 63.4gns so I'm well below that. Didn't see any pressure signs at all back when testing at about 5-10 degree weather. Now that it's warmed up I'm popping primers clean out and leaving slight ejector marks. Accuracy is still the same. Haven't put it through the chrony again yet but thinking I should just back way off and start again? Or change powder?
TIA

Sent from my F8331 using Tapatalk

Have a look on "longrange hunting.com", you may get some info there... Seem to recall there was a discussion on vv570 temp stability.

Originally Posted by Jpayne

Anyone on here had much experience with this powder? Seems it might be fairly temp sensitive.
Did all my load development back in winter for my 280ai. Using 135gn CE er raptor pills with 61.5gn of 560. Cutting edge gave me data listing my max load at 63.4gns so I'm well below that. Didn't see any pressure signs at all back when testing at about 5-10 degree weather. Now that it's warmed up I'm popping primers clean out and leaving slight ejector marks. Accuracy is still the same. Haven't put it through the chrony again yet but thinking I should just back way off and start again? Or change powder?
TIA

Sent from my F8331 using Tapatalk

I have used it a fair bit in a short and long action.
You will generally get some change in pressure/velocity with any powder in my experience thru a change of seasons.

If anything I have noticed with N560 is that it will spike at some point around the max load for your barrel. (You will get a big shift in velocity for a minute change in powder charge)
I don't think it is temperature sensitive enough to worry about for most NZ hunting conditions. We just don't get the extremes they do overseas.

I try not to do load development in the winter unless I have a standard ISA day.
(15° 1013 mb at sea level)

If I have to develop a load in winter and I am at or near max I always back it off between half and a full grain and re confirm it in summer as accuracy is generally sorted.

I dont use my larger caliber rifles for hunting in the summer anymore so I don't really have an issue but what is a safe load in the summer will be safe in the winter generally.



Sent from my SM-G935F using Tapatalk

I used it in my 270win for a while and never noticed anything unusual. Not a particularly hot load though.

Ive used it forever in my 6.5x55 right on the cusp of max. Never had a problem. I have noticed that if you change case brand you need to make slight adjustments - but thats not unusual with any powder and case changes.