Vihtavouri N570 Velocity Change With Temperature

[uda123cat]

I was wondering if anyone has any data for the feet per second (fps) change per degree Fahrenheit (F) for VV N570. I have emailed VV several times and the only response I got was basically telling me that there are only two reps for VV in the US and they are extremely busy. Searching multiple forums has not been very productive other than to quote the VV marketing hype about how stable their powder is. I would like to use the fps/degree F for a ballistics program in shooting long range. At some point I will cool rounds and heat up others and find out what works for my situation and this may be useful, but may not be the same as having either cool or warm ammo shot in a similar temperature action/barrel. Any help would be greatly appreciated.

thanks
dan

 

[Chuckhunter]

I was wondering if anyone has any data for the feet per second (fps) change per degree Fahrenheit (F) for VV N570. I have emailed VV several times and the only response I got was basically telling me that there are only two reps for VV in the US and they are extremely busy. Searching multiple forums has not been very productive other than to quote the VV marketing hype about how stable their powder is. I would like to use the fps/degree F for a ballistics program in shooting long range. At some point I will cool rounds and heat up others and find out what works for my situation and this may be useful, but may not be the same as having either cool or warm ammo shot in a similar temperature action/barrel. Any help would be greatly appreciated.

thanks
dan

Approx. 2.075 fps. per degree. Since you didn't say which cartridge and bullet you were using, I used a Rem. Ultra Mag with a 165 Gr. Sierra and changed from 50" to 90" F. Remember these are only projections based on Quick Loads default settings. These could vary substantially if you entered your own personal data and adjust powder burn rate to match your actual chronographed velocities. Still, 2.075 seems a little more temp sensitive than I anticipated.

 

[Willie]

Just got in a batch of N-570 today and was wondering the same thing. I planned on trying it in a 7stw w/180 hybrids. 2 fps per degree is not good news. Hopefully, after some testing, it will have much less sensitivity.

 

[expiper]

folks need to realize the claims of the powder manufactures,,,,they are not saying that their powder will give the same vel at 100* and -20*,,,,,they are saying that it will BURN uniform at hot and cold temps,,,some older formula powders would become very UN-uniform when used in cold temps,,,,any chemical reaction will be slower/less violent at cold temps.....Roger

 

[uda123cat]

Thank you for the replies. I certainly agree with the issue of companies qualifying their comments regarding stable burn rates at various temperatures, and not that the burn rate does not vary with a change in temperature. As long as I know what the burn rate is, that is fine as it can be compensated for in an appropriate manner. To me, the ES is a much more important value with respect to precision and N570 appears to be good in that regard, or at least as good as other manufacturers. I simply wanted a value to enter into a ballistics program since I couldn't find that particular data point and VV was of no help. Of course, the less variability with temperature the better to some degree, and it does appear N570 is not as low as some powders, say Varget for example. I plan on using the N570 in a DT 375 cheytac pushing a CE 377gr bullet for ELR. Already used Retumbo with excellent results out to 2700 yds and just wanted to try a VV powder and N570 seemed to be equivalent to Retumbo according to VV but perhaps with slightly faster MV with a little lower pressure at the expense of possibly a slightly decreased barrel life.

Thanks for the input and I really appreciate the predicted burn rate for N570,
Dan

 

[Shrek]

You'll like N570. It burns more consistent than Retumbo and lot to lot is much more uniform in my experience. Smaller extreme spreads and slightly more velocity in a 300 rum. Don't have the rifle anymore and didn't keep the load info so I can't post exactly what the difference was but going off memory I lost 10fps off extreme and 4fps off standard going to N570 vs Retumbo. N570 has huge kernels and is a pita to get into a case mouth without bridging and would not throw in any powder thrower I tried. That's its only negative to me.

 

[freebird63]

I was looking at N570 for my 300 RUM. I usually have very good success with retumbo. Been also thinking about RE 26 & 33, H1000 and Magnum.
But its kinda hard to drop $47.00 a pound for N570

 

[uda123cat]

Yes, this powder can be expensive. I got a number of pounds from Powder Valley all with the same lot number for about 10.00 dollars less. They were very helpful and made sure the lot numbers all matched and shipped them out quickly. Good luck.

Dan