Reloading .308 winch. with Vihtavuori N550 powder

[paultummers]

Hi,
I have a couple of boxes Nosler Partition 180 grain .30 caliber bullets for loading .308 Winch. ammo.
I used to load these rounds with 44.5 grain of Rottweil 903 powder and they performed outstanding.
Unfortunately I am not able to buy this powder anymore because the importer stopped.
I would like to change to Vihtavuori N 550 but have no idea about the powder charge to use to equal the performance of 44.5 grain of R 903.
Is there somebody who can give me advice?
Thank you very much!!

 

[shrpshtrjoe]

Howdy. Sorry no help on the N550 but if you have access to hodgons varget it performs very well in my 308 and loading data is on there web site

 

[rick smith]

The 3rd edition of VihtaVuori lists 37.9grs-42.6grs. of N550 for the 180gr X bullet, it is not listed with any other 180gr bullet. With the 175gr Sierra HPBT, 41.7-45.8grs. Hope that helps.Rick.

 

[Ol` Joe]

VihtaVuori doesn`t list N550 for the Nosler 180gr Partition in their #s 2 and 3 manuals, but they do list a 185gr Lapua Scenar with N550. The data shows 42.3 - 46.4 gr with a Lapua case and un-named large rifle primer @ 2.795" COL. They also have the 185 gr Lapua Forex with 39.0 - 46.0gr of N550 @ 2.732" COL. You might try working up from one of the starting loads and stop when you each the velocity you are looking for, or pressure signs appear. Which ever comes first.
You might try contacting VV for more data or down load their load data from their web site to double check for new loads. I don`t know if they have or will give any more data then they list in the manual but it never hurts to try.
BTW, you do realize R903 is closer to VV N140 in burn rate? N140 might be a better choice to get a load similar to your old one........

http://www.vihtavuori-lapua.com/

Edited to add: this data came from the #3 manual.