Do you measure your powder by weight or volume?
I use pre measured powder holders and use 73gr Blackhorn 209 which is about 110 gr by volume. I find it is much more consistent shot to shot this way as volume can vary greatly IMHO..

I weight my BH 209 powder 75grs., more consistent groups.

Seems to me that with BH209 weight would work best. Most, if not all other BP subs absorb much more moisture and cannot be weighed effectively.

Absolutely nothing wrong with weighing Blackhorn powder. However, my loads i always measure by volume.

110g of Blackhorn is supposed to weigh 77g, so it would seem a weight of 73g would result in a light 110g load. One thing i have noticed, is different lots of Blackhorn do have different densities. When switching to a new container, one may find that the weight-volume ratio changes. It may be one needs to re-establish one's load when opening a new container with a different lot number.

One nice thing about Blackhorn is the size of each granule is very very consistent. This lends itself to accurate measuring by volume. Seems it also lends itself to accurate measuring by weight...

I've never weighed my charges and always measured by volume. But it would seem logical that measuring by weight would give you more consistent results.
I am surprised about the fact that BH209 has different densities from lot to lot as Ron stated. How much that would affect your accuracy - who knows.

I have done both. And to be honest, found very little difference in accuracy between a weighed charge and a volume measured charge. But let me add, I don't shoot long distances. So the distances I normally shoot, a slight variation in powder charge would have little to no effect. If that were stretched out ten fold, I am sure that some notice in accuracy could and probably would be noted.

I've shot and used BH209 since it became available and at ranges from 100yds to 400yds. I've always shot it by weight, using the conversion provided by Western (.7). Shooting by weight, I've never experienced any differences from one container to another of my POI. My normal charge from production rifles was 75grs by weight, which using the conversion number provided by Western equals 107.1grs volume. In the Ultimate, I shot 100grs by weight (NOT for production rifles), again no change from bottle to bottle in POI. However....... shooting heavy charges from a custom barrel, BH does require swabbing every 3rd shot to maintain long range groups.

Volume shoots consistent groups for me.

Took the words right out of my mouth. I haven't found an advantage to weighing charges.

I don't shoot BH209, but I've always just used volume. While I don't shoot nearly as much as some of you, my groups have always seemed to be very consistent. I try to be consistent with my method of volume measuring so that hopefully my loads are close.