The type of powder and the type of measure as well as your methodology.
I like APP FF because I can use a volume mease and it keeps the same groups.With FFF I have to weigh with Black powder or Pryodex volume works well for me but with Gold or pinnicle I have to weigh. Lee

Just browsing andfound this thread...had an interesting thought:

"I wonder how many peoplecould tellif someoneloaded their rifle behind their back and short charged their pet hunting load by 5 grains volume?"

5 gr by volume may not seem like a lot but would probably result in a flyer.

Actually flyers wouldn't show from that...you couldbet money on every shotthat theshooter couldn't tell you (from knowledge, not guessing) which shot was the full charge and which shot was 5 grns less...if a 5grn reduction could be determined at all, it would simply be that it printed an eyelash lower...black powder and subs are not that precise, not that sensitive...smokeless powder of course would show adifferencebut a 5grn volume fluctuation with BP would go unnoticed...that's really whythe volume measurement system doesn'tdetract from accuracy

I personally think that if a person wants to measure their loads, what's the problem? If they want to do that and feel it produces better groups for them then by all means do it. For those that think it is not necessary, well no one is asking you to measure.

I think this calls for some field testing on my part. I will measure out ten charges and shoot a group with a roundball rifle. I will then clean the rifle and do the same with a volume charge measure and see if there is a difference. I personally think that when you keep each shot as close to the next by all indications your accuracy should improve.

Now to decide what rifle to use... May add one more extreme to this and use pellets, measured loose powder, and volume measure powder..

5 gr of 777 is enough to tell. 777 has more in common with smokeless than it does with blackpowder. The difference between volume charges and weighed charges with it is very noticable. That difference increases the further the range. I've had loads measured out volumetrically that didn't meet my minimum accuracy requirements (2"@100 yds) that the same charge weighedto within 1/10th gr easily did. I've seen weighed charges 1/2 group size. When I weighed out 100 gr charges I found differences of 2-4 gr by weight. Some of my powdermeasures were more accurate than others.

I used to know a fellow over on the old CVA forum, underclocked will probably remember him, who weighed everything, bullets, primers, powder and sabots. He grouped them with no more than 1/10th gr differences. He routinely shot 1/2" groups and often 1/4". What always got me was he was so humble about it. I wonder whatever happened to him.