How to select a powder?
 

If limited to buying several powders how do you decide which powder would be the best one for you? Do you go by what powder gives you the highest velocity, or by the least amount of powder to give you near the highest velocity?

Greatest forgiveness and least sensitivity. Those criteria will pay off as greatest precision more reliably.

Please explain this. I've been loading for over 55 years now and I'm not sure what this means.
I normally selected a powder that would fill the case to the bottom of the neck with the max charge and give me the highest velocity. This would allow me a wider range from starting load to max load to work with. I always liked using as much case capacity as possible.

I'm just curious how one decides on which powder to choose from looking at the reloading manuals as to which one may provide you with the best accuracy? Granted each rifle is different, but there must be some way to decide on one or two powders?

ID suggest you buy and read this reload manual, its by far the best Ive found and I own over a dozen
as it gives a wealth of info like that

A lot of powders will offer a high fill ratio at maximum charge weight - or rather, achieve the cartridge max pressure standard at a high fill ratio. But not all powders will remain reliable and consistent across varying environmental conditions. For example, H335 is great in 223rem, but is exceptionally sensitive to temperature, so what load I develop in an indoor range may end up spiking in the heat of summer, and push me out of a node. Alternatively, Varget is exceptionally temperature insensitive. So any time I can align cartridge case capacity with Varget, 8208, Retumbo, or H4350, I use those over some other powders. For example, Leverevolution is very temp stable, as is Superperformance, so even though LR gives higher velocity in 243LBC and 6 ARC than 8208, I choose 8208 instead because it is more reliable, making it more predictable, and easier to load to shoot smaller than LR. 4064 is less sensitive than W748, so 4064 gets the nod for my 30-06.

Equally, some powders tend to offer wide nodes - great forgiveness - so choosing H4350 makes more sense and shoots smaller for me than RL17.

Eliminating, or reducing sensitivities decreases variability, and decreasing variability inherently increases consistency, and subsequently precision.

So by eliminating powders that are not temperature sensitive, do you go by what powder gives you the highest velocity, or by the least amount of powder to give you near the highest velocity in selecting a powder?

OK I understand what you're saying Nomercy but manuals don't tell you what powders are temperature sensitive. At least not the ones I have. Where do you get that knowledge?

I don’t really care too much if a powder uses 30grn or 35, and honestly, I rarely worry too much about achieving maximum velocity - even shooting long range, speed is nice, but it’s not everything, and the difference 50-100fps makes between one powder and the next doesn’t tend to matter to me as much as forgiveness of a load. A specific example of this - Leverevolution will handily outrun 8208 in 243 LBC (6 Grendel) or 6 ARC, but it’s far more temp sensitive, so I use 8208 and shoot smaller groups.

There are a lot of resources which discuss temperature sensitivity, or insensitivity, of various powders - even some tables out there referencing specific fps/degree changes. Hodgdon uses the “Extreme” line to denote their temp stable powders, and uses the “Enduron” line label for their IMR temp stabilized powders. Online forums like this are great resources as well. Temp sensitivity isn’t the only piece of the puzzle, naturally, as I mentioned, chargeweight forgiveness nodes will vary for different powders, and for different cartridges. Some powders promote big, wide nodes for almost any cartridge, while others seem to never offer well defined nodes at all - I choose the former, which for MOST cartridges I shoot lands me between Varget, 8208, H4350, or Retumbo.

So again looking at the various powders for a selected cartridge in a reloading manual, how does one decide on which powder will/should give you the best accuracy ?