Originally Posted by Brentster7189
But with these various powders like IMR, Varget, RL15, RL17, etc. I'm wanting to just know in lamen terms what the difference is between these that a beginner like myself would understand.
size & shape of the granules that affects metering and fill capacity
burn characteristics such as temperature sensitivity, how clean, and burn rate which affects the pressure curve and peak pressure developed for a given load
ideally, you're looking for a powder that gives a decent fill ratio and burns nearly completely within the length of your barrel giving the bullet the required muzzle velocity within the pressure limits of your cartridge
people choose powders with different priorities (a) low cost, (b) what's on hand, (c) best accuracy, (d) max velocity, etc...
your loading manual will often bold or have a star by a powder/load that produced the most accurate group(s) in a given test rifle
you can get lots of good suggestions on the internet, but NEVER trust those without double checking with an authoritative source such as a published loading manual or manufacturer's website and working up your load safely for your rifle
be safe and have fun!