zhughes Can you do $15 for a good testing method? Here is a video that demonstrates using various high quality lead pencils with a scratching method to determine lead hardness very well. Get the pencil set at an art store or on Amazon. It works excellently and is CHEAP. Study the method in the fun video and you are set. Video:
I have done this method and have a Lee hardness test kit also. Both methods agree very closely.
Hardness does matter a lot! use the method in the Lee book, Modern Reloading Second Edition, to determine lead hardness needed for your load level and you won't go wrong.
Personally, I use a BHN15-16 recreational alloy from 1:1 Jacketed bullet scrap : Linotype Scrap or commercial certified Lyman #2 alloy or Commercial certified Hardball Pistol Alloy, all air cooled only and the lowest level load that will cycle my action reliably with AA2230 or H4895. My bore is polished and I have zero leading. Actually bullet fit is more important than hardness to eliminate leading. That is a lot harder to learn if you are new at shooting cast bullets in an AR.
Your drop quenching significantly raises BHN beyond needed for an AR. Bullets too hard OR too soft are more critical to fit and reduce accuracy potential. If your bullets fit with an ink test slide fit on chambering then that excellent fit gives more leeway in bullet hardness. If you don't get the correct fit then problems are magnified. I use the Lyman #225646 mold and gas check/size at .225 for an ink test fit for my AR, it shoots >1.5 MOA with cast consistently and it slams competition steel silhouettes down easily at 100 yards. I tumble lube 45:45:10 once lightly before size/check and twice lightly after.