A little WD40 will help a lot if coolant is not an option. Something is a must (as you are figuring out).yep its just 6061.
tried to increase it to 4000 and just destroyed it even faster on the first step down.
its a bright polished end mill and 45 degree helix and sharp corner, might switch to a 0.030rad if i can.
had it plunge at first, ya got about half way, clogged up and snapped it off in the holder.
You have to keep the tool wet with something that has at least a little lubricity.
You can even mix up some coolant, and put it in a squirt bottle. Then stand there and keep spraying.
It will make all the difference in the world. To the point that your cutting parameters really don't even matter.