Agree, harder than needed.
Then again, pure wheel weights are harder than needed.
If you get any leading, give them a very LIGHT tumble lube in Lee Liquid Alox or 45/45/10, and order 0.001" larger bullet next time.
For softer (12-15 BHN), you can go to mastercastbullets.com, Missouri Bullets, or Penn Bullets.
Alternatively, you can go to coated bullets (my favorite are Precision Bullet's Black Bullets that are swaged for uniform weight and dimension).