Don't know about them but here is one place to get them
http://www.prbullet.com/hornet.htm
Something i just tried to get rid of the crud ring was to duplex the load with 20 grains of American Pioneer powder then complete the load with T7 (100-20=80 grains). Worked well no ring a shot well.
My son and i took 2 does with it this weekend.