These numbers and weights will help show the difference between the density of lead 11.36g/cc shot and the density of TSS 18g/cc shot.
#2 lead shot has about 89 pellets per ounce, each pellet weighs about 4.91 gr
#2 TSS shot has about 54 pellets per ounce, each pellet weighs about 8.10 gr
#4 lead shot has about 136 pellets per ounce, each pellet weighs about 3.21 gr
#4 TSS shot has about 83 pellets per ounce, each pellet weighs about 5.24 gr
The TSS #4 pellet weighs more than the lead #2 pellet.