I'm not sure why you're saying the slug failed. Is it because you had to make a follow-up shot or because it didn't penatrate. I find it difficult to believe that a slug did not shoot completing thru a deer at 30 yards.

Because you've had two bad experiances with the SST's, I would suggest that you go back to shooting your previous ammo. When any hunter fails to have convidence in his ammo or gear, it's time for a change.