most of swims friends that muscle tar shots every day do it with a standard insulin rig with 28g 1/2" tip. in the thigh, shoulders, biceps. despite the substance being tar, their results are rather surprisingly good. meaning they dont have abscesses often. the 3cc is a true muscle (IM) rig, and will go deeper into the muscle to prevent leakage into fat tissue, which to swim
seems like a better idea, but all the swimmers that muscle seem to only use the little rigs. swim sees no harm in using the 1" 3cc rig, as it will go deeper and prevent leakage into the fatty tissue layer.