Does ballistic gel give an accurate depiction of bullet penetration?

I've been watching videos of guys firing different types of ammo at ballistic gel etc. And penetration tests seem impressive on video and hard to believe in real life. Is ballistic gel supposed to mimic human body's density ? Side Question: The difference between a 9mm round and a 9mm Mak is rather... show more I've been watching videos of guys firing different types of ammo at ballistic gel etc.

And penetration tests seem impressive on video and hard to believe in real life.

Is ballistic gel supposed to mimic human body's density ?

Side Question:

The difference between a 9mm round and a 9mm Mak is rather miniscule but the effect on the same target is obvious, the 9mm is more powerful. Why is that ?
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