Punching bag weight?

[guy incognito]

Lately I have been thinkinking of buying a heavy bag.I have changed my mind after hitting some heavy ones though.I have come to the conclusion that this will teach me improper mechanics.After all a heavy bag is closer to the weight of a person but it is tethered to the roof and a person is attached to the ground.Therefore if you hit someone in the head you are hitting the 2-3 kilos or so of weight of that persons head(For a head shot)The rest of their body will folow when they go down.But if you hit a heavy bag(Say 60kgs) your hand has to move all that 60kgs.A person pivots at the waist but the bag pivots from the roof.I found that the heavy bag doesnt allow for my follow through and my hand just tranfers its force and stops.What do you think.
All thoughts welcome.

[Thai Bri]

People get too macho with bags. They reckon that more weight is better. I disagree. I have two bags, one four feet (which is about 45-50 pounds in weight) and a six feet one (about 60 pounds). They are heavy enough, for the reasons you outline. And I can hit as hard as anyone I know.

[guy incognito]

Yes im starting to think that rather than being benifcial a heavy bag might injure me.