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Why is not all the energy transfered from the firing pin to the bullet in a K'nex gun? Answered

When the firing pin hits the bullet in a K'nex gun, why is there some energy lost? If all the energy from the firing pin was to
transfer to the bullet, then the pin would stop before it hit the back of the gun. Is there some way to use all of the firing pin's
energy to completely transfer to the bullet?

Discussions

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TheDunkis

Best Answer 7 years ago

It's simple, when you push something and then slow down, the object you pushed keeps going roughly as fast as you were pushing it. It doesn't magically go faster than you were pushing it. But it takes less energy to make something with less mass move just as fast. Now, plastic is somewhat, well, plastic so there is a little flex in it to store extra energy, but with friction, the gain is negligible.

So, the point is that the ammo will only go about as fast as the pin was traveling and then the rest of the energy is wasted. The best you can do is give a pin a lot of acceleration room.

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~KnexBuild~TheDunkis

Answer 7 years ago

If the bullet was the same weight as the ramrod, would none of the energy be lost? But then the bullet is extremely heavy and it won't go very far.

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TheDunkis~KnexBuild~

Answer 7 years ago

Generally, yes. But then it'd take more energy to get it moving anyways. So, ideally you'd want a very small pin with a long drawback and somewhat small, but still stable ammo.

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~KnexBuild~TheDunkis

Answer 7 years ago

How do you get a small pin? If you used a small pin on a rail like the Lt. Licorice, then you could have a small pin with a long drawback.

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TheDunkis~KnexBuild~

Answer 7 years ago

Precisely. But for some reason, people don't really care for rail pins.

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~KnexBuild~TheDunkis

Answer 7 years ago

Why don't they like them? I have tried to make one, but the top rail was flimsy.

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TheDunkis~KnexBuild~

Answer 7 years ago

Probably because they're somewhat difficult to make. It's not a traditional style weapon so it immediately scares off people.

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~KnexBuild~TheDunkis

Answer 7 years ago

Yeah, that's probably it. If there was some way to make the top rail stronger,
then those kinds of guns would make regular pin guns obselete.

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TheDunkis~KnexBuild~

Answer 7 years ago

Give it another shot. My suggestion, use a side to side rail. It should be able to connect to the rest of the gun much better. And I think I'd prefer access to the pin from the top than the sides anywho.

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dr. richtofen

7 years ago

Probably, some energy is lost in the following situations:
- friction of the ram with the insides of the barrel
- it pushes the bullet a bit to the front
- etc.

For the complete transfering, you'll probably need to shoot the ram in an vacuüm to the bullet, and let it stop just as it touches the bullet