Invisible hand holding a rifle still while the animation still plays

Disclaimer: My sole goal is to achieve a similar effect as stated below. I want to do it myself and I do not want to commit any theft. Thank you.

Hello there, fellow scripters. I am trying to come up with a certain animation for a firearm system I am making. I have created many types of it, yet I am struggling with only one - the bolt action rifle.

As many of you know, a tool can only be held by the right hand. Yet I have seen it is possible to make it either levitate in the air or be attached to something else.

I am trying to code a functioning bolt action rifle which will have its bolt cycled by the right hand. But I see no trustworthy way to do it. However, I found out that one bypass can be done:

For a second or less, the rifle freezes in the air. The most peculiar thing is that it does not freeze by any coding, but by a physical arm holding it. The said physical arm is invisible or overriden, but it holds the firearm when the cycling animation runs smoothly.

Here is the visual representation of what I am talking about, both what the player sees and what the player would see if the arm was not visible:

https://streamable.com/sc1814

My question is: How would it be achieved?

Which variables and functions would need to be used to suddenly make the Humanoid’s right arm still and holding the rifle while its visible counterpart is still performing the animation? Is it a clone?

I will be grateful if one of you will lead me towards the explanation.

Best regards