Calculating tilt from an AR-15

[gutymaule98]

Summary:: NEed to calculate tilt of AR-15 for school project

Hello, I am creating a rifle simulator prop that will recreate realistic recoil without firing a bullet. MY idea is to use pressure gas leaving the tip of the gun in a downwards position to recreate the tilt, just like the opposite of a compensator. However, I have been struggling to calculate the tilt of the gun from shooting a bullet.

 

[berkeman]

Welcome to PF.

By "tilt" do you mean "recoil"? You would need to have a mechanism to create a backward pulse on the stock to simulate the recoil.

 

[Klystron]

Recoil moves the rifle in the opposite direction to the projectile, back into the stock. Tilt refers to the tendency of the barrel to rise when fired. Compensators vent the exhaust gases upward to compensate for this tendency for the barrel to rise, and backward to offset recoil. Check?

https://en.wikipedia.org/wiki/Muzzle_rise#Reason

 

[Dullard]

Your post is very weapon-specific. Under those circumstances, it may be necessary to consider the fact that the 'recoil experience' of an AR-15 includes the operation of the bolt. Just before the round leaves the barrel, the bolt is unlocked and 'blown back' with gas. a buffer spring is compressed by the bolt's rearward travel (several inches) and then it accelerates forward and strips a new round from the magazine. When it hits 'home,' it stops (suddenly) and (hopefully) locks. 'Recoil' for a gas-operated weapon is complicated. All of that is to say: There isn't a simple way to 'calculate' the recoil (or the effect of recoil on weapon 'tilt.')

 

[Klystron]

All correct. Simulator implies simplification. One can ignore most of the internal mechanism complexity, specific AR-15 variations and concentrate on the (x, y, z) axes to plot motion.

One can even ignore the bullet in the calculation as the escaping gases when an actual rifle fires provide enough impulse to

1. kick the rifle back (recoil), and
2. rotate the rifle upward ('tilt' or muzzle rise).

Both are explained by Newton's laws of motion, tilt or rise because the operator grips the rifle near the back while the gases expand from the front.

[Edit: corrected misapprehension. No actual weapon parts nor ammunition should be near any school.] Simulator can be made with a stick or ruler. Tap the 'muzzle' to simulate firing.

 

[berkeman]

One can even ignore the bullet as the escaping gases provide enough impulse

I don't think we should be encouraging the OP to eject anything (including high pressure gasses) from his prop. So far I'm not thinking that would be safe. But...

Summary:: NEed to calculate tilt of AR-15 for school project

Hello, I am creating a rifle simulator prop that will recreate realistic recoil without firing a bullet. MY idea is to use pressure gas leaving the tip of the gun in a downwards position to recreate the tilt, just like the opposite of a compensator. However, I have been struggling to calculate the tilt of the gun from shooting a bullet.

Can you tell us more about this "school project" and the need for a "prop AR-15"? Is this for the drama department to use in an upcoming play perhaps? We have rules here at PF about dangerous discussions, and a discussion to help you try to build a stage prop that expels high pressure gasses is not going to happen here.

If this is for a play, does it only get fired once, and you just need it to simulate the recoil once so it looks more realistic? Or is it used in semi-auto rapid fire mode? If the latter, how many recoils in a row do you need to simulate? How much time between simulated shots?

And if it is for a student play by the drama department, I would have to ask what in the world is the play about? Perhaps some scenes from "Apocolypse Now"?

 

[Bystander]

scenes from "Apocolypse Now"?

Recoil is recoil and never been "simulated" at all "realistically" in movies...just does not happen. The "old cowboy/oater" exaggerated movement of wrist/arm is/has become standard dramatic technique.

 

[berkeman]

Recoil is recoil and never been "simulated" at all "realistically" in movies

Agreed. Ever seen an actor flinch when the gun goes off?

 

[Klystron]

This may be an 'abandoned' thread? OP wrote 'calculate' as if for a physics class.

My granddaughter tells me that even toy weapons are not allowed on campus.

 

[berkeman]

My granddaughter tells me that even toy weapons are not allowed on campus.

Yeah, good point.

 

[hmmm27]

Summary:: NEed to calculate tilt of AR-15 for school project

Hello, I am creating a rifle simulator prop that will recreate realistic recoil without firing a bullet. MY idea is to use pressure gas leaving the tip of the gun in a downwards position to recreate the tilt, just like the opposite of a compensator. However, I have been struggling to calculate the tilt of the gun from shooting a bullet.

Waaay more information is required, here. Mostly "Why ?".

 

[berkeman]

Thread is temporarily locked for Moderation. @gutymaule98 send me a PM (private message -- click on my avatar and Start a Conversation) to answer the questions that you have been asked in this thread. If your answers are okay, the thread will be conditionally reopened. Thank you.