A reloading question that I had never envisioned

[ReloadforFun]

Using the pressure model, what is the gun velocity. How would it be calculated?

Let's assume a 9mm 124gr bullet at 1,100 fps from a 4" barrel. And consider the gun weighing 2.5 pounds. If needed, use a charge weight of 3.5 grains.

Thanks. Wanting to learn more.
.

 

[BC38]

Using the pressure model, what is the gun velocity. How would it be calculated?

Let's assume a 9mm 124gr bullet at 1,100 fps from a 4" barrel. And consider the gun weighing 2.5 pounds. If needed, use a charge weight of 3.5 grains.

Thanks. Wanting to learn more.
.

Calculate Recoil Energy

 

[DWalt]

Using the pressure model, what is the gun velocity. How would it be calculated?

Let's assume a 9mm 124gr bullet at 1,100 fps from a 4" barrel. And consider the gun weighing 2.5 pounds. If needed, use a charge weight of 3.5 grains.

Thanks. Wanting to learn more.
.

MV (momentum)=FT (Impulse) MV (gun)=MV (bullet and propellant gasses). Just solve for V of the gun after you have calculated the Momentum of the bullet and propellant gasses. Be careful, as the mass must be calculated in slugs, not pounds. 1 Slug = Pounds/32.16

 

[ReloadforFun]

I understand the momentum method, but it does not include anything for chamber pressure. As I understood the above, the recoil is based on the pressure working against the gun.

When I tried to find the gun velocity based upon the chamber pressure it was several times larger than when calculated by the momentum method.

So, what I don't "get" at present, is how, based upon the statements above about pressure and recoil, how you determine the recoil (or gun velocity) using the pressure.

The link is also not using chamber pressure.

It seems the recoil energy must be found through a momentum balance, as it has been for a very long time, and not through the chamber pressure.

Thanks.

 

[robvious]

I love this forum... a simple loading inquiry becomes a discussion of Newtonian Physics.. do I get any CEU's for this?

 

[Johnnu2]

I love this forum... a simple loading inquiry becomes a discussion of Newtonian Physics.. do I get any CEU's for this?

COULDN'T HAVE SAID IT BETTER MYSELF

p.s. I never had a problem finding load data for that bullet probably because I don't over-think and certainly don't 'over-research' anything )))

p.s. what's a CEU?

J.

 

[dla]

Great stuff! Just to nit pick a bit, the velocity if the gas at the muzzle can run between 4000 and 7000 fps, depending on temperature, which is directly related to pressure. My point is that the mass of the powder charge, converted to gas, has a huge effect on recoil. Which is why comps were used (think 460 Rowland).

 

[Jaco1234]

Pressure is the force that accelerates the projectile
Pressure =force/area
Chamber pressure x projectile area = force

Recoil has 2 components
The force generated by the acceleration of the projectile(Newton's 3rd law) and the force generated by the gasses exiting the barrel (rocket engine)
Hatcher's notebook has a thorough discussion of recoil.

 

[STORMINORMAN]

Most likely the "CEU" = C(ontinuing) E(d-u-ma-cational) U(nits)...?

Cheers!

 

[ArchAngelCD]

Most likely the "CEU" = C(ontinuing) E(d-u-ma-cational) U(nits)...?

Cheers!

Correct... Many call it "credits" for life experience.

 

[BC38]

Pressure is the force that accelerates the projectile
Pressure =force/area
Chamber pressure x projectile area = force

Recoil has 2 components
The force generated by the acceleration of the projectile(Newton's 3rd law) and the force generated by the gasses exiting the barrel (rocket engine)...

...which is also an example of Newton's 3rd law

 

[Dusty Miller]

WHO?!

"It's Einstein's "equal and opposite" theory....." I think that was Newton!!