The firearm thread

[frogfeaturesFZR]

What you are aiming for ( excuse that ) is the rifle barrel 'ripples' the same way for each shot. The barrel actually ' moves' microscopically as each shot passes through it. As it heats up and expands, where it was free floating before it may touch the fore end as it expands. Different point of impact. Heavy barrels heat up more slowly. Facinating subject, google rifle bedding and have a read.

[jono035]

http://img.photobucket.com/albums/v3...sixpounder.jpg

That's the dimensioning of a 6lb 1841 field gun. Bronze cast, weighs 400kg.

1/2 scale is 1/8th weight or 50kg.

Seems pretty reasonable, 125mm diameter barrel at the thickest point, 760mm barrel length.

[The Pastor]

http://img.photobucket.com/albums/v3...sixpounder.jpg

That's the dimensioning of a 6lb 1841 field gun. Bronze cast, weighs 400kg.

1/2 scale is 1/8th weight or 50kg.

Seems pretty reasonable, 125mm diameter barrel at the thickest point, 760mm barrel length.

why is the 1/2 scale 1/8th the weight?

[jono035]

why is the 1/2 scale 1/8th the weight?

if you halve all the dimensions then you have (1/2)^3 the amount of material

There are 8x 0.5" cubes in a 1" cube...

[The Pastor]

so it'd shoot a 3 pound shot?

[jono035]

so it'd shoot a 3 pound shot?

No, 1/8 * 6 so 0.75lb or 341g.

Volume = 4/3 * pi * r^3

Same deal.

[The Pastor]

oh...... maths is misleading

[Indiana_Jones]

I think you melted his brain.....

-Indy

[jono035]

Still wondering about the cartridge brass as a cannon material. It says that it is a good material for cold working which makes me wonder if it is going to expand and either create a void between the brass and the barrel sleeve or harden and split/explode.

Of course, if we use loads that the steel sleeve will fire on its own then that is moot point, but unless you can load it up and stick a concrete-filled beer can a couple of metres deep into the cliff then whats the point

[jono035]

I think you melted his brain.....

-Indy

I did 4 years of crazy maths for engineering, I got used to living with a molten brain

[Indiana_Jones]

I did 4 years of crazy maths for engineering, I got used to living with a molten brain

Everyone knows the ginger beers are lazy bro!

-Indy

[jono035]

Everyone knows the ginger beers are lazy bro!

-Indy

... uhhh, wtf??

[jono035]

Ahhh balls, I forgot about the beer-can projectile requirement.

For a 67mm diameter bore then that is a 1:1.4 scale which leads to a weight of 146kg.... Hmmm....

[wbks]

Any of these in NZ?

[Wolf]

Any of these in NZ?

Oh, fuck, I hope so!