bronze,copper bullets lube grooves?

[Loppster]

Hi.
Tell me please, why make lube grooves in solid bronze or copper bullets ?
For cast lead bullets, ok , prevent the lead from adhering to the barrel . But why for bronze or copper?

 

[Grumulkin]

That's easy; they're not lube grooves.

 

[jr_roosa]

It decreases bearing surface, or the area of bullet contacting the bore.

http://www.barnesbullets.com/information/bullet-talk/faq/

-J.

 

[TNBilly]

in addition to decreasing the surface area riding on the bore the grooves give the metal that's displaced by the rifling a place to go. If you had the rifling imprinting the whole length, plus increasing the length of the bullet in order to do so the pressures would be substantially higher, probably unworkable.

 

[rcmodel]

Barnes did it in the first place on the solid copper bullets to prevent or inhibit severe copper fouling of the bore.

As noted, it gives the copper displaced by the rifling a place to go besides smearing off in the bore.

rc

 

[Loppster]

But much steel core TMJ not have grooves

 

[Edarnold]

A conventional jacketed bullet, with a thin jacket over a lead core, let's the lands push their indents into the jacket and into the core. Even 'steel core' bullets have a thin lead layer between the jacket and steel to allow this deformation. Any solid bullet, whatever it is made of, has a problem of dealing with the material displaced by the rifling. Pick up a fired lead bullet that is not damaged and you will often see little tabs extending from the base from the displaced metal. With brass or copper alloy the material displaced by the lands has nowhere to go unless the bearing surface is grooved. Early controlled expansion bullets by Winchester and others has poor velocities because the long bearing surfaces ran pressures way up compared to conventional designs, the grooved surfaces on the Barnes bullets you showed are an answer to that problem.

 

[Rushthezeppelin]

WTH is the second bullet in your post OP? Is that some type of wadcutter?

 

[788Ham]

Looks almost like a scale weight.

 

[PO2Hammer]

Not sure, but that 2nd bullet looks like an old design that was banned in Europe IIRC. Designed to provide maximum resistance in flesh to limit penetration and maximize energy transfer in the days before jacketed hollowpoints.

 

[armsmaster270]

I do believe it is the first bullet to penetrate bullet proof vests, made in france i think.

 

[brickeyee]

You do not need any special bullet from a rifle to defeat most soft body armor.

It would take a far larger number of layers, and then blunt force trauma rears ITS ugly head.

Plates have been the answer.

They spread the area out to limit blunt force, while managing to stop rifle rounds in reasonable thickness.

Metal loaded ceramic is a wonderful thing.

Crank up the vacuum pumps.