[axxe55]

Originally Posted by 1hole

"The powder burns completely in the chamber and a few inches into the barrel."

Not quite. Peak chamber pressure occurs within a very few inches of bullet travel but few charges are completely burned before bullet exit even in long barrels.

From ignition to bullet exit typically runs around 3-5 thousants of a second so the burn couldn't possibly be started and completed and the fire go out in such a brief time. With powder burn continueing the whole time there's no need for a secondary ignition when freed into the air and muzzle blast is determined by the remaining pressure at bullet release. Once the burning gases are released, most unburned powder kernels will extinguish; it's easy to find them in snow.

exactly true. burn rate of the powder has a lot to do with it. thanks for saying much better than i did 1Hole.

[OldManMontgomery]

http://www.navweaps.com/index_tech/tech-090.htm

Steve is correct. Virtually all the powder in a rifle or handgun that will burn has burned in the chamber and first few inches of barrel. Some powder kernels do not burn at all, but that's not because the charge was still burning.

Optimum burn rate of powder depends on ratio of bullet sectional density to charge weight.

The heavier the bullet (all other things being equal) the slower the powder for optimal power.

However, the smartest way to find it is as mentioned. Get a couple loading manuals and see what gives good velocities. Also, when one gets reloading manuals, one finds reading the introduction about all the components and assembly very enlightening.

Just for the record, I have a Remington 700 VLS in .308 Winchester and the best load I have for it is a military surplus 174 grain match bullet and 41 grains of IMR 4895. That uses Federal cases and whatever LR primers I can find.

[mountainskytop]

Back in the 60's and 70's when I last reloaded I used DuPont 3031 powder for rifle and UNIQUE for revolver. Are these two powders still around and recommended??

[OldManMontgomery]

Mountain Sky Top, both powders are still made and sold; both powders are still very useful as you describe. IMR 3031 might be a bit 'fast' for very heavy bullets, but for middle weights it should fairly well. Of course, check your loading manual as appropriate.

[mountainskytop]

Thanks for response. I used the 3031 for a .243 ground hog load pushing out a 75 grain bullet at MAXIMUM velocity/pressure!