What do you mean by

"loading the powder in halves, compressing it in two operations before installing the bullet."

How is this done and to what purpose?

The Turk 8x57 ammo is 154gr, not 196, and 2900 fps is in spec for military ammo.

Some all time great loads, discovered by handloaders and not factories, are compressed. H4350 with 400 gr bullets in the 416 Rem Mag comes to mind. It gives higher valocities at lower pressures than any other powder and is unaffected by heat. Consistency can be as low as plus or minus 12 fps.

IS there any scientific proof that by the stick powder breaking that it does change the burn rate? I have a hard time with this as I was an extrusion tech at one time. Unless you are measuring every single granule of powder for size and length, you have incosistancy in every grain you put in your case. Just look at your powder and you will see grains of every size and shape. You are not changing the chemical composition of the powder thus the burn rate itself is not changing. I think it has more to do with the atmoshpheric pressures within the case that is changing along with how well the flash can travel in the case, and how the bullet is being pressured by the powder. thus changing the way the bullet will exit the case that is the cause of the variences found in "over" compressed loads. I may be totally off here but this makes more sense to me and just my take on it, no offense to anyone please.

Breaking powder grains both increases the total burning surface area and exposes bare nitrocellulose without the deterrent coating. It'll obviously increase the burning rate of the fractured grains. How much would be hard to predict. I found a scientific paper online a while back on how the aging of nitrocellulose propellants causes the chain length of the molecules to decrease, making the powder more brittle. Loss of nitration with aging only decreased the enrgy content of the powder by 1-2% at most, which is negligible. But the more brittle old powder is more likely to fragment when the primer fires, especially under high loading density, and the increased burning rate causes pressures to rise rather than fall as one might guess. Some military ammo's had to be taken out of storage and scrapped because of the pressure going too high on firing. It's more of a problem with single base powders, but also occurs with the low nitroglycerine content double base powders like ball powders according to the paper. That's not directly addressing the effect of breaking powder grains in loading, but is relevant. The key problem would be getting the amount of fracturing to be consistent for good accuracy, if fracturing's occurring.

Oh yeah, there are papers online that refer to the mechanical effects of propellant grains jamming against each other and the chamber walls, obstructing gas flow and fracturing grains. This stuff happens. Consistency's the key again.

There's nothing wrong with compressing powders. As a matter of fact it's totally desirable to use a powder too slow for your cartridge and loading the powder in halves, compressing it in two operations before installing the bullet.

Just work up to it as in all reloading situations.

There probably is scientific proof but I sure couldn't tell you where. I'm sure any of the powder companies could provide it. While certainly a few fractured granules in a compressed load might not make much difference, if any, carry it to extremes for your proof. Take a known given powder charge, mash a like charge up pretty good with a hammer and load each in two different cartridges. I sure wouldn't want to gamble and pull the trigger on the one with the fractured or pulverized powder. All the manufacturers and all the published information will tell you that two things control the rate of burn of a smokeless powder, the size and configuration of the granules, and the coating which serves to delay the burn rate. Expose the uncoated part, or remove most or all of the coating, and you'll have a faster and totally different burn rate. It will logically just depend on the extent of the pulverizing or fracturing.



Bottom line, if you are going for extreme accuracy and consistency, changing the propellant by cracking it, can't be beneficial.



I notice your handle. Any experience with loads for 160g bullets in a 7STW? What propellant and approximately what range of charge?

Thanks for all the input, I dont think I'll worry about compressed loads with stick powder.


Simdow