Wrapping My Head around Some Thoughts

[ET]

Trying to have a better understanding about powder ignition and pressure relationship can sure cause a person’s head to spin.
What I try to do for myself is compare what is happening between CF rifles and ML’s to hopefully find some answers.
With a CF rifle system we have basically 3-differences from a ML’er.
1) The thermal energy of a primer is directly dumped into the volume of powder.
2) Bullet engraving into the lands.
3) Specific size powder chamber.

With the ML we have a restricted setup that controls the amount of thermal energy from the primer delivered to the powder. This suggests a softer starting burn of the powder is achieved. The principle of burn rate from pressure built up still exists but is altered as seen from the resulting pressure and velocities.
Now when this step of engraving the bullet into the lands is eliminated the volumetric space for housing pressure is increased and again the combination of pressure and burn rate of the powder is altered.

To offset this condition a much faster burning powder can be employed as seen with the recommended loads by Savage. Two other approaches to offset this condition is increasing the thermal energy delivery or going to a duplex load which involves a fast booster initiating a reliable burn and a main load that carries the desired characteristic of the end result burn.

Now the introduction of a powder chamber sort of peaks my interest. By increasing the volumetric space that houses the powder and the principle of powder burn rate from resulting pressure build up suggests that this would soften the start of the burn. Again the desired burn rate can be achieved by altering certain variables. Whether a powder chamber can be beneficial or detrimental has yet to be determined and is probably the next phase of ML pioneering.

Even though I have reached a desired pinnacle with my 10ML-II, 50 Cal and a few unfinished load projects I still enjoy watching for what lies ahead.
In my post if I have missed any important variable or factor feel free to chime in with your comments as I don’t have all the answers and always seek additional info I may be overlooking.

As for back pressure through BP or obturation I have left these items out because I consider them as separate resulting entities that require their own discussions.
I believe Fishhawk said it best when he said “It’s a balancing act”.



Ed