A Point to Ponder

All the powder that is going to burn WILL burn by the time the bullet has traveled but a few inches. A pistol in 7mm-08, for example, will produce maximum velocities with roughly the same powder as a rifle in 7mm-08 with a 22-inch barrel. Muzzle flash, noise, and all that may vary, but optimal powder selection will generally be the same regardless of barrel length.

What I try to do is find a powder that will fill the case under the bullet and yield safe but "maximum" pressure (and by esxtension, velocity). After that, ease of metering and temperature sensitivity are determining factors in the final selection---IF accuracy expectations/requirements are met.
 
Last edited:
Quote:All the powder that is going to burn WILL burn by the time the bullet has traveled but a few inches.. Having been the first officer on the scene at several close range shooting fatalities, how do you explain the "tattooing" that occurs from unburned powder particles that are imbedded in the skin of the victim, if all the powder is burned within the barrel...??

If the powder is burned totally, long before the bullet leaves the muzzle, then it stands to reason, in my mind, that the friction of the bullet traveling through the barrel length will be actually slowing down before exiting the muzzle and a longer powder burn would keep the velocity up to it's maximum potential by keeping the pressure more constant.. Thus part of the reason for the difference in the burn rate of individual powders..But I may be wrong in my assumption...
 
SEE? There ya go, pondering again
grin.gif
 
I understand what you're thinking Turtle, but I would point out two things...first, you may never see 100% of the powder burn, and the second thing is the fact that the powder charge may have already converted to gas does not mean that it is no longer expanding and imparting or adding to velocity.

If you study some pressure curves you'll notice that peak pressure is reached waaaaay early in the bullets journey down the bore. "Flame" emitting from the muzzle and unburned powder do not mean that the powder did not have time to be consumed.
 
Originally Posted By: CatShooterOriginally Posted By: shipplyYou have proably seen this before but it is an interesting read, it may help you in your quest for the perfect powder combo. www.the-long-family.com/OBT_paper.htm

There is one major flaw in that theory.

When using a strain gauge to measure pressure, it does this by measuring the expansion of the barrel - the gas pressure causes the barrel to swell or bulge, and the instruments measure the change in resistance of the gauge - it's easy!

Now, the velocity of ANY wave in steel is ~18,000 feet per second. Since the barrel is ~2 feet long, and the transit time of a bullet in a barrel is between 2 and 4 milliseconds, then by simple math, this "shock wave" will travel back and forth in a 24 inch the barrel a whole bunch of times, before the bullet leaves the barrel.

I have looked at hundreds and hundreds of pressure curves, as have many others, and I (nor anyone else) has ever seen a pressure curve with these reflecting shock waves super-imposed over the main trace.

It is Dan's "theory" and he believes it, but there is less than "0" science behind it.

If it were true, it would be soooo easy to demonstrate it, instead of having to use "simulations".

Any theory can be presented with "simulations", but simulations are not proof or evidence - in college, his presentation would get a "F".

When the real proofs are so easy to produce, why is he still using simulations after 8 or 9 years.

Because there is nothing to it.






I am not a physics proff, so I can't argue with you. I do know between OCW and OBT, and using quick load with the extra info, you can ussually find an acceptable " Hunting load" with minimal work up time invested. Like he says these pratices are for helping develop hunting loads, not up to bench rest standards. It also hepls knowing burn rates and what each burn rate is doing pressure wise and effiecency wise while firing.
 
Back
Top