what powder???

[686]

With all else the same why does one powder shoot a tighter group than another ? same bullet, fps, seating, case gun, primer . is it cleaner not to foweling or durty too fowel, may be faster burnibg or just why ? i would think if you had a gun set up with a load at 3000 fps , that any powder you used and had 3000 fps you would get the same group. i know you may not and do not know why. thanks Charles

 

[ShootDots]

Well I will give you my "theory">>whether it is right or not, I don't know.. Powders, just like bullets, cause barrel vibration at a certain "frequency" if you will... When that "frequency" has the bullet exiting the barrel at the same point of the "wave-length" of that frequency, you will get a tight group. Send that same bullet out on a "varying frequency wave-length" and as it exits at differing points on the wave-length>>>you will not get good accuracy. Now there will be much more knowledgeable shooters on here who can either correct me or expound on this theory to a more accurate degree.. However, I believe that is essentially correct..

 

[lpreddick]

i agree and will add the concept of pressure spikes. if you could get EVERY kernal of powder to burn in the same nano second the pressure curve would be perfectly smooth and the bullet would go from still to it's peak velocity and exit when the barrel harmonics were right printing a single hole. however, the kernals burn at different times and produce several pressure spikes with the bullet "starting and stopping" with each spike, then finally exiting with the barrel that's vibrating differently to each spike. i'v read there can be as many a 4 pressure spikes with some powder. the physics here are COMPLEX and i don't understand 99%. "accuracy nodes" are often related to mv but we have all seen crappy groups when the mvs were the same with different powders. extreme accuracy is usu seen with the faster powders...kernal retardants do what they are suposed to do...affect powder kernal buning. as always, i reserve the right to be totally wrong.

 

[686]

wow a lot to think about. i guess , try it, like it shoot it. thanks Charles