yeah...since I made the first post, I watched another EC's podcast and it appears that in the video I posted, he's talking about POI shift not ES/SD. so I misunderstood him.
But regarding unburned powder, that's another interesting point as well. does it cause high ES/SD? from time to time, I hear it does. and to me, it makes sense.
if the barrel is long enough so all of the powder is burned before the bullet exit the muzzle, then the push should be exactly the same each time. but if the barrel is not long enough, then by the time the bullet exits the muzzle, the amount of powder that has been burned up to that point might vary. it could be 91%, 92%, etc. each time and that causes muzzle velocity to deviate.
so if the above is true, then long barrels are inherently better in achieving lowest possible ES/SD, as long as they are long enough for a complete burn.
Mark & Sam made a video on "optimal barrel length" in which he said, if you continue to add barrel length after the powder has been burned completely, then that won't speed up the bullet and will only slow it down due to friction. so is it wrong to say:
whatever your current's barrel length is, if you replace it with a barrel that is 1 inch longer, and still see a speed increase, then that must mean the current barrel is not long enough for a 100% burn. because if it was long enough you would have gotten a speed decrease, not increase. and your ES/SD will never be as low as they could have been with an "optimal length" barrel?
I have asked 3 different gunsmiths and they all told me no. barrel length does not affect ES/SD. but what does everyone think?
