You don't cite velocities, I notice. You assert that their popularity proves ipso facto that they must produce more velocity than a 24" barrel. But your observation's irrelevant in any case, I don't care about any 6mm, BR or Dasher, only specifically 6.5 Creedmoor. The barrel chop study I cited lays out the complete velocity data for your inspection. Did you find the study is flawed? If so, in what way?
What you don't know are the velocities those exact same loads would produce if you cut your barrels to 24 inches.
I don't own a Creedmoor rifle. Nor do I own a 24-in barrel. This is not a debate. I simply cited empirical evidence (a controlled experiment with complete data) and all I get in rebuttal are anecdotes, assumptions, speculation, and argumentum ad verecundiam. If you're going to prove the experiment flawed, then prove it flawed. Where and how did the test go wrong? Don't just say everyone knows it can't be true, and cite the popularity of 30" barrels.
You are spot on, there's nothing magical about 6.5 Creedmoor. It has a modest case capacity compared to nearly every other 6.5, the notable exception being Grendel.
I agree, except for one small item: Acceleration is never increasing here, it is decreasing constantly. The acceleration (instantaneous positive slope of the velocity curve) is greatest immediately after the bullet starts moving. By 26 inches down bore, acceleration is slight.
A lot of people are shooting 32 inch barrels in FTR for the reasons depicted in that chart. Basically the powder burns rapidly, building pressure rapidly and dropping off rapidly a first and then more gradually as the bullet makes its way to the muzzle. However, as long as the pressure is high enough to overcome the friction of the bullet against the interior of the barrel and the atmospheric pressure, increasing acceleration will be the result. It would take a very long barrel for the pressure to drop low enough for the bullet speed to drop below it's peak velocity prior to exit from the barrel. These are the physics of the sport we are engaged in. If someone claims to have experiments which run counter to these physics, I'd speculate that there is something wrong with their experiment.
That aside, I'm getting about 2800 fps using H4350 from a 28 inch barrel with Berger 140 hybrids. I've tried higher and lower charges which yield increased and decreased velocities but 40.9 gives me the best accuracy at an acceptable velocity.
If you are going to cite one experiment and proceed to assume the results are fact....that is the flaw!. One experiment when the vast knowledge base says otherwise? ........Sheesh! If under several different circumstances and different experimenters, the same results are obtained then I would begin to make some conclusions of fact.
I'm not insisting the test I cited cannot be flawed in some way, or that the result must be valid. But unfortunately it's the only such barrel chop test for 6.5 Creedmoor I can find. The procedure seems simple enough, and I cannot detect where it might have gone off the rails. There is one variable which stands out - the testing was performed in cold ambient conditions: temperature of 23f. Could that have affected a greater-than-max (Hodgdon data) load of H4350 enough to cause velocity to peak at only 24 inches?
I wonder if the test barrel had a really tight bore? Or was rough? About the only explanation I can think of is higher-than-normal friction.
We are saying the same thing. What you said that I disagreed with was (emphasis added):
