You guys are right, ES will open the groups up at LR, but that's nothing to do with the barrel being whippy, or stiff and its accuracy per say.
Tuning to a node, whether it be narrow or wide, which is more tolerant of ES, and the reasons seems to me what Mike is driving at here??
The whippy barrel may dwell longer and therefore be more tolerable of ES within a node, and this consistant exit will affect accuracy at LR, but if the ES "is" tight, shifting the MV to the node on a stiffer barrel that might not be as tolerant should be easy enough.
If you need a whippy barrel to tolerate a 50 fps node or more, 50 fps ES isn't going to make up for the fact that at 1000 yards ES does kill you.
Working up a load on the right side of the node may cancel out some of the ES caused dispersion, but it won't remove it all. Working on the wrong side of the node, if you go to this degree to find which side you're on, "would" make ES and dispersion in effect, stack up.
The stiff barrel may not tolerate MV shifts as well if the node is narrower, and temp insensitive powder and tight MV control in charge weight could be a must to deal with it.
How much does temperature have on the vibration itself?
How far off can your MV be before it starts to string shots?
What's the high level, and low level... node width in MV?
When you go too hot, which way does it string shots, down low, or up higher?
Ideally you want a load that starts to string shots lower as you peak over the intended MV range, and stay away from the low side of the node. Unless by going lower on MV, shots begin to actually rise, then this would be the side to work on, and avoid the other side.
If I've got a load that does great at 70 degrees F and only works to 40 deg, then goes stringin shots, I'd have to take ammo at a different charge weight to compensate for MV change if I was hunting at 20 deg, that or alter seating depth if I could compensate for barrel time enough that way.
Charge weight creates the pressure and MV that creates the vibration, so if that changed enough, seating depth may not necessarilly make up for it. Easier to load for a target MV anyway, then everything should remain the same...
This one load I have for the 30-338 Lapua, it's near max load, and just before it got to that level and stabilized, it jumped about .75 MOA on the target!
If I let the MV fall backwards, I'll not only be dropping .75 MOA from POI shift, I'll be stacking the lower MV on top of that.
I can't go any higher to get to the other side of the node, pressure's too high, so a downward POI shift as I increase MV just isn't possible with this load at this OAL
, I very well may be able to alter that by increasing the OAL .020-.030" into the lands, just don't know yet.
Here's a pic of the load. 210 JLK 90-97gr Retumbo 30-338 Lapua. 95gr on up grouped high. Circle is 2", fired at 300 yds.