Re: velocity spreads
Poor Standard deviations are normaly load related not barrel
Poor ignition caused from old primers or powder.
Some times the primer can be to hot.
If brass is getting old neck tension can vary from round
to round.It may need to be annealed.or replaced.
Also check freebore (bullet to rifle lands) if you are
real close some could touch and others not.
Some times the lock ring on your dies can move causing
this to change.
I hope this will help
J E CUSTOM