Changing the CBTO will change the pressure characteristics of the load which if you jam will increase it & imo hence give you slightly more velocity than when a projectile is seated deeper into the case.
Will it be more accurate?
Usually, but that's the thing with reloading, you are able to 'fine tune' the load till you get the sweet spot.
By sweet spot I mean the whole idea is that your load reach the optimal barrel timing.
You barrel when a around is fired will oscillate, the load that should perform best its the load that creates the best 'harmonics' when leaving the barrel.
http://www.the-long-family.com/OBT_paper.htm
I start all my load testing @ 10 thou CBTO & go through the powder increments at .3 to .5gr depending on what is the min to max load until I find the nodes(sometimes 2), then I take the best powder charge & change the seating depth to 5 thou & to 15 thou & sometimes 20 thou depending of the results.
Using the above method I have normally found a result of up to .5 moa in 30 to 40 rounds tops.
Occasionally If am still not happy then I change powders & try the process again.
**Whatever you do if your going to change your CBTO you should work up the loads from the start, that's why I always start from 10 thou & work up.
