Ok, well, I'm not sure if reaming it will allow for better metering but it will help the consistency of what falls into the case. The reason I say that is that the bar's metering won't change. The drop funnel can, however, allow powder (especially stick powder) to bridge, thereby giving you a short charge. Two things you can do to fix this:
1. Get a 3/8-5/8 taper reamer (the size really isn't important, but this is a popular size) and run it down the throat of the drop funnel (in the same direction the powder falls) and ream out the funnel to get rid of the shoulder in there. Now, this is important!!!!-----> Don't ream until the ridge at the bottom (where the case mouth goes) is reamed out. That part needs to stay. Otherwise just ream till you're tired of reaming.
2. Modify the toolhead to accept a 650 powder check die in the third position. I think there ought to be some old pics of my toolhead here if you search hard enough. This way you get assurance of a full load every time or it will squeal.
I would say that with good dies, reaming the drop funnel, careful and consistent machine operation, and the powder check die in place, you should be able to produce ammo that is indistinguishable from Rockchucker produced ammo out to at least 600 yards, perhaps even 1000...at least in the realm of my past test bed, Highpower Rifle. The powder check die is far pickier than you might expect (and the more narrow your neck and the more powder you have it gets even more accurate) and you can set it up so that it will kinda error check your powder charges for accuracy too. Many handloaders agree that powder accuracy is more a function of volume than weight. If you feel like subscribing to that theory, the powder check die will give you a second volumetric test of each load. After you have it set up this way you can load pretty quickly, only stopping when the powder check die squeals about a load that is .05 grains too hot or cold. This method DOES make you put the bullet in the case with your right hand. Kinda awkward, but worth it I think.