Cobra and Edward.
Cobra, I've found that by using bullets sized to .310" that leading is cut down and accuracy is improved. I've just started playing around with bullets sized to .311" and so far, results are interesting. I haven't done enough to make a decent judgement call though. The .310s work just fine though. I'm considering trying to shoot groups at 600 yards next, but I'm not sure my scopes have enough elevation adjustment in them to do that. Also, take note of my comments to Edward 429451.
Edward. You probably already know this, but just in case, don't use the brass from those light loads for full power loads down the road. You will run into headspace problems as when the primer fires off the charge, the case is driven forward pushing the shoulder back. However, while there is sufficient pressure to push the bullet out of the barrel, there is not enough to force the case bad and allow it to expand enough to fill out and form to the chamber.
I keep all my brass for cast bullet loads well separated from the full power load brass.
Shooting cast bullets is like getting a higher education in the handloading game. Anybody can read a loading manual and get decent results from the get go, but with cast bullets, well there is more work involved. However, once you get started, you'll find it to be addictive as hell. This must be true as I've been doing it for 55 years now and still haven't kicked the habit. I don't think I want to either.