I've played with the old Ideal Perfection moulds (adjustable nose-pour grooved bullets) and they did well (but perhaps an identical bullet in a base-pour would have done as well?). RCBS made an adjustable paper-patch mould for the .45 rifles that was interesting but took some work to get good results; other makers over the years have made similar moulds. From my limited experience with Eagan's moulds, it looked like his approach was to cut the moulds with cherries and have the chamber leade cut to match (which actually isn't a bad idea). One way or another though, these moulds all offered generic one-size-fits-all dimensions.
The reputation of nose-pour moulds (and the argument that they are better because of better bases) came from a time when the nose-pour moulds were custom-made to fit the chamber of an individual rifle. Often the bullets were tapered, to better-fit the leade. It might take several trials to get a mould with just the right dimensions for a particular rifle. There was no risk of the bullets getting messed-up in the sizers because they weren't sized. Of modern makers, Hoch lathe-bored his moulds, and you could get one cut to fit any chamber.
I've run tests with good base-pour and nose-pour moulds, checking weights and measurements. If I tuned the moulds and cast with all the tricks I've learned over the years, there was no difference in consistency. Which brings us back to the modern view that fit is king. Sometimes it is just easier to get optimum fit by using a nose-pour mould.
The reputation of nose-pour moulds (and the argument that they are better because of better bases) came from a time when the nose-pour moulds were custom-made to fit the chamber of an individual rifle. Often the bullets were tapered, to better-fit the leade. It might take several trials to get a mould with just the right dimensions for a particular rifle. There was no risk of the bullets getting messed-up in the sizers because they weren't sized. Of modern makers, Hoch lathe-bored his moulds, and you could get one cut to fit any chamber.
I've run tests with good base-pour and nose-pour moulds, checking weights and measurements. If I tuned the moulds and cast with all the tricks I've learned over the years, there was no difference in consistency. Which brings us back to the modern view that fit is king. Sometimes it is just easier to get optimum fit by using a nose-pour mould.