Modoc Mike, (with that handle you must be a fellow prunepicker). Sorry it took so long to get back to you but I had to pick the brains of others, especially the most knowledgeable caster I know. The theory is that two groove barrels shoot best with bullets with bore riding noses because with so much of the barrel being lands there is a lot for the nose to ride on. In the real world four groove Springfields shoot bore riders very well, too. The Loverin type bullet (short nose, all of the rest groove diameter, multiple grease grooves) may be better for highest velocity loads. In the normal range of cast bullet loads ( 1500-1800 fps) there are a lot of very happy Springfield shooters with both styles of barrel. Hope this helps, curmudgeon
