I have dabbled some with 4570 PP bullets over BP, but quite limited experiences out to only 450 yards. Interested in what bullets you use and recommend for 45 caliber muzzleloaders? I am mostly interested in hunting range accuracy, and with a muzzleloader find 300 yards, at least for me, is stretching it and actually a bit past my self imposed limit. Have tried purchased bullets with no grease grooves (believe they were .444” diameter 400 grainers from Buffalo Arms) but found them a bit loose in some barrels for hunting (they moved off the powder), although they were accurate.
The RCBS 11mm mold I have drops .447” diameter bullets with my alloy. I size after wrapping with paper to get the fit I want for each barrel for hunting (I use an adjustable sizing die). I also tried sizing down some .451” diameter smooth bullets, but struggled to get them to shoot well. It’s possible that the grease grooves give some advantage when sizing with paper already wrapped for use in muzzleloaders...... just speculation, but find the grease grooved bullets work for me in my muzzleloader barrels.
