Most agree that 1500 fps is about the top velocity a plain based boolit can survive.
The reason is the base of the Boolit gets distorted.(trailing edge burnt)
Simple as that, and we all know that the rear end is the steering end of a boolit, thus any alteration of it has negative results.
Just slowing down to around 1400 FPS will usually change the results dramatically for the better.
Also slower burning powders work better in rifles. H110/W296, 2400, AA9 but are better served in faster loads in the 1600 FPS range with Gas Checked Boolits.
The 8 gr of Unique with a 250 gr 429421 is a good place to start for a PB Boolit. Nice mid range load that also works well in Magnum Revolvers.
As someone stated above the Nominal Groove Diameter for a .44 Magnum Rifle is .431 and then add or subtract from that (+/-) .002 and still be within tolerance. So if your barrel is on size at .431 a .432 boolit would be the correct fit.
The reason why Rifle Barrels are larger than Revolver Barrels is because the Rifle has a closed and locked Breach, and thus must contain all the pressure until the boolit leaves the barrel. A Revolver has a gap between the cylinder and barrels which relieves some of the pressure. So the rifle barrels were opened up slightly to cope with the pressure difference.
Randy
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