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If you use jacketed bullet data your velocities will be much lower with the plated bullets...
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cause the softer lead bullet will expand more in the barrel thus engaging more of the lands surface.
more friction= less velocity
more friction also goes to higher pressure.
less friction cause the case of a FMJ has a brinel of +35 compared to a ~12 to 18 for plated.
even though a FMJ has more powder the pressure is not much greater cause the
bullet is more slippery and there are more blow by gasses than a lead round.
recover a lead or plated bullet and a FMJ
note the deeper cuts made by the lands on the lead or plated bullet.
the lead bullet may also expand to touch the groves and there by,
since it can not expand any more, it lengthens.
this deformation takes energy.
less energy=less velocity
also since it has sealed the expanding gasses behind it,
the pressure remains high, unlike the FMJ which allows for blow-by gasses.
so, once the bullet is 'sealed' the pressure remains high thus helping the bullet along.
but a pistol is too short barreled for the gain to out weight the cost.
there is more to this.....
ain't there always??
bottom line--Follow The Manual
and cross reference. have 2 or more manuals.
do not get creative when reloading.