FMJ vs Cast load data

[RedDiamond1944]

I have 155g cast bullets gas checked (.311), I also have a box of Sierra 303 150 gr jacketed SP(.311). Been reading my Lyman reloading book searching for load data for the cast bullets with no luck. My question: is bullet weight equal for both types of projectiles when determining powder charge ? Can I use data for a 155 gr FMJ to load my 155g cast ?
This of corse is for my WWII era bolt action Mosin Nagant

[websterz]

Gas checked cast can be loaded with jacketed or FMJ data for the same weight bullet. +/- 10 grains will have a negligible effect. As always start with 10% lower powder charges and work your way up. That is true for any published data.

[joelvca]

Another factor, but of secondary magnitude, is bore friction. For bullets of equal weight and otherwise identical loads, jacketed bullets will generally shoot somewhat slower. Since it is challenging to get conventional cast bullets to perform well at normal velocities in high-power rifle cartridges, direct comparisons are usually with reduced loads or in medium-power cartridges like the .30-30, and I have faint recollections (CRS syndrome) of differences in the 50-200fps range, depending in part on velocity range and bullet shape, and sometimes with different POIs because of different barrel harmonics. This can become significant at plinker velocities, where a load that is perfectly fine with cast bullets can give jacketed bullets rather uneven velocities (from slight differences in bore condition), It can even leave one stuck in the bore, although this is much more likely in revolvers than rifles or postols. Bore friction also affects jacketed bullet load dynamics - I've seen reports of a round-nose bullet with a long full-diameter section shooting close to the POI of a spitzer in the next-heavier weight.

Regards,
Joel

[RedDiamond1944]

Great ! Thank you both ! I will start with the minimal charge for the 150g jacketed SP to load the gas checked 155g cast. I just enjoy plinking ( tho I do like to see good results ) and I was just researching for safety.
Thanks for the help.
RedDiamond1944