I have some 178 gr Lyman 358429 bullets. Want to use Unique and 2400. I would think my usual mid range load of 6.0 grs Unique and my Magnum load 12 grs 2400 will be fine for this heavier weight 178 grs. I seat the bullet to 1.553” OAL.

Any suggestions with a heavier weight 178 gr 358429?

How did these bullets come out so heavy? Did you add gold to the alloy? If this is for a .357 Magnum, I think you'll be fine. I've actually used heavier loads with a 180 grain flat point bullet in my Model 28.

...I purchased them from Matt’s Bullets (excellent bullet casters) and do not know the composition but they note on their site that they use a semi hard alloy with a hardness of 11 BNH.

My notes indicate the #358429 I've cast myself weigh about 170 grains in an alloy that is approximately of wheelweight hardness - about 12 -13 BHN. The Lyman book says theirs weigh 170 grains from linotype alloy which is supposed to be about 22 BHN. I'm sure there have been many different cherries used in making these moulds over many years and that would cause a little weight variance. Perhaps that would account for any discrepancy, but I suppose it's really not all that great, probably not enough to change load data unless you're loading pretty hot.

I shot some Missouri Bullets 180 gn Pugnose (flat point) with 12 gr. 2400 in my GP100 and SP101. No problems aside from being uncomfortable in the SP101 as I'm a bit sensitive to recoil. FWIW I think they're around 18 BHN.

I'm going to start using 6.0 Unique for my regular 158 gr. mid-range loads now and save the 2400 for rifle use.

The heavier weight is from the alloy, more lead less tin/antimony. You’re right in the wheel house with your loads. I’ve gone to 13.0 2400 with that bullet and no problems in my guns. You didn’t say what gun. If it’s an N frame Smith you may have to crimp over the driving band to get them to fit. The softer bullet from Matt’s can cause some leading if driven too fast.

Dan

My go to load using the Lyman 358429 cast bullet is 7.0 grs of Unique or 13.5 / 2400 . I load them in K and L frame 357's , loaded them in 357 cases , crimped in the crimp groove . Those 2 loads are so successful for me that I don't need others , different powders or lighter loads . Regards Paul

I load them 1.553” OAL “short” so they can also fit in my SP101. I also have a Ruger Blackhawk -although the Blackhawk can use the 358429 in its crimp groove, I prefer to have one length to accommodate both the SP101 and Ruger Blackhawk.

If you load these in .38spl hulls,they're hot but ok if shot in .357 Mag guns.
If loaded in .357 brass,I'd put them in the medium class.