I am loading for a full power .357 Magnum load for the first time.  I have loaded tons of .38 special and some light to midrange .357's.  I will be using H110 and HiTek coated 158gr cast bullets with a Brinell harness of 18. It is these.  I'll also be using Winchester WSPM magnum primers and mixed brass.  I am seeing some confusing data and need some advice where to start.  I'm seeing some advice online about using soft lead data and other saying jacketed data.  I am working out of Lyman 49th and Speer 14.

Speer's only loading for lead 158gr is for low velocity and doesn't reference H110.  All of their other data is for jacketed.  Lyman 49th has loading for Linotype which I thought was soft lead, and jacketed.  These are the two closest matches I can see in Lyman:

Linotype 160gr min: 15.8 / max: 16.5
jacketed 158gr min: 16.3 / max: 17.0

Should I be following the Linotype data with a good crimp and just watch my pressure signs?

I don't know if it makes a difference but these will be shot our of a GP100.

Any advice is greatly appreciated.

I load coated bullets the same as lead.  I know some folks load it the same as plated, but I've had zero issues at cast speeds.

I've loaded Precision coated bullets to jacketed velocities; with no leading whatsoever.

I do get the black coating in the barrel but it comes right out.

Did you start with lead or Jacketed data?  I don't currently have access to a chronograph so I'm just watching pressure signs.

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I've been using lead data for PC'd bullets.  And I get same velocities as published data for lead loads.

That’s perfect.  Your load is just about exactly what I’m looking for.  Thanks.

Since it doesn’t appear to have been covered yet, Linotype is NOT soft lead. In fact it’s actually pretty hard.

12% Antimony
4% Tin
Balance Lead

It used to be used for typesetting.  The antimony was used to harden it. A lot of casters used to cut it 50/50 with pure to make Hardball alloy.  It used to be much more widely available as scrap. I used to get it for less than $1/lb as few as 5 years ago. Some pieces still had ink on them.

I tend to start with cast lead data not for fear of leading but for over pressure.  That said my .44 Mag load is the max load listed in my spear manual for jacketed bullets using SNS 240gr SWC coated bullets.  There's no substantial leading or pressure signs in my super redhawk.  I use over the listed max load with 2400.

This is interesting. Thank you.

Yes.

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Lymans cast bullet handbook has more data

158 #358665

H110 14.4 - 15.9gr
==========================

160gr #358311

H110 15.8-16.5gr

2400 is great too.

http://www.darkcanyon.net/MyFriend_The357.htm

In my experience, commercial coated and homebrew powder coated work very well with magnum powders...no leading.

This right here is good info for beginning casters.

Also of note, some alloys used for wheel weights contain arsenic, which IIRC is why water quenching has a more pronounced effect on these alloys. It’s been a while since I read up on all this. It was more info than was really needed. I don’t cast much anymore though, and never used wheel weights.

Age hardening is also a thing and varies by alloy.  Also, straight linotype bullets may have been common when it was dirt cheap to get, but they’re much harder than they need to be. Hardball works just fine, and cut even more (with a little tin added) is sufficient for most uses.

In the future I would like to get into casting as well but not in the cards yet.  I am building a small mountain of scrap lead, ww's, and any lead I can get my hands on in my shed.

Start looking at cheap sources of tin now unless you like the idea of paying $15-20/lb for it.

“Britannia metal” is mostly tin.