Casting soft points is not a 'silly' venture, if you need them for hunting. It isn't as simple as casting pure lead for the nose, and hard for the base.

Usually the nose must be a lead/tin ratio, up to 10:1 (to withstand higher pressures without slumping) and the base, a lead, antimony, tin alloy. Thus, the bullet can be heat treated to further harden the base, without hardening the nose. The straight lead/tin nose mix won't harden due to the lack of arsnic in it's mix. The WW/lead/tin base (#2 alloy) will harden further (arsnic in WW), but a straight WW alloy base can become even harder than if tin is added (which addition softens the mix).

Verl Smith's Jacketed Performance With Cast Bullets shows why and how.

I've done soft noses for the 44 mag. but not for rifle bullets. It can be successful and/or painful to do. It's certainly picky casting. The nose cast ladle must hold exactly the right amount and no more.

Once the lead temperatures are correct, the 'weld' is virtualy impossible to see, until oxidation makes it clear due to colour differences.

Soft nose slumping (bullets becoming wad cutters) can be a problem with higher speed, high pressure loads.

The Lyman #3589 is a super hunting bullet as it is, perhaps outdone only if it had a flat nose instead of round.

An alternative to casting in moulds.

It is easier to cast lead cores into .30 MI Carbine brass to make .358 bullets, or lead cores into .223 brass or 3/8" pipe to make .375" bullets, than to make soft nose bullets in a bullet mould. The jacketed bullets thus created become very cheap (range pickups) and useful for the full range of speeds and game available in that rifle. The .223 brass needs to be annealed then sized to .375" before being turned into a bullet. Both are then shortened/trimmed to whatever length you desire. .375" bullets can be made to well over 350gr. and .358's easily to 300gr. using ctg. brass - or whatever length/weight you want.

It's an interesting alternative to casting.