Without the trace of arsenic, the lead will not harden when quenched.

Adding shot (which contains arsenic) to a favourite alloy mix of lead, antimony and tin 9rthat does not contain arsenic), will allow the mix to be hardened. It only takes a small amount of shot, say 1 pound in 10, or maybe even 20. You would have to experiment to find out precisely how much us needed.

Adjusting your ("wife's") oven temperature to just below the 'slump' temperature, then 'soaking' the bullets at that level (usually somewhere between 400F and 500F on the dial) for 1 1/2 hours, then dropping them into a bucket of cold water, will achieve the required hardening of the alloy.

This hardening is not immediate as when hardening steel.

The bullet's drop and bumping into each other should be cushioned on the bottom of the bucket with a folded towel.

The quenched bullets can then immediately be dried, sized and lubed. If left for 12 hours or more before sizing and lubricating, the bullets will re-softened by this 'work'.

If sized and lubed immediately after been dropped, they will attain the hardness dictated by the alloy and their temperature when quenched, in the 12 to 14 hour period.

Lead bullets, especially WW alloy which contains the requisite arsenic, may attain hardness up to brinel 32. Dead soft copper is 34 on the brinel scale IIRC.

Ross Seyfried used just such hardened WW bullets for a cape buffalo bull shot with his .50 Linebeau revolver. IIRC, it was a 440gr. bullet at some 1,450fps. Or perhaps a .45 with 340gr. at a similar velocity. Complete penetration, no bullet upset, just like a 'proper' jacketed solid.

Linotype is not suitable for hunting big OR dangerous game due to the brittle nature of that alloy - they break up on bones and even tissue if HP in design. Hardened bullets do not do this.