Bullet hardness is sooooooo over rated!!!!

Clip on wheel weights since the 80's has been around 10bhn to 12bhn and countless 1,000,000's of cast bullets cast from them have been put down range without any leading.

I've used nothing more than range lead/hill pickins/berm lead for decades and it normally runs 8bhn to 10bhn air cooled and around 14bhn water cooled. Never had a problem with full house loads in the 357's or 44mags. But as others have already stated, fit is king & excellent quality lube is queen.

Lube is often overlooked, when I load pistol bullets I like to use a soft lube with a high ratio of grease to bee's wax content. The lube will actually act like a gasket aiding in sealing the cylinders/bores along with protecting the bores. For rifles I'll use a harder lube that has a higher ratio of wax than the pistol lube.

Some common alloys from years ago.

Lyman #1 is a 10 to 1 lead/tin ratio ='s 12bhn. They recommended this for all their bullets, rifle, pistol, etc.

Keith used to use 16 to 1 lead/tin for his go-to alloy for testing pistol bullets and hunting bullets.

I've always used a simple formula of:
700fps ='s 7bhn
800fps ='s 8bhn
900fps ='s 9bhn
1000fps ='s 10bhn
1100fps ='s 11bhn
1200fps ='s 12bhn
ETC.

Never got in much trouble with those #'s unless I use the wrong powder for what I was trying to do.

Hence:
Fast burning powders ='s target loads
medium burning powders ='s p+ low pressure loads or plinking loads for high pressure calibers
low burning powders ='s heavy mag loads, max high pressure calibers.

I've been shooting allot of coated bullets lately (300# of cast/coated bullets) and they are the cat's meow!!!! Been casting/shooting lead since the 80's and the coated bullets are the way to go.

Extremely accurate and clean to shoot.
1 alloy works for bullets being shot from 600fps to 2300fps.
No more lubes.
Coated bullets are softer (heating the coating to activate/cure it anneals the lead alloy) allowing then to obturate better that hard cast lead bullets sealing different sized bore better.

I'd try some coated bullets 1st.