I have loaded a lot 230 gr FMJ for my .45, and want to try to duplicate my hardball load with a 230 gr LRN.

My current hardball load is a Hornady 230 gr FMJ, 5.6-5.7 gr W231, 1.26 AOL.

I get my lead bullets from a local caster, he recommended 5.0 gr W231. The bullets are shaped a little differently, so my AOL ends up at 1.25, a little shorter.

My question is: how close can I get to my hardball load (in velocity/recoil), and not have to change my sites when switching between FMJ and lead?

In my revolvers I've noticed the POI of jacketed and lead bullets to be very different. I think lead was shooting several inches higher than jacketed at 25 yards.

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Common sense isn't so common.

YOU SHOULD BE ABLE TO GET A VERY CLOSE LOAD, I HAVE BEEN SHOOTING LEAD BULLETS FOR 30 SOMETHING YEARS, AND IS JUST ABOUT ALL I SHOOT NOW SINCE RETIREMENT I HAVE MORE TIME TO CAST UP MY OWN.

Well if you don't have access to a chronograph a general rule of thumb is the hotter the load, the lower it'll print. Sounds like your current load is plenty hot, Winchester shows 5.3grs as max with a 230gr. Lead will almost always shoot faster than jacketed per givien load. I'd load up a few lead with 4.8, 5.0 and 5.2 and see where they print and go from there.

+1 on the above. Lead causes less friction in the barrel and will exit a tad bit faster than a jacket type of the same bearing surface.
I mostly shoot cast and have no regrets. All my barrels get smoother and will never wear out.
Just be sure the cast bullet is the right diameter. .001-.002 over groove should do just fine. You do NOT need any Hard cast bullet for the low pressure 45ACP develops. I cast my 45 and most other pistol bullets in 50-50 mix.. WW-Pure.