I have been trying it. My goal is to never have to buy jacketed again.
I am about 1/2 way through my load development. I keep getting side tracked with new guns to play with.
The cast in a 223 AR is a tough nut to crack. Nothing like finding a good cast load out of my 300 Black out AR. That took about two range trips.
But it is crackable, Just need to be more patient and tapper your expectations.
Your dealing with a semi auto with a fast twist that requires a certain amount of gas pressure to operate the action reliably.
Getting a load that will run slow enough to give good accuracy is not hard.
Getting a load that will give the gas pressure you need is not hard.
Getting both those numbers at the same time
Thats the rub.
I found you can get a load to work sort of ok out to 50 yards.
Trying them at 100 your looking at paper plate accuracy.
Optimally your trying to hit a magic window of 2000 fps or less.( depending on twist rate) 1-9 is common. 1-7 twist would be much harder. 1-12 or 14 would be Nirvana if I could find one cheap enough. Spending 4 or 500 on a 1-14 barrel might make the cost savings of switching to lead a moot point.
I have a couple decent loads for 50 yards. using 55gr and 60 gr cast.
I have a new mold that cast at 75gr. I will spend some quality time with that one this fall. Should be able to slow it down enough to stabilize at 100 yards.
Or I may go the other way and cast them very hard and powder coat and zip them real fast and see what happens. Will see....
It can be done, Others have done it and are happy with the results.
But this platform follows the rules of each gun being different, That is true here more so than any other platform.
I really think an adjustable gas block would help allot. Find a good shooter, then adjust the gas block to get the gas you need. Hmm maybe... Problem is most I see are to tune the gas down. I want to tune the gas up. I may make my own.