Question about Model 3 DA .44 Russian

[twaits]

I have this S&W DA in .44 Russian that the cylinder throws by on occasion. I think it's specific to two of the chambers. I disassembled the gun and the action was quite gummed up with 130+ years of grime. So I gave it a good cleaning. The bolt and spring were really loaded up with crud. So I thought cleaning these would help. It still throws by. Is this because of wear on the bolt notches on the cylinder? Or is it the bolt itself? Would a stronger bolt spring make a difference?
Thank you!