I recently purchased jacketed 158gr bullets to use in my .357 magnum.  I also plan to be using them in my .38 cases loaded to .38 pressures.  Unfortunately my reloading books do not have data for my powder type (Bullseye) in .38 pressures with 158gr jacketed bullets.  I was thinking of using the data for 158gr lead .38 special loads with with jacketed bullets.  It is my understanding that lead loads are typically lower pressure than jacketed loads and should be safe to use in this instance.  Is there a flaw in my logic anywhere?  Thanks!

You need to google it... thats probably the most popular 357mag/38spl load ever made.... 158gr LSWC.

I'd imagine something in the 3-4 gr. range would be about right with it though.  

What reloading manual are you using that it doesn't tell you a load for 158gr cast bullets?  

MIke.

You misunderstand.  I have loads for 158gr lead loads...just not jacketed loads.  Currently all I have are jacketed 158gr bullets.  Basically I am planning on loading the jacketed rounds with the data for lead loads and I was wondering if this could in any way be a problem.

Who makes the bullets?  If it's one of the major makers (Hornady, Speer, etc.) check their reloading manual(s).

BTW, you should be OK shooting at "lead" load levels... but if the loads are too light, you'll end up with a bullet stuck in the bore.

Thanks for the info.  I know that Bullseye isn't the best for everything, but I'm currently loading 9mm and 45 as well.  As I use bullseye in both these loads I'm just trying to keep things simple for now.

I realise that folks want to keep things simple but if you are going to take the time to reload you might as well have more than one bottle of powder on the shelf.
Keep the cover on the can when not in use and under reasonable conditions and it will last for a good many years.