[JohnK]

I wouldn't worry about it, Hodgdon lists 4.0gr as a max load but just using a magnum primer shouldn't increase your pressure much, if any.

If you're worried about it drop down to 3.5 gr and shoot away. As long as your gun will fire the magnum primers (they're often harder than standard) they should work just fine for you.

 

[JohnK]

You do know you can pull the bullets and reuse the components if something did go wrong, don't you? So you wouldn't have wasted the brass/primer/bullet/powder, just the time it took to assemble the rounds and pull them apart.

 

[JohnK]

No argument there! I had to pull apart 100 9mm rounds one time because they wouldn't cycle a Beretta. Max powder charge, powder was weighed as they were pulled just for some reason that batch of powder was way under power.

I wouldn't wish having to pull a bunch of rounds apart on anyone, but at least it's an option when you have to.

 

[JohnK]

That would have been a much more enjoyable solution Mike, unfortunately a 357 Blackhawk is still on the "want" list and not on the "have" list.