Brain Fart

[Dave328]

I'm about to FINALLY get my Hornady LAL set up and run off some .38 and .357. My brain fart concerns using magnum primers with non-magnum primer load data. IIRC, isn't the rule to cut the charge by 0.5 gr? I can't find my old load notebook, and if I tear my old reloading room up looking for it....well there goes another Saturday! Anybody know for sure offhand? Beuller?

 

[Storm52]

It depends on your powder. Slow burning, then MP works fine.

 

[The_Shadow]

Are you at a MAX load? If not the primer may not make a difference
What powder are you using?
Generally you can cut down the charge weight by 1.0 to 0.5 grain and be OK also....

 

[Dave328]

I use mainly W231 for .38. Not at max load. My .38's are mainly paper punchers so I load light to save powder. For example, 125gr LRN calls for a starting of 3.8 of W231 (max is 4.8gr). If I use a magnum primer, I should be safe to keep the 3.8gr or maybe even drop it a bit, ( to save some powder over several hundred rounds) right? I still haven't found my book, but I now remember I did cut my max load by 0.5 gr in .38 when using a magnum primer.

 

[noylj]

The rule is to use standard primers if the load data calls for them and magnum if the load data calls for them.
If you change any component, you are to go back to the starting load and re-work the load.
There is no "rule" about switching primers other than above.
Now, if you asked about a 5% reduction, that might be reasonable in most conditions.