I am new to reloading, so please don't decapitate me for asking the question.

I have reloaded approximately 500 rds of 45ACP with good results using a Lee Pro1000, 6.3g of Hodgdon Longshot, CCI #300 LPP primers, and Berry's 230g FMJ RN bullets. I try to buy in bulk whenever I can, this is key to saving money and keeping the price per round down. I recently purchased 1000 LPP primers but they turned out to be magnum primers (CCI #350) and not regular LPP primers. The place that I bought them from won't take them back because they have a policy of not accepting reloading supplies back on returns, so I am stuck with them.

Here's the question: Can I use these instead of regular primers if I drop the powder load a half grain? Longshot is a medium burning powder, meaning it is not slow nor fast, but in the middle of the scale as powders go. For 45ACP firing a 230g FMJ round, will it make much of a difference?

Comments? Thoughts?