Can I use magnum primers in .40sw, 9mm?

Should be fine, I plan to do it with mine. I would just start all over and work your way up with your load again.

Yes, you can use them.

No need to lower the powder charge unless you are already at a Max load level.

On the other hand, conventional reloading wisdom is to back off and work the load back up any time you change components.

This from an old thread:
http://www.thehighroad.org/showpost.php?p=8833086&postcount=1

rc

I just went through a thousand 9mm using mag primers... my charges are never close to max so I didn't change loads at all. They worked fine.

Just back off and work back up. When times are hard we gotta do what we gotta do. They'll all go bang.

Yepppers use them. Don't use near max loads.

Yes, but any time you change a component, it is always prudent to re-work the charge, and substituting with a magnum primer, would be mandatory in my opinion.

GS

edit: (in the .40, I'd be a bit more judicious with regard to downloading a bit)

I've done just this - using mag CCI - in my 9mm, as that's all I could find. If you are using a fairly robust modern pistol, I tend to not worry too much, with regard to reducing charges too much. I doubt very much it would take a standard pressure 9mm into even the '+P' level. I'm using a full published standard charge from the latest Alliant manual using Power Pistol, 115gr GoldDots, and the chrono shows only a few fps over the data. Shooting an old Star BM. Primers look fine, brass ejection about the same.

Yes, they'll work fine. Just don't start with a full house load. And experiment safely, remembering the reloaders caveat, "When you change anything, You change everything."

You can use small rifle primers too, that is as long as your pistol reliably sets them off as they're a touch harder than pistol primers. You would want to back off loads with those too, but I've done it in a pinch.

0to60 said:

Can I use magnum primers in these? Would I have to lower my powder charge a bit?

Click to expand...

YES, why not?

Just a note, Winchester Large Pistol Primers are rated for both standard and magnum use. Nowhere in any load data I have read is there a notation or warning to lower your charge weights when using WLP primers.

There's a few reasonsto back off a little when changing things. One, and the prominent school of reason you see playing out here, is due to safety. While this should always be of paramount concern, you're probably not going to bpow anything up as long as you weren't near max charge before the primer change. Two, and the reason for MY reloading efforts, is to achieve maximum accuracy out of my ammo. I have found that generally acurracy improves as I step up from starting loads, then reaches a sweet spot, then groups start to open up befoe I get to max. Most of my loads wind up around the middle of the scale, some below, some above, but I don't load any max charges and only one minimum on routine. Not because I'm afraid of max, just because they didn't shoot the tightest out of my gun. I would start over, or at least drop a little and work back up tomake sure I was preserving max accuracy. They might srill go "bang" but that aint my aim...pun intended. Your goals may be different, just my 2 bits.

-BunnMan

Magnum primers burn a little longer and a little hotter than standard primers, they will not create a nuclear explosion! (back to what I said about WLP primers above)

Did some tesing a while back

180 Gr truncated cone lead 4.8 Gr Power Pistol 1.085
STD Primer 888/ 860 AVG 875
MAG Primer 917 / 888 AVG 903

The 4.8 PP laod with mag primer is almost exactl the same as 5.0 Gr PP with a standard primer which averaged 905

JIM