using cci 550 instead of cci 500

Pinecone · Jan 8, 2019

The bottom line is, anytime you change a component, reduce the charge and work back up, looking for pressure signs.

The change may make no difference, or it might take a safe load and push it into dangerous ranges of pressure.

alucard0822 · Jan 8, 2019

Pinecone said:
The bottom line is, anytime you change a component, reduce the charge and work back up, looking for pressure signs.

The change may make no difference, or it might take a safe load and push it into dangerous ranges of pressure.

Definitely, although IMO it is more dangerous to substitute standard primers for magnum data than the other way around. Magnums may or may not increase pressure, will probably get a warning or two from brass, and even then probably wouldn't get above proof-load pressures unless the magnums were a direct swap for data already at max pressure using relatively sensitive powder. With standard primers in place of magnums, some really slow powders like H110 claim a partial ignition can smolder, and burn out or light the powder all at once, instead of a flame propagating through the charge as it should, causing a big pressure spike, or hang-fires and squibs. Haven't experienced that, and haven't seen conclusive evidence from anyone that has, but it's enough for powder companies to issue warnings for standard primers, and even using reduced charges.

Magnumite · Jan 8, 2019

I loaded 30-30 and got lower velocities using magnum primers and 748 powder. Not a big difference but enough to make it observable.

During the 2012 - 14 can't find 'em times, I couldn't find any standard small pistol primers for 9mm. I did substitute 550's for those primers using Bullseye. I was a bit nervous since Bullseye is a fast burner. I did back the charge off and ended up at nearly the same powder charge...which was not a maximum charge. YMMV

Seabee · Jan 8, 2019

Doctor_M said:
That's about the size of it for MDS.

By the way, add my, "I wouldn't if it were me" to the list.

Roll them dice

tdt91 · Jan 8, 2019

I've done it without issue.

using cci 550 instead of cci 500

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