Can I substitute magnum primers instead of regular primers?

[teddy12b]

I'm reloading in 9mm and have a bunch of small pistol magnum primers.  I'd like to use them up, but the reloading books I have are all saying to use a regular primer.  It doens't seem like I could just switch the two primers out without added pressure.  Is this something where I have to start low and work my way back up all over again now? 

I'd like any advice any of you have to share on this.

[Scibaer]

yes, if you change any component , you need to start over and work back up.
you can use mag primers in 9mm loads, but you need to start from the lowest charge and work up.
you have it right, mag primers can / will increase the operating pressures.

you may find that there is no noticeable difference in point of aim, or felt recoil but the chamber pressure may, could or will be higher. thats something you cant measure without expensive and elaborate equipment. so work safe and look for any excessive pressure indicators on the extracted cases.

[Drilling Man]

  I'm with the "don't do it" camp.  Personally, i wouldn't even try working up to a load with the mag. primers, in a small capacity case like that...

  DM

[mdi]

yes, if you change any component , you need to start over and work back up.
you can use mag primers in 9mm loads, but you need to start from the lowest charge and work up.
you have it right, mag primers can / will increase the operating pressures.

you may find that there is no noticeable difference in point of aim, or felt recoil but the chamber pressure may, could or will be higher. thats something you cant measure without expensive and elaborate equipment. so work safe and look for any excessive pressure indicators on the extracted cases.

I agree.
If you only have a small quantity of magnum primers it prolly isn't worth the "trouble" of working up a load for them. But, if you are a confirmed tinkerer/experimenter, like I am, working up a load with mag. primers may be worth the time for future refrence...

[teddy12b]

Well I normally load my 9mm rounds at normal levels.  I can't imagine these would get pushed from normal levels to over +p levels of pressure, but I don't know that for certain so I won't push my luck.

[Scibaer]

no, using the mag primers will not run the pressure over a +P level.
i have replaced small pistol with small rifle and lg pistol with lg rifle and vice-versa in working up some loads, with no dangerous results.
i have used bullets cast for .380's in 38spl , 357 mag , 9mm bullets in .380's , .357 mag and other swaps like that without incident either.
if your careful and look at the specs carefully and study the loads given, you can create something fun and usable ,that is safe.

its just my opinion, but i think it makes you a better hand loader. you teach yourself an understanding of whats going on in making up a specific cartridge.
and i got a better understanding of each component and thier uses and limitations.
as an example i took a .357 mag case, used a 90 grain cast bullet for a .380 ( .355 dia ) and set it on 7 grains of titegroup, i cut the case back so there was just enough room for the powder and bullet. i got fair results with  small pistol primers, but when i switched to small mag primers it really preformed well.
it makes a great gallery load.
but that's me, i find tinkering and experimenting with loads fun. but being careful and safe is paramount. only do what you feel comfortable with
glenn

[BCB]

I somehow ended up with 5000+ CCI-550 primers…

All, or most of the loading data calls for small primers or CCI-500 in the 38 Special and lighter loads in the 357 Magnum depending on powder charge/type…

I use the CCI-550’s and don’t look back…

I have always used magnum primers in all applications regardless of handgun or rifle even if it calls for regular primers, which are use sometimes also…

If you look at relative “power” of all the primers that have been compared in magazines such as Handloader, some of the regular primers produce more velocity with the same load than the counterpart primer in the magnum designation…

But one must not be an idiot and start with maximum stuff or just “blindly” prime away…

The comparison charts are the source of reference and decision making…

Good-luck…BCB

[38MAN]

Last year when primers could not be found at any price here in East Tennessee I bought 2000 Winchester small pistol magnum primers. I load .38 special rounds mostly. I loaded 100 rounds each with the standard and the magnum primers. I used 4.4 grains of 231 power behind a 125 grain hp. There was not enough difference that I could measure by recoil or feel. I inspected my cases, didn't see any signs of excessive pressure or notice any difference when I deprimed and resized. Performance wise I didn't notice any change either. All where on the paper and grouped about the same. I don't load hot loads. You may not want to use them if you like hot loads. Plus, I'm not sure this data would apply to a 9MM. Hope this helps.

38Man