I had done research on this before because I was in the same boat.
Magnum primers readily available for small & large pistol, but the normal ones sold out.
Depending on the manufacturer, some can add anywhere from 1000 to 5000 cup
increase in pressure depending on your load.
As stated above, if you are nowhere near max load, and your firing pin will strike them,
you shouldn't have any issues - just a little more FPS.
I think the magnum primers will also burn up all the powder - little cleaner firing.
I had done a batch of .45 acp with some unique and large pistol magnum primers.
If I remember right, I was about 1 gr under max load, so was not going to hit high pressures.
The rounds shot fine, no issues, no light primer strike, etc.
Rounds seemed a bit more 'snappy' for recoil - but that could've been me imagining...
For the most part - in a pistol, your main concern is not running a max load and light primer strikes.
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Edit: Found this article and 2nd link is primer pictures - very enlightening!
http://findarticles.com/p/articles/mi_m3197/is_n8_v34/ai_7903615/pg_3/?tag=content;col1
http://www.6mmbr.com/PrimerPix.html