Before any concerns about charge, the simple act of doing so would release 100000000000000000 Joules of energy.

For scale, the largest nuclear weapon ever tested converted around 2300g of matter to energy[1].

Please don't do that :).

[1] https://faculty.etsu.edu/gardnerr/einstein/e_mc2.htm#:~:text....

If you could somehow do that without the 140 gigacoulombs of charge exploding violently before you got close, approximately this: https://youtu.be/YtCTzbh4mNQ?t=16

If you don’t invoke space magic to prevent the positrons from exploding even before they annihilate anything, and they are confined into a 0.1m radius ball, the charge density energy overwhelms the annihilation energy and the ball of positrons explode with a yield of ~1e33 J, which — without exaggeration — looks more like this: https://youtu.be/KNjWpSglUOY

Yes, assuming all those positrons started out in your stomach, the actual antimatter wouldn’t add significant energy in comparison. The charge balance stays the same when positrons and electrons collide. So, bigger boom than just an anti mater sandwich, not that you would notice the difference.

Relativity actually makes this worse as the electrons are limited to the speed of light but the charge can keep dumping ever more energy into them until their far enough apart.

Similar idea, just larger scale: https://what-if.xkcd.com/140/

Seems like a positron beam would be a sweet weapon in space.