What limitations are there on prop weapons at a con?
This depends on the convention, some cons are very strict and have restrictions on size while other cons only check if it is dangerous. No convention will allow you to carry a prop that is illegal in your state/province. The convention’s website should include what they will and will not allow at the convention. If you would like clarification then you can email them or ask on the convention’s forums. Props that are normally not allowed at cons, such as a sharpened metal sword, could be used for photoshoots. However, make sure to check that your photoshoot location is okay with such things, and make sure the other people in the location know that they are props.