huge topic! There are many things you need to know before buying reloads at a Gun Show. You don't know the guy or who even did the work, how careful.Less he was and exactlly what type of bullets you'll get.
There are a few very reputable "reload sellers" at the shows, they have their own tables, multiple calibers and of course a business card to contact them should you have questions, Yea it could all be phoney but the "real: guys put a pretty good front up! I have bought like this and have beenpleased with reasonable costs.
I much prefer to buy from friends and pay a little extra and even help out if I can to learn more!
In reloading it is possible to make mistakes but it's best to have at least 2 people check powder levels and make spot inspections.
I stick with 158 gr bullets, nothing tricky.
It's still chancy because mistakes caaan happen. it's best to spot check all of the proces!
ZVP