1 Shakespeare: These were supposed to be prop guns! What happened?!
2 Mercutio: Do you know how hard it is to find prop 16th century guns? I ended up buying some genuine antique 16th century guns.
3 Shakespeare: You didn’t think to check if they were still loaded with genuine 16th century ammunition?
4 Mercutio: On the bright side, the bullet won’t look suspicious.
4 Shakespeare: I think the bullet hole might.

There's a time travel roleplaying game setting in GURPS Time Travel which has a variable chance that equipment will successfully be able to be sent into the past with the time agent protagonists. If the equipment is very modern and didn't exist in the time period being travelled to, there's virtually no chance of being able to send it back in time. If the equipment did exist in the past time period, but you have a modern reproduction, then it's more likely to be sent back okay, but still not a high chance. If the equipment is made of material that actually existed in the past time period, but reworked, then it has a high chance of travelling back. But the best chance of sending equipment back is to have a genuine antique that existed as it is in the past time period.

So in this setting, if you travel to the 16th century and want a weapon, your best bet is to locate a genuine antique from the period and take that back with you. Trying to take a modern gun will almost certainly fail.