"The Second Amendment gives you the right to bear modern arms, just as the First Amendment gave me the right to make this poster on a computer instead of an oil painting."
"The Right to Keep and Bear Arms includes modern arms, just like Freedom of Speech includes telephones and email."
"The only 'cold, dead hands' will be the ones that try to take this."
"A musket was the state of the art personal firearm for its time. We must accept nothing less now."
"You will not steal my preciousssssss...." Sorry. An LOTR joke was mandatory.
"I know that he meant well, but I like this one better."
Feel free to use any or all of these. Tweak and/or correct as you see fit.