Well don't be so sure. You are probably right, but we don't know for sure what has transpired in the past 8 months (or do we?), I don't at least. It's not inconceivable to think that in the USA one might stumble upon a household or two with a few thousand rounds of ammo. Especially if it's something small caliber like .22 or 9mm. You could fit 2000 rounds of either of those easily into a fanny pack (Ok maybe not, but a kids back pack).
As for the Marvin the Martian ray gun (LOL!), it looks like a home made suppressor to me. Check em out on Youtube, there is plenty of ways to quiet a small caliber hand gun with home made materials. Also the fact that Rick's hand gun suppressor looked legit lead me to believe they stumbled upon some weapons somewhere. It looked like Sophia's mom had an AK-48 or something as well lol.
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