Thanks guys! On with the list:
#23: Guns and WeaponryAs a teacher in Japan, I've learnt two vital pieces of lifestyle advice: never eat anything that you've only seen so far in zoos and never hand a child a weapon (toy or real) unless your end goal is a bloody nose and tears before bedtime. There's an dark, unleashable spirit inside even the politest of children. A spirit that loves saying "Pew Pew Pew".
Despite the faction symbol being based on Soundwave's face, if you say the word "Decepticon" to the average man in the street, one robot face will leap to mind:

"Buckethead. No wait, Megatron."
Yep, the almightly leader of the 'Cons turns into a Walther P-38. The bad guy turning into a gun is as plentiful a source of jokes as the age old "Daleks vs. Stairs" debate, but the truth is he's a pretty damn cool-looking gun.
"Silly Megatron, being a gun to a knife fight."
Unfortunately, though he had lots of play features his robot mode was rather lacking. Or should I say "not lacking at all, in a certain department"?

"It's time for the interactive portion! Roll a die now! If the number is 1 or 2, the joke is "Now that's what I call a fire crotch!" If the number is 3 or 4, the joke is "I have an itchy trigger, Prime!" If the number is 5 or 6, the joke is "Sorry, I went off accidentally!""
The next figure that'll never ever ever be reissued in Austrlia is Shockwave:

"Okay Hasbro, Simon says: Don't reissue Shockwave. Okay, Simon says......: Don't reissue Shockwave. Alright, well done. Okay....don't reissue Shockwave! Dammit Hasbro, you keep
losing!!"
Shockwave was another figure introduced to Transformers despite not fitting in with the whole cars, robots and devices theme of year one. Someone, probably good ol' Uncle Bob decided that if Shockwave was going to be a futuristic raygun, he may as well be a huge, tanker-truck-sized raygun.

Pictured: the perfect disguise.
I don't have much to say about this figure, except that due to degradation of his rubber parts I advice that if you have this toy you may want to store him in a safe place, like the surface of the moon.
The real meat and bones of weapon bots would come a few years later with: THE TARGETMASTERS!

"Hello Optimus, this is Autobot R&D. We come up with a new idea: guns with minds of their own."
"Err....no."
The Targetmasters were an amazing idea: We all loved figures that turned into things, we all loved having guns for the figures, the only way we could love it more is if the guns transformed too, right? As it turned out, the idea was better than the execution. The figures had zero articulation (well, some of them could sort of sit down) and they had little to do in robot/Nebulan mode except just stand around. Except for Nightstick: The Return:

"Vector Prime's going as Cloud, so I said I'd go as Barrett."
The backstory of the Targetmasters is pretty interesting: in the cartoon they were guerilla fighters paired with the Autobots to lend both their combat experience and their sharpshooting skills, and in the comic, poor Budiansky was being overworked by Marvel until his brains started melting.
Next up were the ActionMasters (or however you want to parse it). Unable to transform themselves, they each came with a skateboard, animal, backpack or Cuisinart that could transform into a comedically oversized cannon.

"Hello Optimus, this is Autobot R&D. We come up with a new idea: Transormers that
don't transform."
"I'm cutting your grant. You know that, right?"
There was no news on the whole gunformer thing for a while, possibly due to legal issues. But that won't stop the Japanese, oh no.

"You're probably wondering if my penguin pooped five times or six. In all the excitement I kinda lost count myself."
Yep, the Japanese-original Beast Wars figures often had some kind of third mode, many of which made awkward cannons, artillery weapons and handhand implements of death. If anyone asks why I love Japanese Beast Wars so much, I ask them where else one can see a giraffe dual-wielding a penguin and a rabbit.
The Unicron Trilogy went back to the Targetmaster idea years later with their Minicons, but expanded it to swords:
If anyone has a picture of Star Saber holding the Starsaber, please don't share. There's only so much awesomeness my brain can handle.
And they also used some regular Targetmasters too:

"Guess what! You're
fired!"
"Yeah, it wasn't funny the first six times."
With the Classics series, Megatron made his first return to gunness (not Guinness) in years. Unfortunately, safety laws led to the so-called Nerf Megatron:
"Adults are always telling us we can be anything we want to be. But that's bullcrap! There's hundreds of things I can't be, for example: An alligator, a tank, a jet-plane-Batmobile thing, a car, a dragon, another tank..."
And then Henkei did it better (that's a sentence you may be hearing a lot in this list):

Pictured: a totally convincing gun.
Although it has its enemies, I love the Classics/Henkei mold. It may be a shellformer, but it's nice and well proportioned, and the gun is charmingly chunky.
I'll finish this entry on a high:
I'll admit, two decades and a 100+ dollar toy is what it takes to stop me making crotch jokes. Take note, Hasbro.

"Well paint me orange and ship me to Australia!"
The Megatron MP figure is utterly awesome. Most people probably put him in his slightly spindly robot mode but to me, happiness is a wrm, distinctly oversized gun. Coming with Kremzeek helped.
Next time, I'll be covering another beast mode. And I'll give you a hint, it's not rats.
"Nyeeeeaaaah! BROOKLYN RAGE!"