In G1 the Transformers were shown to carry handheld weapons whenever their needed.
In later continuities, it's shown the Transformers can transform their hands into a weapon, like a blaster, sword, etc. Where do they come from? Their not visible in their robot or alt modes.
Some Transformers toys show the weapons becoming apart of the vehicle. For example Generations Red Alert's gun becomes an exhaust pipe. Some of the Masterpiece figures have areas where they can simply put their weapons away, in their back (in MP-10'S case) or their legs (Sunstreaker.) This it not shown in any of the animated shows.
Any theories?

 

Most weapons canonically will be stored within their bodies or dematerialize into energy or stored in subspace. The latter having been a fan theory is actually canon. Excess weapons, like excess mass, can be shunted into a pocket dimension until needed and often materialize as a burst of light as energy converts to matter.

 

Built-in holsters inside their legs, just like Robocop. Look on your shelf and almost every Transformer keeps its thighs intact between modes.

Well, except for MP Shockwave, but he turns into a gun.

 

Their prison purse?

I do much prefer it when the toys give you a place to put the weapons in their alt mode as having them lying around is annoying.

 

When it comes to external hand held weapons (not integrated like in the Prime series), I like to think of them having built in holster or storage areas for their weapons like the Robocop picture earlier. Prime had his rifle stored in his body in the first Dreamwave TF miniseries issue #5.

 

They are transported inside Optimus' trailer. When it disappears the weapons are left behind.

 

Bastard you stole joke

 

kind of varies sometimes they become part of the alt mode, other times their stored in the vehicle mode most toys now always seem to incorporate some type of weapon storage, or less common the guns are physically part of them and kind of transform in and out of the body as needed

 

I heard that Victory has a subspace storage pocket that some Transformers can store their weapons in, but since I haven't seen the show, I don't know how common this ability is.

 

Narnia

 

It happened once or twice in G1 and with some regularity in Headmasters and Super-God Masterforce. What you heard about Victory is absolutely correct. Literally every character in the show just had their weapons appear in a flash of light when they needed them. (Star Saber's use of this was particularly prominent, due to it being part of his stock transformation sequence, which showed up EVERY EPISODE.) Otherwise, it doesn't seem to be very common.

 

Subspace similar to Rom Space Knight (Marvel)

 

I always thought it was holstered or back pack style as a pic above like robocop or Kratos style.

 

Weapons are either on them or appear out of a dimension pocket

 

Really big zip lock bags.

As mentioned, yes, but it goes one step further, in they are too low on energy, the weapons can't fire and will even disappear on them. A useful plot device that saved Star Saber when he was getting beaten on by Deathsaurus in an episode; as Deathsaurus had just provided energy to freeing his fortress and didn't have enough power to last the fight.

 

You know....( ͡° ͜ʖ ͡°)

 

Hammerspace.

 

Subspace highway inside Scott Pilgrim's mind. It's so vast and empty. Everyone stores stuff there.

 

So, the answer is built-in-storage or subspace energy creation (or a combination of both in the instance of Optimus's energy axe and Megatron's energy mace), depending on your continuity.

Both are better than Gobots laser fists.

 

Either subspace pockets (less realistic, easier to animate) or they are made out of "Transformium" (more realistic, harder to animate). Depends on the continuity.