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Awesome, I'll bear it in mind - thanks a lot. I'd definitely recommend joining our Discord server (link at the top of the page), as we use it a lot to coordinate editing and whatnot!
The page is unlocked now so you should be free to edit yourself now. For what it's worth, the gun has only ever appeared in one panel of the comic so I don't expect there to be any other sources to really list. As far as I'm aware, the page more-or-less covers all the available info.
I've updated the page to reflect that there is no canon connection between the Colt and Petra's gun. I'll unlock the page now so if you do wish to flesh it out with a fuller description (IE the feed that you mentioned), feel free to go ahead. Just remember nothing that isn't stated or shown in the source material can be put on the page. For example, putting the ammunition type down would not be allowed, as nothing has ever stated its ammo type.
Truth be told, that information should be removed entirely too, which I'm going to do in a second. However, note that it does say "based on the", it doesn't say it is a Colt. That's a fairly important distinction, but even then you're right that that info shouldn't be there either.
As an example, take a look at Type-25 spiker. More or less every statement on the page is followed by a source of some canon piece of media in the series, where possible. It's definitely a standard to have a look at if considering helping out with weapon related articles!
As much as that may be true, we don't have information on articles based on assumption, only what is stated in canon or by the developers/ writers directly. Assumptions (even logical or small ones) have, in the past, caused major issues so we have a fairly hardline stance on it. Sorry.