I'm glad you have brought this up, Rich. Here's one man's perspective, for whatever it may be worth...
Years ago, when I built model airplanes, I was a member of an online forum not so different than this one (though the average maturity level was markedly lower...). The message board had specific sub-boards for sharing in-progress and finished models, each with specific intent and rules. If memory serves me right, they were as follows:
"In-Progress Pics" -- share your build as it progresses, ask for help/advice, weigh in with constructive criticism of others' builds, etc.
"Display Case" -- simply post your finished build and others are welcome to give attaboys and encouragement; a good place to celebrate the achievement, as Taylor said. Specific to building rifles, there can be a confidence deficit as a new guy when it comes to posting, and that confidence is built largely through positive feedback, at least initially. You could certainly PM a guy and ask him if you can share some thoughts, advice, etc, on his finished project; by virtue of going private, a newbie lacking confidence doesn't feel embarrassed when his mistakes are pointed out in front of others. Everyone responds differently. But, as Taylor also mentioned, one doesn't get better without honest, constructive feedback, hence...
"Critique Corner" -- similar to the "Display Case," but by posting your work there, you are okay with any/all constructive criticism/feedback in a public forum.
When I finished my most recent rifle, I wasn't really sure where to post it, in "Gun Building" or "Contemporary Longrifle Collecting." I wasn't really building the gun anymore, but as an amateur I sure as $#*! wasn't going to consider it a collectible, either! Maybe a dedicated sub-board or two would help?
There's a very human element to sharing your artistic pursuits and in a perfect world everyone would take and offer criticism well... but we all know the world isn't perfect. There's that quote about art not being the finished product but rather the feelings inspired by the journey... sometimes you just need to be able to share the feelings by posting your in-progress or finished project with other people who feel the same way.
Just food for thought!
- Tom