I’ve been buying/gathering spare parts for all of my builds, even complete BCGs when they are available. Items like bolts, ejectors, gas rings, o-rings, pins, springs, etc. I know have a box full of small part bags.
How do you folks store your spares? I’m getting to the point where I’ve ordered items I already have.
well for most of my small part storages, i like to use fishing tackle boxes. Academy has a great selection of translucent / clear fishing box containers that are water tight, have configurable compartments, and you can even label them if your ocd kicks in. i have these for my ar’s my 1911s and my glocks… they work real real well for me your milage may vary.
I agree with @GamecockOperator. Easy to use.
GCO has the best suggestion. I just use a couple of clear plastic small to medium sized bins from Lowes. They stack easily on top of each other on a shelf.
I use these from Harbor Freight. SKU 93928, 62778
Here in Nevada, you rarely need to worry about rust and corrosion, but I’m starting to coat parts with a layer of grease (or Frog Lube). I like the idea of putting them in parts storage cases/tackle boxes, but I’ve had mass corrosion when boxes got wet without me knowing right away. I’m probably rambling on, but I’m just trying to say: Watch where you store these important replacement parts. 
maybe something like this for rust prevention
Flambeau Zerust Max Series Tuff Tainer 3003ZM - Tackle Warehouse
I worked (professionally) with the M-16, the A-1, A-2, the A-3 and the M-4 for over 40 years. Rarely ever needed a replacement part. For me stock piling spare parts is not worth it.
The exception is my KS-47 which has a reliable reputation for broken extractors…. For that gun….and for that part only, I have a spare bolt & 2 extractors stowed in the pistol grip. I love that gun so much……that if it does fail…. I want to be able to swap out the broken part and keep the “fun” going.
same for the KS-47. I was able to FINALLY get a complete BCG for it.
I like to store my spare parts in new guns.
Because every time I decide to go through my parts bins and boxes, I realize I have enough to build at least one new gun. And then I order more spare parts to backfill the parts I just used.
It’s a vicious cycle.
very similar idea super predator. are those water tight? i like the tackle ones that are water tight. but thats again more of my ocd.
@james_the_second thats it. the exact cycle i have going on with my various tackle boxes. its true its vicious, but its fun too…
Just remembered about anti-rust storage bags:
https://www.zerustproducts.com/products/electronics-tools-parts/multipurpose-vci-poly-bag/
There is a dropdown menu for various sizes including 3x5, 4x6, 6x8, 9x12, 12x18, and a few more. They also have another section for rifle/gun storage bags. Zerust says they’re good for 5 years.
Unfortunately, no. Not watertight. And seeing how humid it is here, it would be beneficial to have that feature.
I actually keep one of these stocked for when i go to competitions. Learned it from another guy there. Keep parts ready to go. If something breaks (and it will), you have all the spares you need, labeled, in an easy to carry package.
Moisture & Humidity are the ? of all metal storage routines.
In a bag, indoors, is a good place to start.
Rice makes a decent desiccant. Or you could buy desiccant pouches and store those with your metal parts.
Or if you’re part hoarder, you might have 100 desiccant pouches that you saved over the years from vitamin bottles etc. They can be recycled & obviously they need to be dried out. I recommend the dashboard of your car, in the sun, to get them to a Super Dry state.
Second vote for Walmart tackleboxes. I keep all my tools and parts in mine. Easy to organize, plenty of room.
A small shot of some light oil in each compartment occasionally goes a long way toward rust-prevention of small steel parts.
Ima jus’ Sayin’.
yeah, thats what steered me to the tackle containers that are water tight. the ones i run with are like this one Plano Waterproof Tackle utility box there are many different sized ones and this way i can configure them to hold what i want per task. be it lower parts group boxes, bolt boxes, glock parts boxes, or 1911 boxes… it all goes well. I have one even setup for 1911 spare grips cause i have a variety of those too i’d like to swap out on occasion. of course in your situation a smaller one with just the bare necessity would work well, like the ones i use for my glock small parts that way you can transport it in a small and easy carry package.
computer and electronic boxes is where i get mine from. 
and they are huge if you get them out of server boxes.
I use these
Tactix 320020 Hardware & Parts… https://www.amazon.com/dp/B008VOGV0A?ref=ppx_pop_mob_ap_share
I don’t have a whole lot to add here given everything that’s been said by other posters, but I will say two things.
I’d recommend using paper bags because they’re breathable and if you use plastic boxes and any moisture happens to get in there, the parts will rust unless they’ve been oiled.
Also, when OP says, “I’m getting to the point where I’ve ordered items I already have,” I’ve had that same problem a few times.
My recommendation on this last point is to create a written inventory of what you have and update it as you use the parts or buy new parts. Personally, I’m putting mine on the computer so that it’s easily text-searchable. If you’re worried about privacy, don’t keep it in the cloud, just keep it resident on your PC. I keep mine in the cloud (Google Docs) so it’s not only accessible on my PC, but I can even access it for my phone when I’m at the gun store. I think it’s a really great way to inventory what you have. Actually, I use this system for more than just my gun parts, but for all of my 20 to 30 totes in my garage so that I know what tools and testing devices I have.
The list - I started that for my reloading components as well. It was getting difficult to keep up with bullets and shell holders.