So I was fiddling with my stock and ended up blasting my buffer retainer across the basement, probably never to be found. Is there any local shops with small parts like that or am I out of business until I can order it online?

I couldn't find any place locally when i lost the same pieces. I ended up ordering from brownells and ordered a few extras of the retainer, spring, firing pin, carrier key, extractor, take down pin springs, gas tube pin, ect. Good to have that stuff around.

As luck would have it, I found the part, sitting on TOP of my foundation wall under the 2x12 skirt (!!!). But still, if anybody knows a source it would be good.

 

I've had excellent service from operationparts.com which is where I would have purchased if I didn't find this stupid thing.

I've ordered small AR bits from weaponparts.com. There's also several places that sell "most usually lost/worn out" AR parts kits.

Check out Palmetto State Armory for individual AR parts. I'm very happy so far with the lower build kit I purchased from them. Good quality, fast shipping, good prices. They sell various kits and individual parts.

 

I had a Bolt Catch Detent fly off on my during my build. Was extremely frustrating b/c the "spare parts kit" I had on hand didn't have that part.

 

Fortunately , like you I found it after 20 minutes of frustrated searching!