Brewster20;
Good morning to you sir, hopefully this finds you well.
I'd not heard of buffers until we'd been running the first 10/22 at our house for two decades - during which time only the Good Lord knows how many bricks of Blasers went through it. We're within spitting distance of Washington and they used to come on sale for $9.99 a brick every other week or so..... ah those were indeed the days.
Before going further I should note that the stock pins still needed to be pushed out and carefully fitted back into place after all those rounds, suggesting strongly to me that there had been no measurable wear on the receiver. As well there was no visible wear on the stock steel pin and you couldn't "feel" any necking or wear on it either.
Anyway in the fullness of time I ended up making a perfectly good, inexpensive 10/22 into a bit of a money pit project - lets say the receiver is still original and so is the bolt handle - anyway the first buffer I installed was a "Yellow Jacket" brand which has worked flawlessly.
As an experiment I turned a Delrin rod down and tried it, but found that it wasn't as soft as the Yellow Jacket one and produced more vibration and bolt clatter, though certainly less than the stock steel pin.
We've subsequently used a "Tuffer Buffer" in a build on a 10/22 our eldest daughter did and found it to be excellent as well.
A quick check on the 'Net showed no results on Yellow Jacket anymore so perhaps they're not around - I'm not sure.
The buffers are, as noted by another poster, a polymer resin and not much more - though as I found out something as hard as Nylon or Delrin isn't as functional as a softer polymer.
Hopefully that was useful information for you or someone out there this morning. Good luck with your 10/22 whichever way you decide to go and all the best to you this spring.
Dwayne