Great to see you up here Randy!
Yeah looking at the ETA 1256 spec sheet is showing nothing about the barrel material.Good question.
For what it’s worth though, I can pass along my limited 2 cents worth of experience with Moebius 8217 and Kluber P125.
I finally broke down and broke out the wallet to splurge on some Kluber a while back.Ouch! It was worth it though. I use it for both brass and steel barrels using stronger mainsprings. Its stronger braking attributes make it an excellent choice for stronger springs. For weaker springs I either use very little Kluber or go with 8217 due to rebanking concerns. I say ‘concerns’ as I’ve only heard that rebanking can be an issue but never actually experienced that problem using Klubers.
Not sure if that helps much Randy but again limited experience with it up to this point. Very happy to have it on the bench though and more or less think of it as a good addition to Moebius 8217 rather than a total replacement for it.
All the best my friend!!