I had a good time with the 123s. I was able to get them going 2900 out of my 20" gas gun before I saw any real pressure signs. I decided that I probably shouldn't be pushing them that hard. I now use the 142 SMKs, but I have a small stock (maybe 100 or so) of the 123s left that I should burn up.

The 123s and 139s are a lot easier to acquire.

What powder are you using? (I ask this question a lot, just to satisfy my curiosity of what others are using)