I wrote this a loooooooong time ago,...
I wrote this a long time ago and though it is quite long, it is still very good information. It discusses both the readable direction and the spline/pad length, as well as transition.
http://web.archive.org/web/200303040...rabarrels.html
You can also go back thru Lane's Tips page (hat's off to Lane) and see what the early days of CSP were like - it was unique. Lots of great info there. Here's the link (and you might want to save it);
http://web.archive.org/web/200302022...com/lanestips/
If you are looking for a good WRA barrel, take your time. You may have to get a little bit creative, like I have seen some really nice barrels for sale recently, but you have to buy the entire rifle to get it. Often these are priced rather attractively given what you get with them (which is, a whole 'nother rifle!). The hard part for me is then selling off the excess parts which those who know me, know that I can never really manage to declare much of anything as 'excess' ... (grin)).
That is pretty much correct.
Below 125,000 everything 'seems' to be oprod readable and long spline/pad. After that the direction of print is both directions. Shorter pads and splines 'seem' to begin transitioning in around the change in contract or right around the 1.2 million mark. As with all almost all the earlier parts at WRA, they can show up at random on later rifles. With regard to these earlier profile barrels, while they may be less common on the midwar rifles, they do show up all the way thru production and quite a few have even been seen at the very end on Win-13's.
The earliest data is terribly thin, but that is basically what the observations (of many) support to this point.