I had reason to talk to Royce & order a couple OB1 partials a couple weeks ago, and I asked him if he had the break shaft available - 5/16-14 piloted - .840 joint black collar.
He had them, and I ordered one.
I've used it on one of my X Breakers (Samsara made).
The shaft has a good bit heavier taper than an OB1, and is 13mm diameter. The taper is more the conical/European type - sort of a really beefed up OB2. The hit is good & stiff. You can really lay into it, but retain good accuracy & minimal deflection characteristics. I can feel the shaft "giving up" more (only moderately more), flexurally, than my X Breaker shafts when I use heavy break power, but then the XB shafts really are monsters. I tend to stay to the middle of the cue ball for power breaking, and my consistency is pretty good, so I haven't got a firm handle on how much accuracy increase there is. But I'm a believer in OB1 shafts, so I think it could be worth chasing - especially for anyone with a less refined power break stroke. (Not that I'm all that...) Have to say, I haven't replaced my XB shaft w/ G10 tip on a full time basis as yet - largely because I haven't invested enough time into comparing jump capabilities of the OB break shaft. Royce makes no bones that, being a shaft intended to maximize accuracy/minimize deflection, the OB Break shaft is not going to "excel" at jumping balls - comes with the territory. But that doesn't mean that an educated jump stroke & mechanics might not provide adequate performance from a jump/break cue perspective. We all know that JB's do an adequate job of jumping, of themselves, but maximum effectiveness requires a dedicated jump cue.
The Samsara JB tip is really VERY impressive. Hardest leather I've ever seen - harder than the hardest water buffalo imo. Takes chalk well. You can use english effectively, keeping in mind it is a very hard tip. As soon as I can get to my cue tech, I'm going to replace all the white diamond tips I have on shafts w/ the Samsara jb tip. I think they are far superior.
OB has a jump shaft in the works, and Royce seems pretty happy with the results they are achieving. I happen to believe that OB is soon going to provide separate break & jump shafts that each do superior jobs of their appointed tasks. Will I be willing to give up my JB cue for 2 separates? I don't know. I have numerous dedicated jump cues now, and I tend to stick w/ the X Breaker even when I have a jumper with me.
Some guys wanna jump their way out of everything. I'm a believer that you can usually employ better control with a judicious use of kicking - but I'm not afraid to jump when necessary - if the rules allow.
Good luck to everyone!