x-bullets in contender?

[Biathlonman]

I just got a new carbine barrel in 6.5x.225  improved (ala 6.5 JDJ) and was looking over JD's data that said avoid X bullets.  Is there a reason for this that I'm missing?  Seems like if you started low and worked up it shouldn't make any difference, but maybe I am missing something.

I would really like to try out the partial box of 120 X bullets I have on hand and thought I would do the usual start low and work up with Reloader 15.

Thanks for the imput!

[GBO MGMT]

The something you are missing is that there is no load data available for them and even Barnes tells you don't use data for other bullets when loading the X bullet. Another thing you are missing is that at the pressures at which the Contender is safe with this round THERE ARE NO VISIBLE PRESSURE INDICATORS you can rely on to tell you that you're there to stop before you are way beyond safe and have strected your frame.

Many will argue with that last point. So be it. ALL pressure testing I've seen reported has concluded that there are absolutely NO reliable visible indicators at anywhere near safe pressure levels in the Contender for a round of this case head size.

GB