I had two 40XBs & one 40X from the CMP originally. A good friend talked me out of one of the XBs, and it went to a good home, as he's bought some period correct iron sights for it, and intends to keep it in original condition. Of the two I had left, the 40X was by far the roughest of the two, so I sent it off to Jonathan for the repeater conversion, and put a Benchmark 3-groove bbl on it when I got it back. It's a slick action, feeding & extracting/ejecting pretty much flawlessly. I put it in a skim bedded B&C #2015 stock with PTG Stealth DBM, added a Jewell HVR trigger, EGW 20 MOA scope rail, Athlon Cronus 4.5-29x56 mil scope, and threaded the muzzle of the Benchmark for a SWR Spectre II suppressor. Aside from the fact that I'd ordered the BM bbl in Rem sendero contour to finish at 26", it's all I'd hoped it'd be - very accurate, tons of fun to shoot, and a great way to get a lot of trigger time without worrying about shooting the bbl out. Just wish I'd had the sense to go with a finish length of no more than 22" on the bbl blank, as it's way heavier & a little awkward to maneuver around a barricade with the 26" bbl, especially with the extra 6" of length with the can mounted.
Against my better judgement, after having enjoyed the 40X repeater enormously, I sent the remaining 40XB off to Jonathan, and went pretty much the same route with it, only putting it into a spare Manners T4A mini chassis stock, and putting a 22" Krieger on it, which makes the longer bbl'd 40X seem even heavier & more clumsy in comparison. If I hadn't converted these two rifles, they'd be gathering dust in the closet, as I've got a nice 2011 Anschutz for prone smallbore & practice. As it is, since I've gotten these two 40Xs finished, they've been being shot far more often than the 2011, and I really don't have any regrets.
The photo shows the 40X, 40XB, and a V-22 I built after the actions became available.