The old version was massively sensitive to ammo for accuracy (reliability was 100%). I've probably tested a couple hundred lots across various brands in my old one, and found maybe 2 that shot really well, the others on average are 3-4" at 100. It's far and away the most ammo picky gun I've ever owned, it's not even close. One lot of Tac 22, and one Lot of SK LR I've found shot really well out of it to 100, somewhere in the 1-1.5 MOA range, but everything else dozens of tests over the last few years, 3-4" is common at 100 or worse, it just throws huge flyers, even at 50yds. JP built this barreled upper as well.
This is a good example target from yesterday at the range. 100yds, 5-10 mph winds L-R, the groups on the left target are CCI STD, SK Pistol, SK Rifle, Wolf, and Eley Match. I often use the JP to shoot up partial boxes, or straggler lot boxes. The three 5rd groups on the right, are one of the "unicorn" lots that it likes, a lot of SK LR, the largest of which is 1.25". I find if frustrating when a gun performs this poorly, so if I take the JP 22 I know to bring a couple boxes of the "unicorn" ammo to at least get some good groups in at the end of the day. I must have been asking for punishment yesterday cause I also took my MCX out, which I doubt could hit a dinner plate at 200yds with any ammo, yet SIG says meets their 3rd 4MOA std......that they evidently test at 25yds.
I've tested probably at least. a dozen lots of SK LR, and the others end up looking like the target on the left. No idea what drives it, my only wild guess is that the gun is ridiculously picky on pressure/velocity to feed without damaging the bullets or bolt bouncing perhaps. If it was bolt bounce though you'd think softer loads would do better. I can't think of any other reason to see that much accuracy variation from lot to lot of the same ammo and it being this hard to find a lot/brand it likes. I see lot to lot variations in my CZ 457 or Volquartsen/10/22s, but it's much much smaller, once and awhile you get a horrible lot, but most lots of the better ammo shoot pretty similar. Also the lot based flyers are usually velocity related so you still get pretty good L/R groups just vertical flyers, but the JP tosses flyers everywhere. It's also not that this "unicorn" lot is just amazing in general cause it's just middle of the pack in my 457 for SK LR lots I've tested. In the past I've thought about trying different recoil spring rates to see if it impacted things, but honestly I just find the gun frustrating to shoot.
The new JP might be amazing, but they'd really have to prove it to me first that it's not crazy ammo picky, and it lives up to the marketing, esp. since it appears to use the same action/bolt setup. That said I do think their fully built rifles seem to delivery better accuracy on average than just buying their barrels and doing an assembly. I've had several supermatch JP barrels built up and while they were all good, none of them were outstanding when compared to offerings like Bartlien/Krieger etc. but they are not far off in price.