Lothar Walther. (Considered leaving it at that and probably should have but....).
As long as the air delivery system gives a consistent puff of air to the back of the pellet, the guns should be accurate.
Yes, barrel prep work (lead, crown, polishing of the rifling) can optimize accuracy and yes, a bad barrel comes from LW occasionally, but many (most?) other high end airgun companies are using the same brand of barrel. With the exception of FX, but that's a whole different can of worms, cost-cutting, profit-enhancing worms.
If you're willing to follow who is getting guns and when they're getting them you can see the first person accounts of accuracy. A guy down south received one maybe six weeks ago in .177. Purchased for his daughter for field target. He posted some accuracy results on GTA with a variety of pellets, either today or yesterday. He's kinda got a running review going. A guy in New York I think got one about three weeks ago and made some short little videos standing in front of a pool table with the Raptor sitting on it. In one of those videos he also shows a tiny little group shot with his Raptor. Travis has also posted more than a handful of videos, usually on Facebook, of accuracy results from the Raptor variants, in multiple calibers, power output and even pellets and slugs from the same barrel.
The info is out there, you just gotta dig a little since the marketing bucks aren't there and JSAR doesn't have the biggest YouTube personalities on payroll.
I've got one on order. I may sound like a fanboy but I intend to post results, positive or negative. If I expected negative I wouldn't have ordered it though.
So, LW barrels and each gun gets tested extensively before it ships out. I'd hazard a guess that they're getting tested more thoroughly than most more recognized airgun manufacturers test before they ship the guns out to their dealers. The fact that JSAR really needs to prove themselves right now makes me even more confident that they're making sure each one that leaves the shop is exceptional. At this point in their venture, they can't afford to let a dud out the door.