Haha, SPA strikes again. I still like them for their value because they can so easily be improved, but I was optimistic that Diana would be instituting some quality measures to address this sort of thing. How disappointing.
Didn't the rep from Diana say on one of the ShotShow videos that the guns are shipped from SPA to them so they can inspect for QC?
Having worked with Chinese manufacturers before on numerous occasions, this might be less helpful than you think. This is for two reasons.
First, there is a question of time, how many man hours per gun are you willing to spend to QC each gun? Doing that adds to the price at a pretty remarkable rate, so the answer generally is not very long. Given that the barrels come with grease in them, and for their protection as they sit on stockroom shelves probably need to be shipped with grease in them, right there you've got 15 minutes of cleaning each barrel if you want to accuracy test each gun. Or take the regs, most regs take about 1000 rounds or so to settle in, is someone going to sit there and cycle the gun that many times?
Second there is the question of binning. Basically you'll have to bin rifles into three categories: sell, repair, and NFG. Generally Chinese manufacturers are not interested in hearing your ideas regarding defect rates, you own what you bought no matter what they screwed up. So only some percentage of rifles will be salable, some have to be flat out thrown out or scavenged for parts to repair some which may have simple enough issues that it is cost effective to repair and sell them. Doing this though can really increase the prices of the guns. If 1 in 10 is NFG, the binning alone is going to increase your costs 10% which is going to increase your sale price by 20% (distributor markups like this are often around 50%). So when it comes to price, you're going to have to decide what your bar for "acceptable" is, and it'll probably have a lot more to do with what the bean counters say than what the engineers say.
What is my point by saying all this? It can be remarkably expensive, often more expensive, to try and make a thing cheaply and then get it to be good. And in this case Diana is trapped between well respected brands who are just a couple hundred dollars more, and the other manufacturers selling SPA guns with a little less flash in the woodwork. It puts them between a rock and a hard place, and so I suspect they won't be sorting these rifles too stringently for quality.
As far as the crown goes, the inner part of the crown looks to me like it may have been cut with a tapered reamer. (although I could easily be wrong) That'd suggest to me that it is an entire process they did, thus it is a strong possibility the barrels are all like that. *shrug* I hope I'm wrong, because I know a lot of people have been looking forward to what is a really cool gun at a good price.
I hope something in this post was helpful or informative, if not particularly optimistic.
Diana just telling you what you want to hear
I will still buy the spa/ Artemis p15 have the 25 and 177 and thinking about getting it in 22. The ordinary Spa 15 stock works for me as I would spray paint it matte black. Don’t care for the fancy stocks Diana offers though nice, these guns are for plinking and hunting so a few scratches is going to bother me as this gun shipped from Krale is $525 shipped. The money I saved from not buying Diana netted me a new scope. If you folks are on the fence about buying a spa 15, better buy one now because spa said in order to get parts now for the p15 is through Diana 
