The grooves can't be any shallower than Marlin's micro-groove rifling.
Will check one out, and report back on appearance of rifling.
I had two JW25A rifles. My wife bought me one and I had ordered another one later. They both shot well. I just sent the other one to a fellow CGNer. I am going to put a cheapo scope on mine and use it at our indoor range. They are a beefy little rifle.
It's okay boys, I have 6 CZ 455's, so no need to harp on the "buy quality once, cry once" blather. I treasure my JW25A as a gift from my wife. I also had a JW15 sporter, but it was stolen. It shot just fine, too.
Just to give you guys an update: 3 trips to the range and about 250 rounds through it. No problems with accuracy. It'll happily shoot 2 inch groups at 50 yards which is about all I'm capable of.