I feel your pain
I have run into the issue, which I detail else where in the forum
. I think three things are happening leading to the trouble. Each issue on its on wouldn't be enough to cause the trouble with the stovepipe jams, but all three at once, well you're going to have a long day.
My working theory...
1) the ammo. I love the Winchester 333 (22LR333HP), 'cause its cheap, but its also crap. It is, at times, underpowered and doesn't eject with enough force to clear the rifle, before the bolt slams shut, trapping the empty.
2) Its dirty. The Winchester 333 (22LR333HP) is a dirty bullet, and that dirt build up has an effect a number of things in the rifle. In this case, the build up of dirt is hindering the extraction hook, enough to cause trouble in the ejection process. Also I believe there is enough build-up in the chamber to slow the ejection of the spend casing. its working as friction layer between the brass and the chamber wall.
3) Its new. I believe that you'll have more trouble in the begin of the life cycle of the rifle than you will later. The new barrel is still tight and or rough enough to slow the ejection of the spent shell. The spring on the bolt is young and fresh making the bolt at its peak. While I see the magic break-in period for a new rifle to be about 200 rounds, I think it more like 2,000 rounds!
So when these three factors come together you get stovepipes. So how do you fix it?
1) Try a different (more) ammo. There's lots of stuff out there, you'll find one that works well for you.
2) Keep it clean. When my rifle starts with the stove pipes - I take a minute and pull my Bore Snake through it a couple time. At the end of my shooting day, I now clean up the rifle, focusing extra attention on the chamber, and extractor notch. I use to be pretty lazy about this, but no longer.
3) Shoot it more. That's the best part! I think the rifle needs a little more break-in time, and the best way to do that is go out and shoot it.
I've also order an "Exact Edge" extractor
online, its under $20, you can't not get it for that price.