I bought one of the often-belittled Norinco copies a few years back in near new condition because it was offered to me for $35. The extractor had a broken finger and the fellow said he couldn't find a replacement. I figured that it probably wouldn't take much to fit a Browning part and even if it didn't work I wouldn't be losing much.
Got the replacement from Brownell's and it dropped right in, no fitting required. Also found out the probable cause of the failure: loads of crud under it kept the extractor from moving as it should and literally hammered it to death. IMO, the same neglect would've had the same result in a 'real' Browning, too.
It's really a sweet little carbine. Light, handy, extremely reliable with all sorts of HS .22 LR ammo and capable of a much higher order of accuracy than I would've believed with its favorite flavors. If I ever run across a nice used Miroku/Browning at the right price I'll be sorely tempted.
A couple of personal comments: A carbine with the potential for precision shot placement these have really deserves better sights. Personally, I passed on glass and had a Lyman 66 installed. The non-folding rear leaf was replaced with a Marble's folder, too, but I've been known to wear a belt and suspenders so YMMV.
The front got a Williams FO bead. Works better with my bifocaled eyes and either rear.
Love the take-down feature! Quick, easy and makes for a very compact package. With good sights and an inexpensive cordura case it's a great alternative to an AR-7. Also gotta love ol' JMB for including an easy way to tighten up the barrel/receiver fit to compensate for looseness or wear.
If I ever do come across that Miroku and it shoots as well as the Norinco does, I'll do the same sight changes, install a LH trigger and reverse the safety, send it off to Robar for NP-3 and have my idea of the perfect all-around recreational RF carbine.