Sheesh, you guys must be really bored, this thread is over a week old.
Well, I never actually owned a 77/22...but I have had many problems with the 10/22 mags. I have had problems with both the factory mags and Butler Creek (although it was probably the ammos fault more than the Butler Creek mag).
Problems being failure to feed. After the first couple hundred rounds through the factory magazine I began to experience problems feeding. It seemed that every 3-4 rounds would just sit on the lips of the magazine. But with aftermarket mags, I didn't experience this strange phenomenon. So I trashed it.
Isolated incident? I think not. A friend of mine had the same problem after approximately 400 rounds in his factory magazine.
I really like the compactness of the factory design, but my experience is that the Butler Creek are more reliable. Of the three I have owned, only the first had some hiccups, but haven't had a problem since. The other two have been stone cold reliable.
It seems kinda strange that I would have better luck with the aftermarket mags because they don't fit as flush as the factory ones, go figure.
Was that explanation enough??? Sorry if I offended anyone with my opinion of Ruger's magazine
Stinger