During my normal Sunday morning range visit, another club member with a new 15-22 had a OOB discharge and extractor blow out after about 10 or 15 rounds. The entire rear of the cartridge case blew out. I believe it was a Federal round.
After examining the case and gun and insuring there was no slug stuck in the barrel I reassembled the extractor for him and the gun worked properly for the remainder of his session.
The spring tensioned retaining bar was the newer type with the lug on it. This lug made it reasonably easy to reassemble the extractor into the bolt.
This was the first time I have seen this happen to a 15-22 at our range. We have about 6-8 members or friends of members who have 15-22's and bring them reguarly to the range.
LTC