I was reading some of the posts in the thread about serial numbers, and seen a lot of references to updates/problems(ex. blue springs) with certain serial numbers.
Can someone give me the jest of the problem/updates with certain serial numbers.

they seem to be sequential based on mfr date, and it's only the oldest ones that had issues. at this point it would have to be years old stock to have spring issues.

Considering the demand for the M&P15-22 (not AR15-22), I seriously doubt there is any new rifle older than a few months (at most) sitting on anyone's shelves.

I think any fears you have about design problems are unfounded.

Just got mine back yesterday, only info I got was that it was brought up to date! Heard that you may get extra clip when you have to send it back, didn't get any info on what was wrong let alone any extras. Bought in mid march, returned mid march, turn around was fairly quick after they received it. DZL was serial#

I suggest just taking your rifle out and shooting it. If you have problems, then start worrying about the springs and whatever. No sense in worrying about something that you don't even know is an issue (and it probably isn't an issue).

Not worrying, was just curious about all the comments on it. Thanks..

Remember the "cat", who was also "curious"