Any experience here with the mag replacement spring and follower for the 8 round/7round shield mags to increase capacity by one.....are these reliable? what about the possibility for misfeeds??

Any info would be appreciated.....

To be honest, I've never been one for adding one more round. Not because if may or may not cause a malfunction. I just put the money I would have spent on the +1 conversion toward a extra mag. It's a training mindset for me as, if I needed a extra round for whatever reason then what the heck did I do with first 5-6 shots.

I carry revolvers exclusively now and I always get razzed by friends over capacity conversations. If I need it I should have been finding cover by shot 2 and moving, reload at cover. If I need 7 rounds I'm already in deep and in my mind better to have a fresh cylinder then 1 extra round.

I know this doesn't address you question directly, but food for thought and a extra mag normally adds more value to pistol vs extensions. Another view point is spend money on ammo that will do the job.

I appreciate your thoughts...I have the 7 round mag in the weapon .and 2 8 round mags..that I carry ...I would give up the 7 round mag, and carry the 8 round in the gun with 10 on board (9+1) and carry just the other 9 round mag....seems more than enough firepower...

Just not sure if these increased capacity after market changes are reliable enough to trust your life on...if it were such a great idea, my did S&W not do it to start with??????

Just need to hear from folks who know more about these aftermarket products than I do......

Check out the S&W M&P "Shield" forum. I've seen where others posted about their successes with the Magguts addition.