I switched out the gas block on my S&W M&P 15 OR last weekend. I switched to the Yankee Hill Hooded flipup front sight gas block with rail (YHM-9835-H) and am very happy with it.
Front Flip Sight Tower w/ Bottom Rail, Hooded [YHM-9835-H] - $125.00 : YHM, Yankee Hill Machine Co., Inc. | Makers of High Quality Firearms, Accessories & Sound Suppressors, Makers of High Quality Firearms, Accessories & Sound Suppressors
There are two key things to removing the 15OR gas block (both mentioned in the thread you linked):
1) the gas block pin is driven out from the right (extractor side) to the left. I hear this is abnormal. With a hardened nail punch, and a good size mallet, the first hit knocked it right out of there (guess it helps when you drive it in the correct direction
).
2) Way down in the smaller hole in the bottom (the one a normal sling mount goes in), there is a set screw. I think many don't noticed that. Lossen the set screw, oil the barrel, heat the old block; and it slides off without much push.
The hardest part for me was getting the gas tube roll pin out (and that should be easy, btw - might be good to have spare gas tube on hand, I did). Good new is the barrel was finished under the gas block, and everything lined up perfect and looks great! Got to put 200 rounds through it on Sunday, and have to say I am very happy.
It really wasn't hard. I stressed more getting ready to do it, than actually doing it
.
If you hate your high profile M&P Optics Ready gas block.....
. I like the YHM hooded site as it block less of the front view (not that that was an issue with the Magpul front or anything). 
Linear Mode
