After posting my initial observations there were some more questions thrown out, all that I didn’t even think about covering in the first post, so I did a little research to get smart on the other .308 ARs by watching a cleaning video on youtube for the Armalite AR-10 and a few videos on the DPMS LR-308 so I could compare and contrast it the M&P10. While seeing these, I noticed a few more similarities and differences between the .308 ARs already on the market and M&P10.
The buffer looks a lot smaller than the Armalite AR-10’s buffer. I noticed the M&P10’s buffer was proportionately smaller than an AR15’s buffer to buffer spring, so I broke out an AR15 buffer to see how the M&P10’s buffer compares to it, and it is absolutely smaller than the Armalite AR-10 buffer. It looks like the same size as an AR15 buffer, but it may have weighed a little more (even though I did not do a precision weigh). This is in addition to being kind of beat up where I could tell it had hit the buffer retainer pin more than a few times. The picture I posted in my earlier review did a poor job of showing the wear on the buffer. Hopefully one of these two do a better job of showing the out of the box wear on the buffer.
The BCG looks like a hybrid of the DPMS and Armalite BCGs. The shape of the M&P10 bolt carrier is like a DPMS in that the bolt carrier is not rounded on the left side like an Armalite AR-10 bolt carrier. Another DPMS characteristic of the M&P10 BCG is that the S&W bolt assembly has three gas rings, as opposed to the Armalite single gas ring. The M&P10’s firing pin is almost identical in appearance to the Armalite AR-10 firing pin, with an additional spring to help prevent inertia of bolt closing sending the firing pin forward, or at least according to this video. The DPMS firing pin does not have this spring.
Pictures of the gas block and barrel without handguards were requested during feedback on M4Carbine.net. I also added better pictures of the what I condenser light staking on the castle nut.
Also, I want to add that not everything was horrible with the trigger. The reset was very pronounced and easy to feel when I dry fired. I hope the reset remains that easy to feel when live ammo is producing recoil.
Again, I am no AR expert or .308/7.62 expert. I hope these additional details can help you decide if you would purchase a Smith and Wesson M&P10. If you have any other requests about this rifle, if you post them here, or in the threads on AR15.com or M4Carbine.net I will gladly try to answer them.