There has been some discussion about bolt carrier (BC) weights, and their effect on cycling and malfunctions. Some have solved their problems by adding weight to the BC.
Was able to compare weights of BCG from two rifles on a postage scale.

M&P10 purchased April 2013 BCG weight 18.0 ounces
(no date on the box)

M&P10 purchased Nov. 2013 BCG weight 18.2 ounces
(10/4/13 date on box)

Is that 0.2 of an ounce difference within the manufacturing tolerance range? Or has S&W increased the weight?

I bought mine in Oct. 2013, it has no date on the box. Next time I have mine out I'll weight it. I bet they updated it. Where and how would one add weight to their BCG?

My BCG is 18.1oz un-weighted... but 22.1oz weighted.
So we are talking 4 full oz

I am using a Tubbs CWS (Carrier Weight System) Tubb AR 15 CWS Bolt Carrier Weight System

I went this direction before before rojodiablo suggested an increase in buffer weight:
M&P 10 Short Stroking

both solutions will slow down the action and smooth out the recoil cycle.

I can't speak for the buffer weight increase, but the added weight in the BCG dramatically reduces the felt recoil. So much, that when in my RRA AR15, its recoil amounts to a slightly stouter .22 long rifle... and I am not exaggerating

Another change that would change the cycling properties would be an adjustable gas block. I may play with that this spring

Little confused Cowboy. Wouldn't adding BCG weight increase the short stroking symptom?

<Official Disclaimer>
I am not a smith

the issues a lot of folks had were initially called short stroking, and I am sure some were... mine was not.
When the mag was loaded with a single round, chambered, then fired, my bolt would lock back on the empty mag. those in the discussion at the time assumed the BCG was traveling so fast the mag springs couldn't keep up. These guns are way over gassed "all ARs are"
A real short stroke wouldn't lock back, because it doesn't travel far enough back.

There are so many variables acting at the same time here it is hard to grasp, and even harder to point a finger and say this is the problem. There is no question that if you can increase the buffer or bolt weight and have enough gas to cycle the action to support reliable feeding.... for a given powder burn rate and corresponding gas volume, it will slow down the cyclic rate, reduce recoil, weapon bounce, and spring twang and generally just smooth the entire cycle. The same amount of gas is there . It still has to unlock the bolt, and then all the variables kick in. The gas has to move the bolt into the buffer which now weighs more, but the mass that has to be overcome is increased so the bolt is moving at a slower rate. But this changes the gas pressure on the entire process because volume expansion rate is slowed. In other words the gas pressure is working longer. The buffer spring is returning more mass (slower). So Jack to answer your question maybe, maybe not. Is the spring compression too stiff? If so then maybe the increase in mass and a longer dwell reaction time will allow proper cycling aganist the spring. That is why the system needs to be matched. Thats why it takes a lot of knowledge or a lot of experimenting with buffers and springs or gas pressures and bleed off rates to get an exceptionally smooth running AR. Most components will run the rifle unless you get carbine and rifle parts ect mixed on the buffers and springs. I feel for a factory rifle, fed commercial ammo not to run is inexcusable. But it happens! Tolerence stacking, improper breakin, or lube can all cause problems. I would experiment with a CWS as mentioned above as one of the best ways to smooth an action out. Sorry this is wordy but it ain't as simple as it seems. Chief

First I'd like to say, "Always listen to your Chief"... Then if that doesn't work, take a look at JP's Captured Spring Buffer with the Spring Pack.

JP - Buffer Springs and Silent Captured Springs

__________________
Corpsman FMF/SW