lshel

I went with the M&P 45 full size. The small backstrap gives the grip a very good fit to my small hand.
It was also used from a TGO member at a decent price.

Thanks for everyone's input. I bought the 66-2 to shoot and that's what I going to do. I've had several Model 66's in the past, since I started shooting handguns in the 60's. I've always liked the balance/feel of the K frame over the L-frame. If it doesn't live up to my shooting expectations then I'll sale or trade it.
 
I usually shoot hand-loaded 357 mag with Unique or Accurate #2 to get velocities 1100 to 1200 fps for a 125g Hornady XTP bullet. Recoil is not as bad as the regular 125g HP 357 factory loads and I assume the forcing cone will be subject to less pressure. Accuracy in my GP100 4" with these loads is very good.

I bought the Hogue finger groove grip for the K/L frame. Bought one used for $15. I wish they made this grip without finger grooves.

This morning after being in freezer overnight, I took gas block and gas tube to work bench and hit back of gas block with several hard taps with plastic pallet to maybe loosen tube. I tried to pull tube out by hand, but no progress. I put gas tube in leather padded vise and clamped very lightly and had gas block sticking out one end of vise. I then took plastic pallet and lightly tapped gas block pulling gas tube from gass block opening. After seperating the gas tube from gas block, all looks good.
 
My wife has some plans for this Saturday morning and probably most of the day. Later this afternoon or Sunday, I'll finish installing new low profile gas block and new MI 12"' SS Gen2 free float handguard to M&P10.

I followed the above advice and bought a tap and die set 1/4"-20NC with #7 drill bit. Drilled and taped thru primer hole and used washers and 3/4" 1/4"-20 allen head bolt.
After tightening bolt down pretty good casing slipped out.  Somewhere along process I broke decapping pin. Have to go pick one up tomorrow. The 7.62x51 Nato LC brass is really going to get a good lube prior to sizing. Thanks all.

Midwest said this hand guard would not work on M&P10. They suggested the SS single piece for DPMS 308.

I've received e-mails from Troy Imdustries, Samson Industries and Diamondhead Industries. All have flip-up sights that will work on the M&P10 and are strong/durable. I went with the Troy regular folding front/rear sights.  Their Tech said the micro folding sights would not work on the M&P10.

CMP recognized SASS ID so ordered 200rds of Greek 150g M2 ball for $98 + $12 shipping, about $0.55/rd. Thanks TGO. I may try reloading brass from this lot. I've never reloaded rifle rds except straight wall 45-70. I also checked and Brownell's has adjustable gas plug for $39, may try one later.