I was inspecting my pistol and noticed that there are the numbers "2.2" stamped on the inside bottom of the back strap safety.  See the attached photo.  Does everyone else have these same numbers?  Does anyone know what it means?  Just curious.

Crimson Trace lasers for the R51 are currently $29.99 on CDNNsports

https://www.cdnnsports.com/crimson-trace-laserguard-remington-r-51.html#.XooRDohKhPY

Smoke color, Huntsville marked H025XXXR51.  Remington says June of 2018.

Yes, scouts owner, you are correct.  My statement says "Gen 2's were remanufactured... in Huntsville, AL".  So the leftover Charlotte parts were sent to Huntsville for Gen 2 re-manufacture and re-assembly. 

The next best thing to owning a Gen 1 is downloading the 3D model in "World of Guns".  The model is the Gen 1 so you can examine all the parts there.  There are a couple videos out on the tube that show the R51 3D model.

These are the changes between Gen 1 and Gen 2 that I have come up with so far:

• Gen 1's were manufactured at the Para USA plant in Pineville, NC marked "Charlotte, NC" until March 2015, eight months after the July 2014 recall.
• Gen 2's still marked "Charlotte" are remanufactured in the Huntsville, AL plant to receive the below listed revisions.  Starting in 2017 newly manufactured frames are marked "Huntsville, AL" and have the "H" prefix in the serial number.

• Gen 1's had the R51 logo rearward next to the slide serrations.  A larger pocket was milled in the slide for the hump on the breach block.  Complaints of rough racking.
• Gen 2's have a redesigned slide with the R51 logo forward near the ejection port to differentiate the New from the Old slides.  The new slide now has an FNC finish and smoother function.  Milling on the new slide is slightly different behind where the slide meets the breach block ramps.  Not sure what this is for as it is in a non-contact area.  A smaller pocket is milled in the slide for the hump on the breach block.  The action is considerably smoother.  The Huntsville plant used Hardinge Bridgeport GX300 VMC milling machines for slides.

• Gen 1's had a thin, flat magazine base plate known to deform.  Unmodified magazine weighs 1.7 oz.
• Gen 2's have a thicker, rounded base plate with the addition of a "ramp" on the follower.  It is still necessary to trim the legs of the follower yourself for proper operation.  Modified magazine weighs 1.8 oz.

• Gen 1's had a smaller, shorter disconnector.  The top of the ears are taller than the new disconnector.  This could account for some rough racking.
• Gen 2's have a longer disconnector to address trigger reset issues.  The pistol frames are milled to accommodate the new disconnector, therefore a new disconnector is not compatible with a Gen 1 frame.

• Gen 1's had an ejector that was stationary and had a larger profile.
• Gen 2's have an ejector that pivots/lifts and has a smaller profile.

• Gen 1's had a cadmium plated action spring (around the barrel) that was shorter, bushing was known to become scratched on exterior. The spring wasn't strong enough to put the slide back into battery, in some cases.
• Gen 2's have an action spring that is longer and PTFE coated in blue, bushing is replaced with a hardened chrome bushing.  The spring is stronger now and the demonstrated 1-finger racking is gone now.

• Gen 1's had a breech block that caused racking issues and cartridge deformation.  The magazine also interfered with the breech block when inserted.
• Gen 2's have a redesigned breech block with a notable haunch added for a larger surface to place the cartridge in battery (to help with nosedives and casing deformation).  The bottom deck was raised/lowered to not foul with the magazine.  There is a bevel on the leading edge and an eased out area near the extractor neoprene pad.  The extractor is redesigned to have a shorter claw for precise engagement.  The extractor is also slightly longer and the neoprene pad is moved rearward. The neoprene pad is now light green instead of black.  The barrel was redesigned to remove the "wings" on either side of the feed ramp.  The locking grooves on either side of the barrel, where the slide locking pin goes through, were reduced.

• Gen 1's had grip screws that were known to become loose.
• Gen 2's have a larger rubber O-ring that replaced the smaller O-rings at each screw as a lock ring.

• Gen 1's had front and rear sights that were known to drift loose from the dovetail groove, on some models.
• Gen 2's have stock front and rear iron sights that were redesigned to have a set screw to hold them in place, with the exception of using the fiber optic or tritium sights.

• Gen 1's had the sear pin, upper manual safety pin, and magazine catch pins that were known to drift loose, on some models.
• Gen 2's have the redesigned knurled pins that were replaced to stay driven home.

• Gen 1's slide catch pin is slightly shorter (0.9240 in/23.47 mm) and cannot be removed without the use of a helper tool.
• Gen 2's slide catch pin is slightly longer (0.9535 in/24.22 mm), when installed it sits proud of the frame and can be removed with the push of a finger.

• Gen 1's weigh 20.7 oz. without magazine.
• Gen 2's weigh 20.8 oz. without magazine.

Feel free to add and list other changes.

Were you able to use the stock torx screws or did you have to get longer ones?

Just picked a new one up for $299 using gun broker.  There is another one listed for the same price.

I was looking at the possibility of using a Hogue grip sleeve for the R51.  Not sure how it would effect the grip safety.

https://www.hogueinc.com/handgun-grips/handall-grip-sleeves/sleeve/handall-jr-small-size-grip-sleeve-black

Both retailers are currently sold out.

Just purchased a new R51 in the smoke color scheme.  Can't wait to take it to the range!