Which M&P15's had Picitinny rail fwd gas Block and untreaded barrels?

[serger]

I've got a friend who has a M&P15 that has a target crowned barrel, fixed folding stock (With the allen screw and no dimples on the recoil spring tube). It has the railed FWD gas block and the serial number is just over 98000. He bought it w/o sights and wants irons on it for cheap. I told him to get the UTG metal ones because it's going to be a 4-Wheeler gun.

It got me thinking, which M&P15's had unthreaded non-bull barrels? I figure this one's kinda early because the SN is below 100K but don't know anything about the S&W series because I've always built my own or bought Colts.

 

[Echo40]

I believe it's the M&P15OR "Optics Ready" model. However, an unthreaded barrel wasn't standard, IIRC, so it was probably made specifically for a state with regulations against threaded barrels.

 

[JRD]

Sounds like a ban state compliant version of M&P-15 OR (optics ready). Before the introduction of the Sport line, the OR's were the lowest priced SKU's.

S&W has made millions of M&P-15's over the years. There is a two letter prefix in front of those five digits in your serial number. Once they get to 99999 they go to the next block of numbers in a different two letter prefix, so you can't determine age based on the digits alone.

If the barrel is chrome lined and manganese phosphate coated instead of Armornite QPQ, then the rifle is probably an older one from before S&W debuted the Armornite finish in the Sport line.