Hi Ray! I think you’re right and I also believe that a gun built to the Colt specs is still the gold standard in AR-15’s. It’s great to see how they’ve made a great gun even better. Of course there are others who’ve done so as well. LWRC and HK to name a couple. Ironically, Colt has its external short stroke piston design just like the 516 but it was never adopted and has not seen commercial success. Colt seems to get in their own way when it comes to selling their great products to the public. Thanks for watching and commenting.