^Not true. HK upper or lower will fit on mil spec upper or lower.
Smith and wesson did ...
Why not to buy anything from HK, by Larry Correia
Warning: do not click on that link if you are eating/drinking, unless you want to clean your screen and keyboard.
Do you know this for sure?
I'm an HK fan, but do not see a 300%+ premium over my my Colt 6920.
^^^ This. Does the HK offer 3x more benefit/performance over a tier 1 AR? IMO, hell freaking no.
If you want a piston gun, then get one that was designed ground up to be a piston rifle like the SCAR or even ACR.
When you hold an MR556A1 it feels like there is nothing you can do to accidentally break it. It feels like a substantial weapon.
That is H&K love making you feel that way. In no way is the H&K any stronger than any other AR. It is substantial because it has an overweight free float handguard and overweight gas piston system. You can get a lighter rifle from Daniel Defense that can take as much abuse as an H&K.When you hold an MR556A1 it feels like there is nothing you can do to accidentally break it. It feels like a substantial weapon.
Just my opinion, and I am biased. The MR556 is a nice gun. It does nothing that a $1k Colt, Daniel Defense, BCM, M&P15, or other high quality base model AR won't do. Here's my recommendation:
-Buy a $1k high quality AR, a dozen extra mags, a good sling, and a sight adjustment tool
-Buy a few cases of ammo
-Go browse the Training Section of this forum
-Sign up for a training course or 2 from Grey Group with the remaining money
I PROMISE you, the experience you'll get taking a training course or two from some of the former tier 1 BTDT types will be worth far more in the long run than the looks you might get having the "cool" gun on the range. I can't reinforce this point enough.