This thing is sweet. 10mm report with a 9mm kick if that. I rested the pistol buffer tube on my shoulder with no pain.
That 30 round mag brass catcher worked perfect too.
Thank god I have another 500 rounds on order from Ammo to go, cause 50 rounds just aint gonna cut it.
For whats its worth, there have been some concerns on the AR57 uppers killing brass, mine did not. Brass looked fine as once fired dirty brass could look.