Originally Posted by Con Murder
Fitting issue with A&K M4-S where we had to dremmel the upper receiver (metal) to get it inside. This gun is still on the bench and so we will test after the fitting is complete.
Some fine shaving of the receiver and the 'wings' on the hop-up go in smooth and stays steady. I did not like working on that A&K, we named it Cartman cuz it is an asshole. I do not recomend A&K M4-S if you plan to upgrade.