One word regarding UBR: heavy. I got that one on my KWA Kriss Vector and it adds a lot to the weight. Also I like my m4a1 unmodified, there’s something really sexy about the original look
Funny you should mention thredlock,.. Fortunately the nozzle I have has blue thread lock on it as standard... I've got it shooting at about 340 fps on Abbey gas at temperature 20c when tested this evening....
Anyway, my replacement Marui nozzle should be here in a couple of weeks along with other gubbins...
Unity Tactical Riser. Absolutely perfect height now for both eyes open and wearing a face mask. Back up sights are useless now, but let's be honest, they were always just for show.