Not sure if the MR223 is different, but one of the great things about AR's in general is the ability to swap out uppers and essentially get an entirely different rifle. .22 upper is great as a trainer. Cheap ammo and no recoil. I have a 7.62 x 39 upper as well. Nice blaster. I use mostly cheap steel cased ammo, so it's not as accurate as 5.56, but still a ton of fun to shoot. If you are looking to shoot longer distances, the 6.5 grendel in a great round. Not sure what the laws are in NL, but if you can have a suppressor, 300 Blackout is definitely something you should consider as the subsonic rounds work great with a suppressor.
Ultimately, what direction you go with additional uppers all depends on what type of shooting you want to do.
Ultimately, what direction you go with additional uppers all depends on what type of shooting you want to do.
