Hello I'm a new user to AR rifles. I recently picked up a new FN15 MOE SLG edition. I overlooked a bit of detail that has now got me a little concerned.

On the bolt release side of both receivers, there is a raised "column" where the mag release is inserted into. The "column" on the upper receiver is wider than the one on the lower receiver. They look like a mismatched pair. Should I be concerned about this? I really would like to have it replaced if its at all possible by FN.. I'm concerned about this because it doesn't look like a properly made complete rifle to me.

Wanted to get some commentary on this matter.

Please see my picture with arrows below. Thank you in advance.

It's normal

It's nothing to worry about. Your rifle should work just fine.

Many different rifles from many manufacturers do not match up perfectly and have no problems.

If it still bothers you after a couple thousand rounds, throw it down the driveway a few times and you wont even notice anymore.

Most WON'T line up unless you buy a matched set (and even then it's usually only high dollar billet sets). Ironically the only forged set I have is an el cheapo Anderson lower with an upper of unknown origins

Totally normal. other side of the receiver doesn't match either fyi

Thank you all for the responses. I knew it wasn't going to affect how it functions & performs. It just bugs me because it doesn't look neatly put together (at least to me). Oh well I guess. Thanks again.

Normal and annoying.  I've been able to find mismatched uppers and lowers that align perfectly.  Both from different manufacturers.  It's gets worse.  Most of the time the anodizing shade/color/texture is off even from the same manufacturer.

Bottom line is.  Accept it.

I have seen it on complete DD and BCM rifles. No big deal

That is totally unacceptable, send the upper to me and I well dispose of it in a environmentally friendly way.