I recently put a m4 barrel (with the m4 barrel nut) on an ar upper. I am noticing a little overhang at 2 points from the ar upper at the bottom of the m4 barrel nut. Will this affect performance of the rifle? I have talked to several people and while some have told me that it might not feed properly, others have suggested that I would have feeding problems only if I had it on full auto, which we all know I cannot and will not do.One person suggested five ling away some of the overhang so it is flush with the slant of the m4 barrel nut. I don't want to do this if I don't have to, so I want some input from those people on this forum who are more experienced than I am (as this is my first ar build). Thanks.

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The "barrel nut" is the thing that looks like a bicycle sprocket.  It holds the barrel on the front of the upper.  The "barrel extension," which is different for an M4-style barrel, is the part that goes IN the upper, and this part is what's related to feeding issues.

If you could post pictures of this overhanging material that bothers you, we might be able to help you out some.

You should be good to go. If you had an upper with the extended feed ramps, and a barrel extension without it, you could have bullet tips hang up on the edge of the barrel extension at the top of the receiver cuts. With an M4 extension and a upper without the cuts, you shouldn't have a problem. It might negate SOME of the advantages of the M4 feedramps, but it's not any different than having standard feedramps on the extension.

Check this out... there are 4 pics on about the 2nd or 3rd post.... you probably are looking at the lower right picture... you will be ok.


M4 Feedramps and A2 Uppers