Looking at buying an M16A4 upper and had the seller send me a photo of the chamber area. Would this be the no-no combo of a rifle barrel extension on an upper receiver with M4 feed ramps?

Looks fine to me.

It’s fine.

That looks like it a little, but probably not going to be an issue. Like they started to machine M4 ramps into the upper, and then changed their minds after having taken the tiniest little nibble.

Yea, it kinda looks like the receiver cuts were home made. It might run fine though.

Thanks all. I'll think on it some more. Hopefully it won't be an issue when actually feeding/firing; those little two nubs on the upper receiver looked a little too small to be factory cut feed ramps so I figured I'd get a second opinion.

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Here's "the picture" for reference.  They don't look quite as deep on yours.

@Norinco22  this is the correct answer. There was an incorrect answer posted above.
With the combination extension/receiver in the photo you posted you may well have feeding issues.

May just be the way the camera/picture makes it look but too me it looks like the barrel extension may be too far into the upper coming out past the inside face of the upper.

Another issue is that the extension looks to be off center? I'm not sure if it's enough to cause the bolt lugs to bind against the extension lugs or not? It's off more than I would find acceptable.
As to the ramps. The M4 ramps in the upper are very small but they do appear to make a pocket for a bullet tip to catch. Bullets should ideally feed high enough that the bullets only contact the extensions rifle ramps, but that's not 100% guaranteed to always happen. 'If I owned the rifle', I'd start with centering the extension with the upper and then I'd extend the rifle ramps to match up with the ramps on the upper.
It may work totally fine as it is though?

Contacted the seller and he said that he "just noticed" the little two pits below the barrel extension; hand cycled a few rounds and said it worked fine.

Will still mull it over a bit, though.