[AMDnutt]

I would run another 100 rounds or so through it before sending it back. You may have a tight chamber but it may be within spec, just on the lower end of the spec. If you have a failure to go into battery, eject the cartridge and look for marks from friction / rubbing. This may just be a tight gun. I've had a few guns that were on the lower end of the chamber spec (KAHR seems to always run tight) but I reload to fit...
I have seen a few (one this week) Springfields that were so tight the slide would not go into completely into battery. I looked at an EMP this last week in a gun shop and the slide / barrel fit was so tight it would not go into battery the last 1/8" - 1/16" without a nudge from your hand.
As for the breech, I would not worry about the machine marks. Please keep in mind that SA 1911 guns are always tight and require some break in. I would not carry any gun until I have had 500-1000 rounds through it, I have seen many that need to be "loosened up" before 100% reliable function (my Kimber took a little over 1000....).

 

[AMDnutt]

From your picture, it appears the load is "too light"....

What I mean by this is that the load does not generate enough force to "push" the slide back with enough force or velocity to allow the magazine to react. If the slide moves to slow or does not fully "retract", the mag spring will not push the follower upward fast enough which will cause the slide to start pushing the rear of the bullet too soon. The slide will catch the rear of the bullet and push forward before the mag follower is finished "seating" the bullet into the optimum angle or position. This will cause a jam that looks like what you are experiencing. Longer bullet "profiles", or shapes with long OAL ill increase this issue.

Several things can help this - switch to a slightly shorter and "hotter" load, or change to a different bullet shape (more rounded). Switch magazines to see if you have a weak spring (doubtful on a new pistol). And finally, polish the feed ramp a little.