strange luger

I think I sort of know what this is but maybe someone can

give me a little more info. I bought a luger six months ago at the Tulsa gun show for $325. It has 100% blue but is a reblue because there is some light pitting under the blue in several places on the pistol. The SN is 1616q and all the parts are marked 16. The grips are walnut and look brand new. On the left side of the chamber is a very light small crown over the SN. On the top of the chamber is (1916). On the right of the chamber is (crown over B with small BG over that)to the left is (crown over W) to the left is (crown over R). On the toggle is (42) and on the left side of the toggle is a small waffenaut. The bore is perfect however when I went home and tried to chamber a round it stuck halfway in the chamber. After looking closely with a magnifing glass I noticed 2 burrs on the face of the chamber, one at 3 and one at 9 o'clock. I used a small file on them and the pistol function perfectly now. It is import marked (9mm Germany SAV GA). Any info about this gun and why the burrs were there would be welcome.

Regards,

Sherrick