The second picture is definitely identical to the crest on the Columbian model 1950 short rifle in Ball. I think you are right. I suspect that means MRBOB has something rare and interesting.

David in Ark,

That is quite interesting. So apparently this carbine was also sold to Columbia and Ball was unaware of it. I assumed it was a shortened Model 1950 because Ball does not indicate anything about these appearing with the Columbian crest.

It looks like you have a Columbian FN Model 1950 short rifle (in .30-06) or a Model 30 short rifle (in 7x57mm). I don't personally know much about them, but comparing your photos to those in Ball's Mauser Military Rifles of the World 3rd ed. it appears yours has been cut down at some point. The leng...

The receiver and bolt were originaly in the white on WWI Gewehr 98s, so hopefully there isn't any blue on the action because if there is it was put on there later.

As stgeorgeNY said, condition is everything.