I bought this quite some time ago.  Wasn't really paying much attention when I bought it.  Was advertised as a Colt barrel which I doubted but didn't really care, although I did need a Colt style for my build.  After I rounded up all the other parts I noticed that this chamber doesn't look quite right.  Just wanted to confirm, is this a Olympic Arms style or something else?

It's definitely not an early oly bbl. They used a tapered chamber and bolt. Unsure what they sell currently.

Not an Olympic.  Might be one of the direct impingement pistol caliber types.

Thanks for the responses, this one may be more of an odd-ball that I had originally thought.  The worst part is that it won't do me any good and on top of that, I can't sell it not knowing what it is.  Lesson learned for sure!

U might be able to take it to a machinist and have the locking lugs machined off flush with the chamber face.  Finding some colt 9mm barrel measurement specs may help.

A friend offers the following advice:

"The barrel you have is definitely screwy and I would guess a one off by a clever home builder.  Best guess is it was made to use a modified M2 Training bolt....a bolt made to use plastic cased 5.56 training ammo for force on force training by the military.  All you have to do is open up the bolt face and add a weight.  I made one similar several years back in .45 for a fellow on weaponsguild.  They can be found on gunbroker occasionally and use a standard AR firing pin, extractor, and ejector....so it would be usable with Sten mags as the hook ejector of the colt pattern system is not required."

Thanks for the feedback everyone.  I ended up wanting a shorter barrel for 9mm anyway so it's probably not worth the effort for me to modify it, and it sounds like it's unusable for anyone else either.  Well, lesson learned...pay attention!