That Javelina is a coooool handgun, J. R. WEEMS!

Barrel or no, I would not use that pistol to shoot .45 ACP. The breech face is not expecting a larger .45 piece of brass, I don't believe that it would work and it most definitely wouldn't do your extractor any favors whatsoever, and finding a replacement extractor should be possible but it isn't going to be nearly as easy as finding a standard .45 extractor.

If you want to fling .45 Auto from a pistol that looks exactly like that, you need the AMT Hardballer Long Slide.