Yep, no problem. Drop a G33 barrel into a G27 slide and you are off and running! We also recommend you use the correct magazine with every conversion. This is cheap insurance helping you avoid accidentally shooting the wrong ammunition out of the wrong barrel.
Turn your G27 or G33 into a 9mm with this conversion barrel http://bit.ly/o2a1rB
BTW: Want an extended barrel for your G27? You can drop a G23 or G32 barrel right in.