I have a 21SF converted and love it. The conversion on a 21SF Glock will reliably and accurately fire .45ACP +p, .45 Super and .460 Rowland. The only issues I have heard using the shorter cases in the Rowland chambers have been with 1911s. Here is the converted gun. I hunt with it and it is devasting to deer. Using a 265gr Beartooth sized .451" it is super accurate.
Here are the OAL for loads with different bullets worked up to function well in the Glock:
Here it is with a group shot from sand bags