I found a small batch of .45GAP brass at the range I work at. I took them home and loaded them with a 185 JHP and using SPP and Clays powder. Some of the cases would not fit tightly in the Full Moon Clips. However once the cartridges are in the chambers, the FMC will hold them in place and eject them when done shooting. In my case, accuracy was no different than using .45 ACP cases.
Just thought I'd share this in case any of you find a batch of .45GAP and have a 1917 or 625 that you load for.