Not much, but I’ll share what I believe to be true. I have shot one but not extensively and have no long-term experience. Bill Laughridge of Cylinder and Slide sells the parts to convert a conventional single-action Hi Power to the “Safety Fast System”. For information check the following link:
http://www.cylinder-slide.com/sfs.shtml
It can be installed and used or removed and with the original parts back in place, the gun functions as it did before, i.e., single-action.
Hi Powers can also be purchased through the maker Fabrique Nationale (FN) in the SFS form. (FN manufactures the Browning Hi Power. Browning Arms simply imports the gun, but Browning doesn’t offer the pistol in the SFS configuration.
In a nutshell, here’s how it works. A round is chambered and the pistol is cocked. The hammer is pushed forward with a thumb and the ambidextrous thumb safety engages. When the safety is disengaged, the hammer automatically springs into the cocked position for a single-action press of the trigger. There is no longer and heavier double-action shot to contend with. Trigger pull is consistent from first shot to last.
As this is written (January 21st, 2005) new SFS FN Hi Powers can be had from CDNN Investments (www.cdnninvestments.com) at reasonable prices. The most obvious way to recognize a Hi Power having this system from the conventional is that the SFS Hi Power will have a very abbreviated hammer spur. The slide stop lever and thumb safeties will appear a bit differently shaped as well.
Downsides to the system is that the slide cannot be locked back for disassembly as it is with the standard Hi Power and it does add a greater number of parts to the pistol. More parts can mean greater potential for malfunction or breakage. Users are not reporting problems.
Do I intend to get one? Probably not but having said that I do not rather boorishly reply, “It’s a solution to a non-existent problem” as have some others. I have no safety issues about Condition One Carry. Others do but would like to carry a Hi Power. The SFS system allows them to do that without the hammer actually being cocked. If the safety inadvertently wipes “off” on a single-action Hi Power, a press of the trigger is all that’s required to fire the pistol. If this occurs with the SFS, the hammer is instantly cocked and it possible that this would alert the carrier to the mishap. Either pistol in a holster covering the trigger guard is still safe. If nothing can touch the trigger, a properly working Hi Power will not fire.
Other people are prohibited from carrying single-action automatics by policy. The SFS allows them to carry the Hi Power (or 1911) as it is no longer strictly a single-action for the first shot. The hammer forward looks “safer” to administrators, city managers, and others not really competent to judge what is and is not safe.
For myself, the jury is still out on the SFS. I’ve not used one much at all and I’d like to see how they function over time. Relatively few folks will use these guns compared to all those using Glock, SIG-Sauer, or HK handguns, so getting much long-term information/observations will probably take longer than with more popular handguns. I do think it may prove a viable and dependable system.
Best.