In the case of the P-07/09, for irons aft, notice the distinct lack of real estate between the RDS and the dove tail. Same for the dove tail and the hammer channel. This situation is forced because the shop has to use the aft edge of the factory rear sight dovetail as the aft edge of the RDS footprint. There's not much room behind the factory dovetail for a custom dovetail. A quick and very dirty check with the calipers indicates that I might have .02" of material on either side of the rear sight. It's hard to tell from the crappy cell phone pic, but that's about half the width of the factory cocking serrations. That doesn't seem very robust to me.
Irons Forward doesn't impose that limitation on the P-07/09. In this example, I have about 0.10" (5x the material) between the hammer channel and the RDS and about 0.20" between the RDS and the custom BUIS dovetail. Much more robust, IMO.
Every gun is different, particularly hammer guns. Internal safety configuration, OE sight configuration, and a number of other things could change the preference to irons aft. For instance, it looks like the classic SIGs are stuck with irons aft because of the way the internal safeties are configured. H&K and Berettas are a hot mess.
As a high C class shooter, I'm under qualified to discuss shootability.
In general,
- For a carry gun, I prefer irons forward because it's one less sharp corner to poke holes in my shirt. (soooper cool guy tactical, I know)
- If there was any chance I'd go back to irons, I'd prefer irons aft.
- I have both. I'm generally ambivalent about the typical forward vs aft configuration arguments.
Cheers,
David S