It seems to me that Sig designed this weapon specifically to compete for this contract. Some other features that probably helped in selection include being ambidextrous, and it can be disassembled without tools, and round in chamber indicator...all throwbacks to the selection process that got the M9 its contract.
I think the high center of gravity is going to be a given. When I was in the army, we were often warned about not letting the slide cut the web of skin between thumb and finger...meaning that apparently this had happened to somebody along the way - a lot of soldiers come ‘off the street’ with zero experience with handguns, and really the range training isn’t frequent enough to gain a lot of familiarity. There’s also the issue of trying to hold the pistol with gloves on. So they will always keep a tall grip.
I just wonder what its nomenclature will be - M320?
I’d also though about the military shooter probably more often than not wearing GI gloves, as gate security forces and guard duty personnel will be expected to. Yet another layer of stacking tolerances which will throw off accuracy with a full grip and lower hand web purchase. The .45 ACP Glock 21 is usually too big for most shooter’s grip, and a holding a Glock 19 wearing gloves makes it feel like a Glock 21.
One curious addition is the pronounced beavertail on a striker fired pistol. I understand the geometry of the Sig 320 was developed from a hammer-fired Sig model and I wonder if they really considered its necessity.
The only thing I really know about the new Sig 320 service pistol is that it apparently met all the US Army requirements in the specification bid sheet. Now its left to be seen if those requirements weren’t dubious to begin with. I’d probably struggle to make a list of requirements which satisfies husky US Army Delta Force warriors as well as tiny female USAF military police who have little doll hands.