Wilson’s Grip Module
While there’s a metric boatload of “custom” in this pistol as compared to the standard SIG SAUER P320, a significant departure from the stock handgun is the frame itself. The P320’s modular (and serialized) internal fire control unit contains the entire action including trigger, sear, springs, safety components and operating controls — everything except the magazine release button and striker assembly. This allows one to treat the frame, what most consider “the gun” itself, as an accessory. No federal regulations required if you want to swap it out.
The Wilson Combat frame offers a handling-friendly full-height grip with a carry-friendly 3.9" barrel. Benefits of this approach include improved handling without sacrificing full capacity. The two included X-Series magazines hold 17 rounds each.
One less visible frame improvement is internal compartments in the rear of the magazine well for weights. If you field strip the WCP320, you’ll notice three vertical channels (empty by default) where you can insert optional Tungsten bars. The set of three (two narrow bars and one larger) adds 42 grams to the back end, helping recoil control and providing some balance against the heavier fiery end of the pistol. If you go this route, consider using some grease or perhaps silicone for a more permanent, rattle-free installation.
If I were a serious competitor, concerned with shaving milliseconds from rapid-fire shot strings, I’d give the weights a try. For carry or recreational applications, I had no trouble with the WCP320’s tame recoil and muzzle flip impulses.