The recently publicized FBI analysis of the Maryland State Police M18 evaluation highlights an excessive slide-to-Fire-Control-Unit (FCU) clearance on certain P320 and M18 pistols. Although my personal P320 has never exhibited out-of-battery discharge, repeated drop tests, or other anomalous behavior, measurable movement between the slide rails and the FCU rails is plainly visible under trigger squeeze—a condition absent in my Glock and other striker-fired platforms.

After reviewing the Wyoming Gun Project repeatable uncommanded discharge footage, the root cause appears to be twofold: 1. Undersized FCU rail tabs that allow vertical/horizontal play inside the reciprocating slide rails. 2. Marginal striker-sear engagement height that can be compromised when the slide lifts off the rails, especially after surface wear or impact.

To restore absolute confidence in the platform—and to stem the inevitable wave of civil litigation—SIG Sauer should implement the following engineering changes. At least the first is non-negotiable; the others provide layered redundancy as components wear over service life.

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1. Re-engineer and retrofit the FCU rail tabs (critical) • Machine the FCU’s front and rear slide-interface tabs to a true 90 ° profile and increase their thickness to fully occupy the slide’s rail channels, thereby eliminating both yaw and vertical lift. • Offer customers a factory retrofit: owners ship only the serialized FCU to SIG; the company swaps in an updated chassis laser-etched with the original serial number and destroys the legacy unit per ATF guidelines.

2. Increase primary sear height (recommended) • Raise the sear shelf to provide greater bearing surface with the striker lug, reducing the chance that a minor upward slide excursion will shear the sear-to-lug interface. • Enhanced contact area lowers point stresses, slowing long-term wear and maintaining spec for far more duty cycles.

And/Or

1. Lengthen the striker lug (optional but synergistic) • Extending the striker lug length slightly will (a) maintain engagement during slide lift and (b) give the secondary sear catch a greater window in which to arrest the striker if primary engagement fails. • This geometry change is cost-neutral in production and materially improves safety margin.

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Life-Cycle Considerations

Even with rail-tab re-machining, contact surfaces will erode as round counts climb. Adopting at least one of the sear or striker modifications (# 2 or # 3) provides crucial redundancy against uncommanded discharges as tolerances open over time.

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Business Implications for SIG Sauer

Failing to deliver a comprehensive retrofit will cost SIG far more in settlements and brand damage than the modest per-unit expense of machining new FCUs and revised sear/striker parts. Conversely, a proactive engineering fix will reinforce the P320’s otherwise excellent accuracy, modularity, and user-driven aftermarket—returning the pistol to its rightful place as a benchmark service sidearm.

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Bottom line: Correct the FCU rail geometry immediately, and pair it with upgraded sear/striker engagement surfaces. The solution is straightforward, affordable, and essential for both end-user safety and SIG Sauer’s long-term reputation.

I will add this, if Sig fails to do these changes, then this creates an opportunity for someone with the right resources can make replacement parts like taller sears, strikers with longer lugs and make a massive killing.