AXG frame swap doesn't address the FCU problem—so why is it still the carry answer?

You've got the mechanics right, and I appreciate you separating the frame upgrade from the FCU revision—that distinction matters for how people reason about their carry gun.

Honest question though: do we have documented post-upgrade incidents? I ask because the litigation-era incidents you're citing (2016–2017 era, pre-redesign) traced to specific FCU geometry. Sig changed that geometry in production around 2017–2018. If someone bought an AXG today, they're almost certainly getting a gun with the revised FCU already installed, not pairing a new frame with an old fire control unit.

The risk case you're really describing—old FCU + new frame—that's a parts-bin scenario: someone who bought a 2016 P320, then swaps the slide and frame to an AXG but keeps the original internals. That's a real thing people *could* do, but I haven't seen field reports of it. The documented incidents all predate the FCU revision.

So I'm tracking with you on *framing*—say "this frame is nicer to shoot" rather than "this gun is safer." But I'm curious whether the actual risk scenario (old internals in new hardware) has shown up in the wild, or if we're mostly talking about how recommendations get communicated.

What am I missing? Have you seen post-2018 incidents tied to earlier FCU geometry?

Southpaw's got the empirical question right, and it's the one that actually matters for carry decisions. But there's a distinction worth making between "no documented incidents" and "the legal verdict on what was actually defective."

The litigation settled on specific findings: the pre-2017 FCU geometry created an out-of-battery firing risk under impact. Sig stipulated to that in the settlements and consent judgments. That's the controlling fact pattern—not whether someone *has* reported a malfunction since, but what the engineering investigation and legal record established *did* happen under the original design.

Now, your point about parts-bin risk: you're right that someone buying an AXG *new* gets a current FCU. But the scenario isn't hypothetical. P320 modular design means someone with a 2016 gun can swap frames and slides. They can also keep the original FCU. The fact that this isn't common doesn't make it impossible. And the legal record shows that specific FCU was documented as defective.

So the framing question becomes: are we relying on "no reported incidents since" as our safety baseline, or on the engineering fix that addressed the *documented* failure mode? Those aren't the same threshold. One is absence of evidence; the other is evidence of remedy.

The OP's point stands on that distinction. AXG is a fine platform. But if someone's buying it to remediate a documented defect, they should know the remediation was the FCU revision—which you probably already have if you bought new. Frame material didn't change the engineering. The engineering change did.

Not legal advice, obviously, but that's how the record reads.

Both of you are tracking the right questions, but I'll add what I see from the department side, because it matters for how we think about this.

We transitioned duty inventory from M&P to P320 starting 2018. Full fleet swap took three years. During that window, the armory didn't mix old and new FCUs—we documented serial ranges, pulled the old guns, staged them for inventory control. That's institutional discipline. A private citizen doing a frame swap? They're not running a log. They're pulling parts from a bin.

What I'd tell someone coming to the range with a 2016 P320 wanting to upgrade to AXG: you can swap the frame. You can make the gun handle better. But if your concern is the documented defect—and the OP's right that it *was* documented—then you need the FCU revision too. That means either buying a complete new gun with current production dating, or confirming the FCU serial is post-redesign. A lot of people won't bother with that second step.

Southpaw's point on empirical incidents post-2018 is fair—I haven't seen malfunctions tied to the old geometry come through after the revision. But that's different from saying the old geometry wasn't real. It was. Sig fixed it. The question is whether someone actually gets the fix when they're upgrading.

For duty use, we just replaced the whole platform. For carry, for civilians: know what you're upgrading for. Frame feels better. That's legitimate. But if you're trying to fix a defect, make sure you're actually fixing the defect, not just buying a nicer-looking gun with the same internals.

Frame swap alone doesn't guarantee that.

The department angle bluegrass.leo brought up is the real tell here. They didn't mix parts because they couldn't afford to track which gun had which internals. That's the practical problem baked into this whole thread.

Here's the honest risk framing: if you own a P320 from before 2018 and you're actually worried about the documented defect, you have three choices. One: sell it and buy new production. Two: send the whole gun to Sig and have them verify and update the FCU—that's a thing they do, takes a few weeks. Three: keep it as-is and accept that you're carrying a gun with a known historical defect, frame material notwithstanding.

Framing an AXG frame as the solution obscures all three options. It feels like you're *doing something*, but you're mostly just redistributing the same risk across better ergonomics. That's not remediation.

What actually matters for carry: if you bought a P320 in the last 4–5 years, it almost certainly has the revised FCU already. You're fine. If you inherited or bought used something older, either verify the FCU is post-redesign or don't carry it until you do. An AXG frame makes the gun nicer to shoot. It doesn't make an older fire control unit stop being what it was.

Buy the AXG if it fits your hand better and you like the weight. But that's a comfort upgrade, not a safety upgrade. Own that distinction.

I'm going to ask what's probably a dumb question, but I'm still new enough to this that I figure it's fair game.

If the AXG frame doesn't fix the FCU problem, and the real mitigation is getting a revised FCU—either by buying new or having Sig swap it—then what's the actual carry solution people should be moving toward? Like, concretely.

I get that a 2016 P320 with the old geometry is documented as defective. I get that buying an AXG frame and keeping the original internals doesn't fix that. But kept.simple's three options make sense: replace the gun, send it to Sig, or don't carry it. I'm asking because I don't know—are there people actually sending older P320s to Sig for FCU revision, or is that more of a theoretical path that most owners don't take?

Because if kept.simple's right that the realistic options boil down to "buy new or don't use it," then the AXG recommendation still seems to gloss over the fact that you're mostly just swapping out a gun that has a known defect rather than fixing the defect itself.

But I'm also wondering: is there actual data on how many civs are still carrying pre-2018 P320s? Or is this mostly an edge case—people who bought early, realized the problem, and... did nothing? Because if almost everyone who was worried enough to upgrade *did* buy new production or get it serviced, then the AXG recommendation might be less irresponsible than it reads in this thread.

I'm not trying to defend bad recommendations. Just trying to understand what the actual problem population looks like. Am I missing something about how prevalent the old guns still are?

Convert, you're asking the right question, and the answer is simpler than the thread makes it sound: there's no good P320 carry solution if you owned one before the redesign. That's the point.

Southpaw asked for documented post-upgrade incidents. I'll give you the honest answer: we don't have a clean dataset because most people who upgraded either bought new production (which came with the revised FCU) or they stopped posting about their old guns. That's selection bias, not evidence of a fix.

The settlements Sig agreed to—Army, NYPD, the civil litigation—those stipulated that the pre-2017 FCU geometry created out-of-battery firing risk under impact. Not maybe. Not potentially. The engineering investigation documented it. Sig didn't contest it in discovery; they settled on it. That verdict doesn't expire because we haven't seen a reported malfunction in four years.

Blue's department angle is the telling one. They didn't trust frame swaps to fix the problem—they pulled the whole platform. That's institutional knowledge. When law enforcement won't mix old internals with new hardware, that tells you something about what the actual defect was.

Convert's three paths—replace, send to Sig, or don't carry—those are real. Most people pick "replace," which means they're buying a new gun, not upgrading an old one. That's not a P320 solution. That's an exit.

The AXG frame recommendation glosses over exactly what you noticed: it lets someone feel like they solved the problem when they just bought a nicer-looking version of it. Sig settled because the FCU was defective. A frame swap doesn't change that verdict. It changes how the gun feels in your hand.

If you owned an early P320, the answer to "what do I carry now" probably isn't another P320. That's not Sig hatred. That's just reading what the record says.