Sig P320 "failed FBI test miserably"

[LockedBreech]

I think people are talking about different things or at least not defining things the same way.

Again, we’re talking about tilting barrel locking, short recoil systems. There are two different, but coupled, things happening. There’s “short recoil” where the barrel and slide travel rearward together, and then there is “tilting barrel locking/unlocking”. There is a difference between the slide being retracted a bit and wedging stuff between the breech face and the barrel. The former is, at least potentially, during the short recoil portion of the operation and the latter is 100% absolutely after it and possibly into tilting barrel unlocking.

Perhaps to some, out of battery means “slide not fully forward”. To others, perhaps it means “breech face not in contact with the barrel”. Those two things are different.

This idea has been nagging on the back of my brain as I've read the thread and I wasn't able to put my finger on it.

Is a good illustration of this separation the PX4/Cougar series? I was just messing with my Cougar 8000F thinking about this. The barrel and slide travel together briefly for the short travel of the locking lug in the barrel groove, and then the slide continues back at the end of the lug's travel. So that's a short recoil action but NOT a tilting barrel action, yes?

[DpdG]

I could have been more clear in my previously explained experiment- based on my pencil launching, it appears my pre-recall P320 would fire at any point during the "short recoil" phase. Within the margin of my measuring abilities, it would cease to launch pencils very early in the initiation of the "barrel tilting" phase. The deceptive part was the striker would still be released well into the "barrel tilting" (even as the barrel was not totally in contact with the breech face) but it was captured by the striker block and would not hit a primer.

In summary- my sample of one pre-recall P320 would likely fire if the slide was not fully forward, but not if the barrel was no longer in contact with the breech face. My post recall ones, which do not have the problematic lightening cuts in the slide, seem to disable the striker even earlier, before reaching the "barrel tilting" phase.

[0ddl0t]

More videos:

First is running various feeler gages in a Glock 17, VTAC M&P, Ruger American and a P320 Compact and P320 X5.

Note that they'll all pretty much pop a primer at some point without the slide being seated 100%. The feeler gages don't really do anything other than measure the fit of the barrel hood. Still, it does give a more consistent metric rather than just trying to ease the slide back and forth to find the sweet spot that holds the slide in enough or out enough to pop a primer.

Note that both 320's will close, with a little pressure, on the .004" feeler gage.

Very cool video, thanks!

I wonder if this is intentional so your pistol will still fire if you jam the crown of the barrel into a wall/perp and it pushes the slide rearward slightly.


As for the FBI test results, I'd love to see them too. But looking through the official solicitation, it seemed like the Glock had a lot of standard features the FBI wanted:

C.3.5 Contractor may purchase components for the firearm from other sources; however, the Contractor shall be the primary manufacturer of the pistol. Contractor may not use or employ any subcontractors without the prior approval of the COR.

I don't think Glock uses any subcontractors, but Sig uses many interchangeably.

C.4.3.g The follower shall move freely in the magazine body without binding and shall position each round for positive feeding.It is preferred the follower be a high visibility color (orange, red, yellow, etc.).

I don't think Sig offers high viz followers

C.4.3.h Magazines shall have witness holes which will permit viewing the number of rounds in at least 5 round intervals.

It is preferred witness holes exist for each cartridge contained in the magazine starting with cartridge number 4 and showing every cartridge contained in the magazine thereafter.

Sig magazines don't count individual rounds

C.4.8.d The slide stop lever should be designed such that it is unlikely a shooter will inadvertently engage or override the control during normal firing.

For some shooters, Sig's require an altered grip to avoid slide lock override.

C.4.14.b Characteristics

Front and rear sight must allow the shooter to acquire the proper sight alignment rapidly.

The proper alignment of the sights will be consistent with “equal height, equal light” sight alignment. The information line for the FBI is the top of the metallic sights.

Figure 2 below represents 25 yard point of aim/point of impact:

Sigs use a combat hold, not a center hold, though you'd think they could make the change just for FBI guns.

C.4.15.d Two acceptable methods of accommodating for different hand sizes are:

Multiple Frame Sizes
Two alternate sizes must be available and supplied with each pistol.

Grip/Frame Inserts
Two alternate sizes must be available and supplied with each pistol.

It is required the size of a frame or insert be marked on an exterior surface (e.g., “M” for medium, “L” large) for rapid identification without disassembly.

I suspect the FBI considers Glock's interchangeable backstraps much easier to deal with than swapping grip modules.