If you're interesting in sharing some information about the P320 'Pretension' units, please consider posting in this thread. I'm not a gun smith, or expert by any means, but have completed the 320 armorer's course and sold a bunch of 320s in 2016. Will sell a bunch more in 2017 when our friends at Sig get around to making them...<cough>.

These photos compare a Gen 2 P320C-9-BSS slide with a P320C-9-BSS-PRE slide. 

If you're asking WTH a Pretention 320 is, that's what Sig is going to make now. According to Sig, the only unique parts to the Pretention over the Gen 2 are a matched slide and barrel. All other components remain interchangeable. The purpose of the "Pretension" design is to obtain tighter lockup and improved accuracy.

My observations examining the slide:

The rail [damned if I can remember the technical name] that picks the round up from the magazine and chambers it now runs full length back to the striker pocket. This is similar to the .45 cal P320 slides I've seen, but new to the 9mm/.40 cal Compact/Carry slide.

The drain hole below the extractor has been deleted.

They've added what I would call a cam surface to the right rail (rearward), but for the life of me I can't figure out its function as there is no corresponding mate on the trigger group.  If you know differently, please speak up.



FWIW: The two holes above the center rail are non-functional. They're how Sig adjusts the weight of the slide on the different models; Full, Carry/Compact, Sub-Compact and different calibers of same. Some have more of a pocket machined out of that area, some less.

There's obvious differences in the barrel hood geometry. I'm not sure if there's a difference in the feed ramp or if that's a photo artifact. Will have to check.



The barrel hood/slide lockup edges have been rounded a bit on the Pretension slides, it's subtle but enough to notice.



Additional observation. When manipulating the slide on the Pretention 320, the gun is noticeably tighter if you ride the slide down and it will sometimes stop short of returning to battery - so don't ride the slide down. In other striker fired designs like the Glock, M&P, PPQ, etc., the return spring will push the slide into battery when you stop the slide short. This design is different.

A shake or light tap resolves it, and again it happens only occasionally and only if you've deliberately and significantly slowed the slide down. At full speed, under it's own power, or in the normal firing cycle, it returns to battery every time.

I transferred the photographed example to myself, for testing purposes , and put 450 rounds through it over the weekend. It is starting to loosen up. 

In a retail or depot situation when explaining the nuances of the 320, you'll probably need to address that behavior as you would some of the other unique features.

That's the first I've heard about the pretension guns. Thanks for posting

So, the differences between the two generations are limited to the slide?

Thanks for sharing.

So is this gonna be called Gen 2.5?

so can you use a pre barrel in a gen 2?

The nice Sig rep told me (on LE Dealers line) that barrel and slide were specific to the PRE edition.  They are the only parts that are not interchangeable with their previous gen counterparts.  That is my understanding at this point.

Remains to be seen if Sig will give the new barrels a unique part number to avoid future issues.

Do have a query in to see if there's a tech update for the 320 armorer's manual.

Waiting to see what the next batch consists of to see if there's more to learn. Is this a generation 2.1 or 2.5?  Good question, maybe a 2.0.5 gen?

Thanks for posting.
Never understood guys having multiples of the same pistol until I picked up a 320.  Now I want moar of em!

Are the outsides of the slides identical, or in true Sig fashion did they make it just different enough that quality kydex holsters for the "old" 320 won't fit?

You're in the clear there. No changes to the exterior of the slide, except where the barrel hood locks into the slide. No impact on any current/future holster.

I hear you brother.

Although, and in fairness to ourselves, the platform allows us several different pistols of the same pistol that are different from each other pistol. Make sense ?

So yes, I too want MOAR.

I've finally got some Full size .45s coming in. Don't know if they're -PRE or not.  I've had these on order since April 2016.

In late spring 2016 we were told not to bother ordering the Carry .45 because the slide was undergoing a 'revision' unique to the .45, and that 9mm, .40 cal, and .357 Sig, were not involved. I can't say for certain until I actually get some in hand, but this may have been the first hints of a -PRE version of the 320.

"What we were told" may also be important to consider.

The 320 is a great platform.  If you have a gen 1 or a gen 2, you've got a great gun and I wouldn't sweat this revision. In the future, they'll probably make some -PRE conversion kits available if it really bugs you.

I believe it does. We did see an small batch of full sized FDE colored .45s escape from Sig, but we didn't see any others, of any size in .45, for the rest of the year.

One great thing about Sig is you don't have to decode a serial number. The born on date is printed in plain English right on the side of the case.

I just bought a new P320  9mm compact with a really good match up FDE more brown than tan . gun is a late build date of Aug 2016 has all the upgrades . Also picked up the L/E p320 com 9mm Sept build W320C-9-BSS-PRE with night sights and 3 mags their is a difference in slide and barrel its tighter lock up from what I can tell . mine are 2016 guns and have all upgrades slide lock,take down lever trigger spring is thicker ,new type grips .

Thank you kind sir!

I'm sure that was just an oversight on this one, they'll address it in the next Gen

I was told the 320 that have a W320 are L/E line guns and the same with the PRE on the box with it .

Whiskey code guns are LEO guns.  As far as -PRE, that could be.

I've got some 320 Carry TACOPS coming in this week that aren't W code guns. Will check the production date (should be very recent) and see if there are any changes.

Sig's 2017 LEO list should be out soon. Should be interesting to see what made the cut.

Technically, nothing.  The firearms (pistols and rifles) get a "W" prefix and Sig adds in an extra magazine for pistols. Then the guns are sold at the LEO/First Responder price.  It's a good program.  Sig publishes the products and prices on their yearly Individual Officer Purchase (IOP) program list, but their recent site redesign has made that hard to find.  New list usually comes out after Shot Show.

You can go to Sig's web site, jump over the the LEO section and then plug your zip in to find a participating dealer near you.  I'll see if I can figure out where they're hiding the IOP list now. Used to be able to download the PDF.

In the armorer's course they told us that Sig was setting up a separate production line for their LEO product. The way it's been done in the past is they stop production for a bit on 'regular' guns and crank out their W orders.

Have heard the same. I suspect workers may take a little more pride when making LEO/Mil product, but they take a lot of pride in the product they make every day. Or, at least one would hope so. I've personally never seen a quality difference between the two.

The Smith M/P line that have the L/E SKU also 3 mags , night sights all the updates are done . Sig is the same , also I was told they are test fired more rounds .L/E dist are not supposed to sell with out ID or letter head but some do cash tied up on the shelf and they need a sale .

Minor update. 

Full size .45 cal 320s (W320F-45-B) received were all made Jan 2017, fresh off the line.  The .45 is unique compared against the 9/40/357s and perhaps the design doesn't need any additional tweaking as center rail (I'm really going to have to find the correct nomenclature) was already full length. The drain hole below extractor is retained.  Hmmm, just realized I didn't check for that odd cam surface on the rail.

The .9mm Carry TACOPS received date from fall 2016 and had no pretension changes...and aren't W code. Suspect they'll get added to the 2017 LEO list though since all the other TACOPS models are on it.


Now I just need a 320 X-5 to drop into my lap. 

My W320 compact with the pre on the box has been flawless so far . I did pick up a new Carry large module black new type , in sig box its feels great but I think I need a med ,black carry size .

Picked up a full size 320 in 9mm with night sights on Sat came home cleaned it up a bit . I took it to my range and fired 50 flawless rounds today . This on has all upgrades also .A lot of places around here do not have any 320 in stock and cant get any right now .

Ran another 100 rounds through both my 320 in 9mm today Fed and Turk 123 nato they never missed a beat flawless . both guns late build dates .

Now I am really scratching my head. I have a P320 .45 compact that has the same features as the slide in the bottom of the picture- Longer stripper bar, no hole.  This pistol has a build date of November 2016.  I have 2 P320 Compact's 9mm with Manual Safety, build date- December 2016 that appears to have all the features of the Gen 2 slide shown.  When did they start with the PRE pistols.  Mine are of late manufacture.

The first PRE Compact units look to have a build date of late Sep/early Oct 2016. This revision may only be available on W prefix 320s, hoping to learn a bit more that subject shortly.

Ok  Thanks.  I am LE and Sig was not very helpful in getting a P320 with Manual Safety.  As a matter of fact, they were very elusive/vague regarding it.  This was as recent as a couple of weeks ago.  So I take it that the Gen 2 is not any less accurate???  Thanks for any info.

Right, you won't get the manual safety or the tabbed trigger except as part of a big dept/agency purchase.

It's already appreciated for its accuracy. If they've managed to improve upon that then credit to them.

If you buy a MA compliant model they have a thumb safety. 

The 2A crippled states really aren't on my radar, but took a look at the MA restricted versions and don't see thumb safety anywhere on the sheet.  Interesting if true, can you confirm for individual sale?

Yes, I have 2 in 9mm- 320C-9-bss-ms-ma.  
Looking for the .45 FCU with manual safety.  They are out there somewhere.
here is 1 of my 9mm's

They were on the 2016 IOP list for restricted states.  Came with 10rd mags instead of high caps but you could get them.  Price was the same or maybe slightly more IIRC.

IIRC MA has some sort of draconian requirement that a trigger pull weight must by a certain poundage if there's no external safety.  Sig is able to bypass that requirement by installing a thumb safety and keeping the trigger exactly the same otherwise.  RUMINT has it that you cannot retrofit the TS into a non MA complaint FCU.  

SGT45 if you don't mind snapping a few pics of the FCU close up I'd like to see if that's true or not.  If it's not true and it's an easy modification to do I'd buy the parts (if we can get them) and do it myself.  My dad really wants a P320 but he feels better with an external safety on a gun.  I tried to convince him it's not needed but when the old man digs in his heels and refuses to budge I know it's better to just go with it than continue to push the issue with him.