P320 Open division components?

[Rudukai13]

Quick backstory; For a while now I've been pondering the thought of putting together a budget Open division pistol using a polymer/striker platform. I'd love to use a P320 as the base - I'm an unashamed Sig-whore.

My question is - What's the likelihood of seeing support from either Sig or aftermarket sources to build a decent Open gun on a P320? I'm referring to things like magwells, comps, frame-mounted optic bases, etc. similar to what we've seen for Glock/M&P/XDm guns in recent years? I would think the increased modularity over the other listed platforms would lend the P320 to being very easily supported with various bolt-on or very slightly fitted parts...?

Edited June 26, 2015 by Rudukai13

[JAFO]

I'd guess slim to none from Sig directly. There's virtually no support for the X5 Open model in the US, and that's been around for a long time. There are some smiths milling 320 slides for MRDS, and some aftermarket supplier will probably find a way to adapt a magwell, since that could be used in Limited as well.

I've never seen anyone run a frame-mounted optic on a polymer frame striker pistol. How does that hold up with the frame flex?

[Rudukai13]

JAFO, most optic "bridge mounts" for pistol tac rails aren't much more than a gimmick because they don't hold their zero very well, as you stated due to the flex of the polymer mounting area. A few companies, however - one such example being Carver Customs - Offer true competition-grade mounts that not only connect to the tactical rail, but also are braced using a pin through the actual metal frame insert in the pistol grip. This stabilizes the mount much more effectively than only anchoring it to the polymer picatinny rail, and makes it stable enough to be used for serious competition. A picture of one of Carver Customs' mounts is attached. For reference, this is the style of optic mount that KC Eusebio used on his Open Glock(s).

The reason I think a mount like this is at least feasible for the P320 platform is the take-down pin - It's very similar to the one used by S&W on the M&P, and Carver Customs uses this point as the secondary anchor for their optic mount, replacing the pin with one that's been drilled and tapped to accept a screw, which anchors the bridge mount.

Edited June 30, 2015 by Rudukai13

[JAFO]

Not sure if using the takedown lever would be feasible with the 320. I don't have one (yet), but it's my understanding that there is a slot in the takedown lever pin that the takedown safety lever in the FCU moves into to allow the pistol to be reassembled. It might be difficult to time a screw to make a slot line up just right for that safety lever to reengage.

Here is a picture I stole from a Sig armorer on Sigforum showing the chamfered portion of the safety lever that engages with the takedown lever pin on reassembly.

[Rudukai13]

Perhaps a picture of the actual M&P mount will help to better explain. It's my belief based on research and study of the mechanism (though I may still be wrong, admittedly), that the timing of the screw that attaches the bridge mount is independent of the angle of the take-down lever. Basically CC has created a floating attachment point that shares the same geography on the pistol as the take-down lever, but still functions independently from it.

Again, if anything I've stated here about the CC mounts is incorrect, please do correct me - I'd rather be corrected and provide others with helpful information than incorrect advice!

[racingjoe27]

Unless this is going to be used for steel matches, I think a better question would be can a p320 handle 9 major?

[alma]

Unless this is going to be used for steel matches, I think a better question would be can a p320 handle 9 major?

Good question. My Open Glock only went a few thousand rounds before the breach face cracked.

In the next month or so I should have an extra slide and I still have some Open Major loads that I can test with.

Edited July 1, 2015 by alma

[alma]

I think the modularity does make for some very interesting options.

Without getting into details I will say that the hinted "Competition" model that is now actively being developed should be more suitable to building up a striker fired open gun.

In the meantime it looks like Scott Springer is doing some magwell designs that would be installed directly on a modified grip frame module so instead of adding the magwell you would swap out the grip frame. Given the price of grip frame modules it makes it easy to play around with opening up the existing magwell, adding weight, and experimentation with grip texture treatments.

For Optics the easy route is using a P320 Romeo that has the slide mounted MRDS.

For a frame mounted optic the cut for the Takedown lever safety is not that difficult to make and it shouldn't be an issue to make an alternative one if you want to go that direction. You could, of course, modify a grip frame to permanently mount directly to that but I agree that using a point that contacts the frame FCU might be a little better. The slide to frame fit isn't bad for a striker filed gun but if you want it tighter then Grayguns has welder up and tightened the slide to frame fit for customers who are looking to further improve the already above average accuracy.

For magazine extensions you should be able to use M&P extensions one the grip frame module has been modified for clearance. There are a few 140 mm extensions specifically designed for the P320 now.

Now we need to find a comp. The SIG threaded barrels use a more obscure threading pattern so this is one of these long pulls in the tent in my mind.