I need a tutorial on the lightening cuts.

Why?

When?

Anyone know?

Pix?

what?

In a prior post on this forum some time back, jljones said that lightening cuts were made on early P320 pistols to allow the use of lightweight, frangible projectiles. But the lightened slides resulted in extreme slide velocities that caused problems with extraction/ejection, so these were later modified and eliminated.

I have now seen photos documenting at least 7 different variations of "lightening cuts" on P320 slides consisting of either routed channels of various length, or cylindrical holes, or a combination of both. I have no idea why SIG resorted to so many variations. Some of the long channels routed into the bottom right side of the slide are now raising potential issues with the slide modification for the "voluntary upgrade" since they merge into the "pocket" milled for the disconnector. As a result, in those pistols the disconnector head strikes the end of the rout in a rather abrupt fashion, and the disconnector resets the trigger quite late in the rearward slide excursion.

quote:

Originally posted by pblanc:
In a prior post on this forum some time back, jljones said that lightening cuts were made on early P320 pistols to allow the use of lightweight, frangible projectiles. But the lightened slides resulted in extreme slide velocities that caused problems with extraction/ejection, so these were later modified and eliminated.

I have now seen photos documenting at least 7 different variations of "lightening cuts" on P320 slides consisting of either routed channels of various length, or cylindrical holes, or a combination of both. I have no idea why SIG resorted to so many variations. Some of the long channels routed into the bottom right side of the slide are now raising potential issues with the slide modification for the "voluntary upgrade" since they merge into the "pocket" milled for the disconnector. As a result, in those pistols the disconnector head strikes the end of the rout in a rather abrupt fashion, and the disconnector resets the trigger quite late in the rearward slide excursion.

Thanks.

I wonder if we could get a list of pix going?

I'll photo mine later and post it and maybe we could get others with which to compare?

quote:

Originally posted by pedropcola:
I have one of the long cuts that causes the late reset of trigger. I have fired it with zero problems. In fact if I handed it o you you would never tell the difference between cuts while firing. I understand the timing of reset is different. One guy on a different thread claimed a kinds of malfunctions without any specifics.

The only gripe I have heard that is potentially true is adverse wear on disconnector due to the abrupt end of the lightening cut groove.

Smarter guys than me, how does the early or late reset of trigger have any practical issues? Wear on parts will be discovered over time and become self evident. How does a late reset have any potential downside?

The guy in the other thread sent his back in. Crickets so far. I suspect Sig will send it back with no issues noted. Mine works fine. It clearly resets at a different time than my other 3 but so what?

School me, please.

Can you post a pic?

I have no idea what long and short cuts look like.

Several pictures are posted at https://sigforum.com/eve/forums...0601935/m/8770091334

Hope this helps.

TBK

Lots of pics and discussion in this thread...
https://sigforum.com/eve/forums...935/m/8770091334/p/1

Education is here.

Enjoy the read.

https://sigforum.com/eve/forums...770091334#8770091334

The linked thread has plenty of discussion about and images of the cuts if you can read through the bickering. It also contains a link to this thread which contains the aforementioned explanation of 'why' direct from jljones. https://sigforum.com/eve/forums...0601935/m/6750048524

quote:

Originally posted by pedropcola:
...
All I want is some explanation of why the disconnector engaging later and disengaging earlier in the slide cycle vice the shorter cut slides would affect safety or operation.
...

3/4Flap started this thread asking about the general purpose of the cuts along with pics, which are addressed in the links. You seem to have hijacked wanting to know about the post-upgrade functionality of slides with cuts. That confused me, as your replies made me think this was your thread.

Only one of my P320's has any kind of lightning cut, and it's a long one, on one side only. It hasn't gone in yet as it's a law enforcement individual officer's purchase, and will probably get called on much later.

I did handle one a few days ago with the same cut, that has been in for the upgrade. The trigger felt fine, but it did have a late reset. The only significant issue I can think of is for those dry firing; it's longer to pull to reset the trigger for dry fire, and if one has an empty magazine in the pistol, there's a greater chance of snagging the slide lock back. More of an inconvenience.

Didn't mean to confuse you Jbird. I have deleted my posts. Enjoy your pictures.

Can these lightening cuts be arranged in any chronological order or according to serial number?

Forgot to ask: What do the underside of current production guns look like?

Good grief, I could hide a handfull of small change in all the holes milled in the bottom of my 320 slide.

Are such slides problematic? I've never had any trouble with it, but I only have some hundreds of rounds thru it.

And a comment. I enjoy reading about the history and production of firearms almost as much as using them. And to those who are disturbed by the changes to the 320 during its relatively short production life, don't take it personally. EVERY firearm that lasts is subject to changes in manufacturing, design, improvements, etc. Sometimes more efficient methods {AKA cheaper} of production are found and incorporated into the series. other times problems are found that were not anticipated. So the mere fact that there are changes in the 320 doesn't bother me one bit. I have an older-ish one. It is carved up inside like a Christmas turkey. If those cuts don't cause issues, I don't care that they are there, even if they serve no current or foreseeable purpose.

Having said that, I understand turtlebaykid's concern. If I could get a free, updated slide, I would.

As for the actual problem, just leaning hard on intuition, I do not see how a FULLSIZE gun's performance could be hindered by these cuts. We have been told that Compacts have been troubled by these cuts. OK. But a Fullsize? Granted, it is comparing apples to oranges, but the mass of a FS slide is I suspect, heavier than an uncut Compact. So until I read of repetitive, significant troubles or experience them myself, I'll shoot the thing and use it and trust it.

Here's mine. You guys that have concerns, tell me what is bad about this gun {if anything}:

This message has been edited. Last edited by: 3/4Flap, December 01, 2017 07:42 PM

quote:

Originally posted by 3/4Flap:
Can these lightening cuts be arranged in any chronological order or according to serial number?

I have read several times on here that Sig more or less just grabs 320 FCUs from a stack as needed, and they do not reserve particular S/N ranges for any particular combination. Meaning one S/N might be a subcompact .40 and the next number up might be an X5, for example. I'm sure it's a little more organized than that, but apparently we won't have much luck trying to track ranges the way we do with the Classic models.

You could probably come up with a decent chronological progression of the slide cuts based on everyone's "born on" date, if you really wanted to put in the work.

quote:

Originally posted by 3/4Flap:
As for the actual problem, just leaning hard on intuition, I do not see how a FULLSIZE gun's performance could be hindered by these cuts. We have been told that Compacts have been troubled by these cuts. OK. But a Fullsize? Granted, it is comparing apples to oranges, but the mass of a FS slide is I suspect, heavier than an uncut Compact. So until I read of repetitive, significant troubles or experience them myself, I'll shoot the thing and use it and trust it.

I'd have to agree, considering the 320-X5 has the visible lightening cuts, as does the VTAC and even the X-Carry. Although the X5 is a bit oversprung as well, the combination they put together makes it extremely flat shooting!

I have a late 2016 build L/E 320 W-320-com-pre in 9mm and its been flawless a real tac driver, It has no cuts and it also has the full length shell stripper in the center , I think it keeps the other rds down further so no jams . I might not send it in I did get notice for my other 320 but it was traded by the time I got it . I kept the L/E package .