X5 Legion accuracy

[HOGRIDER]

On 8/9/2022 at 6:06 AM, tim_w said:

A gunsmith fit barrel allows you to fit that lug and the hood.  This locks the barrel in a repeatable position on in battery lockup.  If it has a loose hood and very worse the lug is not sitting flush on the block you will get variation in lockup and as you pull thru the trigger. Bullets go shotgun or shift with fliers

 

Supplied with the Bar-Sto GS Fit barrel:

 

 

[bimmer1980]

On 5/25/2022 at 4:01 AM, tt350z said:

 

The vice jaws pressed on the top of the rails and bottom of the FCU. The rails did spread a little bit as it was pressed down since its an unsupported U-shape. I did have to spread my front rail more than the rear rails as it was sloppier. I just filed/polished the side of the rails until the slide cycled smoothly. Now I have very minimal vertical movement and basically zero lateral movement.

 

I was just shooting factory 115g Blazer Brass. 124g Prvi grouped about the same. Didn't notice a change in group size while shooting standing unsupported except for snappier recoil.

How did you clamp the rear rails? Somehow i find that the nose getting into the grip on the rear makes it hard to press the rear rails down correctly. 

[tt350z]

8 hours ago, bimmer1980 said:

How did you clamp the rear rails? Somehow i find that the nose getting into the grip on the rear makes it hard to press the rear rails down correctly. 

Yes, I had to completely disassemble the FCU to clamp down on the back rails. Front rails can be pressed down without disassembly.

[bimmer1980]

16 hours ago, tt350z said:

Yes, I had to completely disassemble the FCU to clamp down on the back rails. Front rails can be pressed down without disassembly.

Perfect, thanks a lot ! 

[Zincwarrior]

6 hours ago, bimmer1980 said:

Perfect, thanks a lot ! 

You should do a youtube video or such about how to do it. It sounds like a good fix that would literally save viewers hundreds of dollars. 

[USP45]

On 8/16/2022 at 8:16 AM, tt350z said:

Yes, I had to completely disassemble the FCU to clamp down on the back rails. Front rails can be pressed down without disassembly.

Once you clamped the FCU and squeezed it did it flare the sides enough to make the outer portion of the tabs rub against the slide? I did similar to a Glock and while it stopped the vertical movement in the slide to frame fit I then had to lightly file the outer rails as they had spread just enough to rub on the slide where they had spread a little. My X5 has a good barrel to slide fit, but the slide definitely has so.e vertical movement.

[Tampa-XD45]

Has anyone else tried tt350z's "squeeze the FCU rails" idea?

 

Is it to clamp the two areas with green arrows in the FCU pic below?

 

[mpeltier]

I have and it works. I didn't even know about this thread when I started another thread on the same subject as tt350'z did. I actually couldn't get the rails to squeeze in a vice. I had to carefully hammer them down to the dimension I wanted then I had to refit the rails to the slide with a file. Like His mine grouped like 6-8 inches at 15 yards. Totally unacceptable. When I was done groups were under 2" at 15 yds, and no flyers. It's not a barrel to slide issue.

 

I just don't understand why SIG uses a stamped pos part for the fcu housing on the P320. They at least got it right with the P365 and machine a more precise housing for it. Both of my P365's were far more accurate than my P320.

[lawman]

I used the vice clamp method on my FCU as well with success. I took virtually all of the vertical play in slide to frame fit out, I only left a little bit of lateral play for reliable function. Had to file down / refit the FCU rails to slide rails afterwards, otherwise the slide would bind terribly on the FCU rails. However, it had a rather cosmetic effect, I get pretty much the same groups as before, with slow fire at 25m I can do about 3" if I do my part, more or less the same as before. My barrel to slide fit was good from the get-go, no discernible play when I push down on the barrel hood. Honestly the biggest effect on the size of my groups was achieved by a trigger job - I managed to get down to 2.5lb with about 3.5mm reset and buttery smooth pull, pretty goodtrigge if I say so myself. But for some reason, I am still less accurate with my legion at distance of 25m or more than with a Glocks, XDMs or 1911/2011s for some reason. All in all, I wish the legion had a bit more accurate barrel with a tighter rifling (I found out it shoots best with .358" bullets, my other 9mm pistols are good with .357"), but for the intended purpose (IPSC shooting), it is accurate enough.

[Foxtrotx1]

If the FCU really is the issue, then why not swap FCUs around and see if accuracy improves. If just the x5 FCUs are showing this issue, then that's the answer. If accuracy is bad with all FCUs then the slide or barrel would be suspect. Surely someone around here has a legion stock gun and a non legion stock gun to try. 

 

I mention this because plenty of other p320s stock from sig seem to be getting decent results. There's always a chance that it's a combination of factors and everybody is seeing different results depending on what they fix. Gun might not like 147s driven slow, slide lockup might not be tight (low power spring, loose dimensions) FCU could be newer, older, fixed in the recall etc. 

Edited June 11 by Foxtrotx1

[mwx40x40]

On 9/24/2020 at 9:05 AM, punisher911 said:

I came here for accuracy answers to my X5 Legion... I was a 25yd bullseye shooter and can cloverleaf groups at 7-10 with almost any handgun... Except my Legion...  easily the fastest gun I own and I use it in Carry Optics USPSA... but man does it group poorly. Sure, at 7yds it is "good enough" for USPSA, but when we start getting 20-25yd targets, it just doesn't cut it. Was hoping to find some answers, but I see it is much more common than word of mouth would let me believe. I've tried 115, 124, and 147gr bullets of various power factors. Nothing groups well. Was contemplating a barrel change. Has anyone tried that? Has anyone figured out the secret to improving the accuracy of these?

 

X5 Legion, Sig Romeo 1 Pro, tungsten guide rod, tungsten grip slug, thumb rest [generic] *thumb rest [generic]*, Grey Guns adjustable trigger. #12 spring

Following this thread hoping to find some answers. I agree I have been sorely disappointed in the accuracy of mine as well 

[RangerTrace]

I think I already posted this somewhere in here, but GGI has this figured out.  Both of my 4.7" GGI pistols will shoot 1.5" groups at 25 yards with 124 grain ammo.  They are just as accurate as my Staccatos.  I think it's the barrel fit that does it.

[GJM]

46 minutes ago, RangerTrace said:

I think I already posted this somewhere in here, but GGI has this figured out.  Both of my 4.7" GGI pistols will shoot 1.5" groups at 25 yards with 124 grain ammo.  They are just as accurate as my Staccatos.  I think it's the barrel fit that does it.

My wife and I have a number of GGI 4.7 inch uppers, and as I. have reported previously, they shoot amazingly well. I think the special sauce, though, is in the fitting of the slide, and not the barrel.

[AZ123456]

As someone that's been down this rabbit hole for awhile now,  what are you referring to when you say fitting the slide? TIA.

[GJM]

27 minutes ago, AZ123456 said:

As someone that's been down this rabbit hole for awhile now,  what are you referring to when you say fitting the slide? TIA.

 

When the original 320 X5 pistols came out, they were accurate. That changed with the 320 Legion. With the X5 pistols, there was a hitch as the slide went fully into battery, and that took some break in rounds for the pistols to be reliable. That hitch disappeared with the Legion, and accuracy went down hill.

 

I know someone that had multiple Bar Sto barrels fit, and that didn’t improve the accuracy. The work around we settled on, was buying legacy X5 slides, and combining that with everything else on the Legion. Accuracy was fine.

 

The GGI slides, especially the 4.7 Lockwoods, have shot great for us, especially with PMC 124 where I have gotten near one hole groups at 25 yards. Originally, GGI used a OEM barrel, later a Faxon, and accuracy didn’t change — all good. Apparently someone in Oregon has been “fitting” the Legion OEM slides, and getting similar accuracy. All of this makes me believe it is a slide and not a barrel issue. 

[AZ123456]

13 minutes ago, GJM said:

 

When the original 320 X5 pistols came out, they were accurate. That changed with the 320 Legion. With the X5 pistols, there was a hitch as the slide went fully into battery, and that took some break in rounds for the pistols to be reliable. That hitch disappeared with the Legion, and accuracy went down hill.

 

I know someone that had multiple Bar Sto barrels fit, and that didn’t improve the accuracy. The work around we settled on, was buying legacy X5 slides, and combining that with everything else on the Legion. Accuracy was fine.

 

The GGI slides, especially the 4.7 Lockwoods, have shot great for us, especially with PMC 124 where I have gotten near one hole groups at 25 yards. Originally, GGI used a OEM barrel, later a Faxon, and accuracy didn’t change — all good. Apparently someone in Oregon has been “fitting” the Legion OEM slides, and getting similar accuracy. All of this makes me believe it is a slide and not a barrel issue. 

Appreciate the explanation. I ended up selling my two legions and buying used original X5"s off gunbroker. I added the txg module and GG trigger to them.  This was just prior to the GG slides being available or I would have gone that direction. 

[GJM]

3 minutes ago, AZ123456 said:

Appreciate the explanation. I ended up selling my two legions and buying used original X5"s off gunbroker. I added the txg module and GG trigger to them.  This was just prior to the GG slides being available or I would have gone that direction. 

Osage used to sell just the legacy X5 slides, and we bought a number of them prior to the 4.7 GGI slides being available. Seemed unusual a 3.1 inch 365 was more accurate than a 320 “Legion” competition pistol. 

 

 

[AZ123456]

45 minutes ago, GJM said:

Osage used to sell just the legacy X5 slides, and we bought a number of them prior to the 4.7 GGI slides being available. Seemed unusual a 3.1 inch 365 was more accurate than a 320 “Legion” competition pistol. 

 

 

I did see the slides for sale at the time but hadn't figured specifically what was causing the accuracy issues so went with the entire gun.  

[Foxtrotx1]

I'd still like to see some mechanical rests used for an analysis of a few models of x5s. There's so much back and forth, and variables that something isn't making sense. 

[WxGuy]

I have a 9 day old X5 Legion, stock barrel, and it groups nicely.  I'm sure a gunsmith fitted barrel to slide, etc., would be slightly better.