P365 Replacement Slide Issues

[ReluctantDecoy]

I have a P365 free state that I had swapped the grip module to a P365XL grip. Ran flawlessly. I later bought a P365 slide with a red dot cut from Sig. Actual Sig OEM slide with full assembly. When I first installed the slide, I noticed it felt, for lack of a better term, "sticky" in range of motion. Rack it back and let it go, and the slide seem to have some sort of friction that would prevent it from easily going back into battery.

I just assumed it was tight from the factory and required break in. Racked it hundreds of times at home. Brought it to the range and while it shot the first round, the action would not fully return to battery. It would get stuck halfway home, requiring a light tap to the rear of the slide to send home. This continued for a couple mags, each time it just require a very light tap on the back.

Took it home, broke it down and lubed the sh*t out of it, then put it back together and continued to rack it. Slightly better, but still some odd resistance mid-cycle. Put the old slide back on and it racks fine. Compared the two slides and I can't immediately see any difference that would cause this. Any ideas of what I should check? Sig's customer service said to bring it to NH for review. I just might, but wanted to know if y'all had any other advice. Been sitting on this for a while, but just been too busy to get around to it.

 

[paul73]

1) sig sucks
2) instead of lube - you can use some metal polish on rails, and rack it back/forth until it increases the play between surfaces.

i would return that slide and tried other one before permanently increasing tolerances that can affect the play on the other slide that is not having issues. new slide may also be warped (slightly) and you do not see it.

 

[ReluctantDecoy]

1) sig sucks
2) instead of lube - you can use some metal polish on rails, and rack it back/forth until it increases the play between surfaces.

i would return that slide and tried other one before permanently increasing tolerances that can affect the play on the other slide that is not having issues. new slide may also be warped (slightly) and you do not see it.

Huh...the possibility of warping didn't occur to me, mostly because I paid through the nose for this slide. I'll have to break out the calipers tonight.

And yes, I probably won't change tolerances just to make this work, so I'll probably just end up putting the old slide back on. I was just curious if there was something oblivious I might have been overlooking.

 

[paul73]

Huh...the possibility of warping didn't occur to me, mostly because I paid through the nose for this slide. I'll have to break out the calipers tonight.

And yes, I probably won't change tolerances just to make this work, so I'll probably just end up putting the old slide back on. I was just curious if there was something oblivious I might have been overlooking.

check with sig. on some slides - like below, the worst thing can be a wording: 'Oversized, will require fitting to your frame.'
as the fitting of those rails - well, it is a pita.

CZ Shadow 2 slide

Shadow 2 slide, 9mm Oversized, will require fitting to your frame. Slide only. Small parts, barrel, sights are not included. This is slide only for Shadow 2

czcustom.com

 

[drgrant]

#whyidontplaymixmastergames

It's always better to just buy another gun.

 

[paul73]

#whyidontplaymixmastergames

It's always better to just buy another gun.

true, but, to expect such issue with a p365 - it is not exactly a top of the line competition all steel thing.
but, i guess we all got too used to glocks and how it all 'just works'.

 

[drgrant]

true, but, to expect such issue with a p365 - it is not exactly a top of the line competition all steel thing.
but, i guess we all got too used to glocks and how it all 'just works'.

I am mostly a glock guy and I won't do it with glocks either. I've seen a lot of shitty mixmaster glock builds too. The only exception id ever make is for a P80, otherwise it better be native.

 

[ReluctantDecoy]

#whyidontplaymixmastergames

It's always better to just buy another gun.

I mean, I guess I have to agree with this now. But defeats the entire purpose of Sig's "modular" mentality of this platform and the P320.

 

[paul73]

I am mostly a glock guy and I won't do it with glocks either. I've seen a lot of shitty mixmaster glock builds too. The only exception id ever make is for a P80, otherwise it better be native.

i have 2 g17s and g34 - all interchangeable just fine. not a single issue.
even stupid g19x slide did fit, only did not work.

 

[drgrant]

i have 2 g17s and g34 - all interchangeable just fine. not a single issue.
even stupid g19x slide did fit, only did not work.

A lot of my guns interchange and work. It's still stupid, though.

 

[drgrant]

I mean, I guess I have to agree with this now. But defeats the entire purpose of Sig's "modular" mentality of this platform and the P320.

Part of the problem is, when they QC the slide and barrel, do they actually test fire it on a few frames? My guess is "probably not". Then again, these days the whole guns might not even be test fired anymore.....

 

[TJ4]

did you try the new slide on the regular 365 frame that came with it to see if that works? Not sure what that will tell you, but, you would have confirmation that it doesn’t work on 2 frames I guess for what that’s worth.

 

[ReluctantDecoy]

Part of the problem is, when they QC the slide and barrel, do they actually test fire it on a few frames? My guess is "probably not". Then again, these days the whole guns might not even be test fired anymore.....

I'm wondering if they even bothered to spot measure after machining. Something is off. Ever so slightly so, but still off. And I'm not sure if it's this new slide or my existing FCU at this point, but I'm guessing if it is my existing gun, at least they checked slide function after assembly.

 

[ReluctantDecoy]

did you try the new slide on the regular 365 frame that came with it to see if that works? Not sure what that will tell you, but, you would have confirmation that it doesn’t work on 2 frames I guess for what that’s worth.

Didn't try that. Same FCU, so I didn't think the frame would matter. Would it? It doesn't touch any part of the slide.

 

[BTSDOG]

Try swapping recoil springs ??

 

[ReluctantDecoy]

Try swapping recoil springs ??

Same recoil spring. The slides should in theory be identical save for the red dot cut in the new slide (and the fancy "X" engraving). The new slide came complete with slide guts and red dot, but I'm re-using the old barrel, recoil spring, FCU, and frame.

 

[jct61765]

Anything machined has tolerances. The slide may be on the low side, while the frame is on the high side. I would bring it back and bring your frame. I highly doubt they would care if you tried it fitting one at the pro shop. They would probably do it for you.
There's no way the slide is warped. The slide blanks are heat treated before machining.

 

[ReluctantDecoy]

Anything machined has tolerances. The slide may be on the low side, while the frame is on the high side. I would bring it back and bring your frame. I highly doubt they would care if you tried it fitting one at the pro shop. They would probably do it for you.
There's no way the slide is warped. The slide blanks are heat treated before machining.

I assumed tolerances would come into play, but maybe held out too much hope that Sig, offering a modular FCU system, would ensure that it was in fact modular. That's why I thought maybe I'm missing something stupid and obvious, but I think it's just a bad cut.

 

[Wickedcoolname]

Reminds me of the ax my father had for over forty years. Best ax ever made, he said. Lasted over 40 years of chopping wood.
Replaced the head twice and the handle three times. Otherwise, all original.

 

[ReluctantDecoy]

Reminds me of the ax my father had for over forty years. Best ax ever made, he said. Lasted over 40 years of chopping wood.
Replaced the head twice and the handle three times. Otherwise, all original.

Little different. I'm trying to build the gun that is available now, but with the FCU from the gun I purchased before these newer parts were available. That said, drgrant has the right idea. Just should have bought a new gun to go along with my existing.