Sig P320 light strike

[CMV]

Stock P320, about 800ish rds, factory mags it came with.

If I fill the mags with 17 AND the gun has been sitting unused for weeks, I will get light primer strikes (fail to fire) on first 2 rounds of magazine. However, after firing a few mags, I can load both mags to 17 and it will run all day long.

But this has happened on 3 separate range trips & took me until yesterday to catch on.

No grease or anything out of the ordinary - just RemOil I think. Possibly CLP, but I don't have the striker assembly or channel all gummed up with grease/crud/funk. Reasonably clean overall.

Looking at the underside of slide, it doesn't look like a full mag should be able to put pressure anywhere to cause excessive striker drag & give light strikes, but it seems like that is exactly what happens. A factory 17 rd mag only loaded to 15 will fire perfectly "cold".

When it does this, the 2 rounds it fails to fire have very light indentations on the primer - looks about like when you chamber then extract without firing a round from an AR - that little firing pin dimple on the primer from an AR going into battery - that's about what these light strikes look like. And very obviously lighter than a piece of fired brass and the indentation on that primer.

 

[CMV]

p.s. this is a post voluntary upgrade gun - it came from the factory with the new design & parts.

 

[sparkyv]

Well, that's puzzling. It may help if you can post some pictures, CMV.

 

[9mmepiphany]

No grease or anything out of the ordinary - just RemOil I think. Possibly CLP, but I don't have the striker assembly or channel all gummed up with grease/crud/funk. Reasonably clean overall.

Have you checked the Striker Block and spring?

Before you posted the above, my first thought was an over greased striker channel, because what you are describing sounds like drag on the striker.

It makes no sense at all that the capacity of the magazine affects the function.

I'd personally call SIG tech support and see what they have to say...I also wouldn't use RemOil YMMV

 

[jjones45]

I also wouldn't use RemOil YMMV

Why wouldn’t you use RemOil?

 

[ArchAngelCD]

I agree, why no RemOil? That oil is a standard IMO.

 

[9mmepiphany]

I'd used it before with confidence....after all, it was from Remington. But...

A well known custom 1911 and SIG pistolsmith, GM in USPSA and IDPA, convinced me, based on his experience over 40 years developing and working on handguns to change. His quote was, "We have it in the shop and use it as junk oil." He was basing his opinion on it's ability to lubricate, protect, and stay in place on the surfaces where it was used.

 

[Walkalong]

Years ago I used to use Remoil, like you said, it was from Remington, and other than the fact it doesn't last long, it worked. But better be ready to re-lube a bunch. I have found better products.

I too found out early on that to much oil, much less grease, in the striker channel is bad juju.

 

[CMV]

 

[CMV]

So the weapon itself not real dirty. Not pristine, but not "filthy".

The 2nd picture with paper towel....that is what came off the striker assembly. Q-tip is all I could get out of striker channel in slide.

BUT....even though that is a small amount, it is a tacky grease. Note how the Q-tip ends are pulled - that's from pulling against the sticky grease.

So I'm going to guess that even though it was a small amount, that grease is sticky enough. Even though it was 90°+ when shooting the other day, still took a mag or so to get it hot enough to not be sticky? That would explain why a cold gun has a light strikes at first.

Still at a loss why mag capacity matters at all.....but will get that assembly & channel degreased & hit with a light synthetic gun oil and see if that cures it entirely.

The only other spot that looks a little off is the wear on the corners of barrel hood. Wearing a little different than my other Sigs, but they're all DA/SA....

 

[CMV]

Took to range today and behaved itself on full mags. 150-175ish rds and no complaints. Guessing that was it. Weird....I never put any type grease on that gun, am the original owner, and it came from factory already upgraded - didn't have to get sent back in. So Sig put that gunk on the striker assembly.....

 

[9mmepiphany]

So Sig put that gunk on the striker assembly.....

Did you clean out the factory shipping grease after you bought it and before you started shooting it?

 

[CMV]

No. There wasn't "shipping grease" just a medium-heavy coat of oil in places you could see field stripping. Typical of how a new Sig (or most today) arrives in box.

But guess cleaning striker assemblies & channels will be part of unboxing now Would have never thought to pull that & do it on a new gun, nor expected such a tacky grease. I have dozen or so Sigs & none ever came with grease like that. But that & P365 are only striker ones.

 

[Zaydok Allen]

Weird. All three of my Sigs came with lots of nasty grease from the factory. All were acquired in the last three years.

 

[CMV]

P226 Legion, P365, P320, P220 (bought used, but unfired) are about 3 y/o or less for me. I don't remember any kind of grease when they came out of box. Not saying there wasn't - they could have had a quart of cosmoline each - I just don't remember anything other than oil.

But, other than the P220, they all came from same FFL and only thing he ordered for me was the legion. Others were in stock at his shop. So quite possibly the original owner for the P220 de-greased it, my FFL does that to his stock, and the Legions don't get the grease?

Also 4 1911 Sigs but > 3y/o for them. One is a C3 still NIB and checked - no grease there that I can see. Don't remember needing to de-grease those either.

 

[Robbins290]

last 3 years, i only had 2 sigs. one was packed in that white grease sig has used for a while now. and the other was a p320 that was pretty dry. in a used (restickered case). Tho i dont mind, i paid 329 for a brand new p320c in 9

 

[sparkyv]

Took to range today and behaved itself on full mags. 150-175ish rds and no complaints. Guessing that was it. Weird....I never put any type grease on that gun, am the original owner, and it came from factory already upgraded - didn't have to get sent back in. So Sig put that gunk on the striker assembly.....

Your logic is sound; looks like the sticky grease was the issue after all, CMV. It shouldn't be in the striker area, but it's a mystery how it got there... Better verify the striker condition of that P365. I was not having issues, but I did check the striker/channel on my P320 and P365 as a preventive measure. I found nothing anywhere near what you found.