STI Problems - Help Needed

[opsoff1]

Coworker of mine has an STI Eagle 5.0 in 40cal. 5" gun, bull bbl, (no bushing) and 1 pc reverse plug guide rod. I believe all of this is OEM from STI.
Problems have started where the slide will lock open with 1, 2 or 3 rounds still in the mag. Intermittent and seems to happen regardless of ammo.
Ammo types are factory 165 & 180 gr FMJ.

Background: This pistol has and I'll quote my bud; "tens of thousands of rounds through it". He shoots the snot out of it. (200rds /wk x 10 yrs) All the springs in it are orginal - as in they have never been changed.
Just a guess, but I'd say they're a bit tired. The mags have fresh springs in them this summer. I have checked the plunger tube spring and plungers - GTG there.

My thoughts are to first, get fresh springs in the gun - recoil (14lb) main (21lb) and firing pin spring as I suspect that the slide is cycling so hard that it is causing the slide latch to engage.

As far as the mags go - the followers look to be ok and the feed lips seem to be intact. The mags (15rd'ers) all function fine.

Am I missing something? Anything else I need to look at here?

TIA

[theJanitor]

Who the heck buys a boutique gun, shoots it for ten years and NEVER changes springs? Tell your friend to get that gun sprung to factory specs, then evaluate. The best way to get guys like these on a spring replacement schedule is to change the recoil spring when he cracks open a new case of ammo. It might be way too frequent than needed, but I've never seen a gun that didn't appreciate fresh (and correct) springs.

[opsoff1]

LOL - I wish I had a picture of my face when I asked him when the last time he changed the springs and he said never. Shock is putting it mildly....
I am ordering him 5 recoil springs so he'll have them.

He is a retired high end SOF guy - when they broke stuff ....well it wasn't something they had to worry about.

Thoughts on the slide locking open?

[jbjh]

STI should have a schedule for changing springs out. Wolff Springs has good info/advice as well.

[sua175]

LOL - I wish I had a picture of my face when I asked him when the last time he changed the springs and he said never. Shock is putting it mildly....
I am ordering him 5 recoil springs so he'll have them.

He is a retired high end SOF guy - when they broke stuff ....well it wasn't something they had to worry about.

Thoughts on the slide locking open?

Lol so I guess SOF dudes don't understand that parts wear out, especially springs? I came from the SOF community and I understand perfectly that weapons have to be serviced in order to work properly.

Im kind of impressed that the gun even cycles with over 10k rounds on a original guide rod spring, concerning spring changes I always go off the round count provided by the manufacture.

[sinister]

New recoil spring every 1000-1500 rounds. Worn springs affect cycle timing (especially in a "Whippy" .40).

[opsoff1]

Lol so I guess SOF dudes don't understand that parts wear out, especially springs? I came from the SOF community and I understand perfectly that weapons have to be serviced in order to work properly.

Im kind of impressed that the gun even cycles with over 10k rounds on a original guide rod spring, concerning spring changes I always go off the round count provided by the manufacture.

sua175 Please don't take it as a knock on the community - I work with them everyday. I know he understands that stuff wears out - the comedy of it was that he didn't have to worry about it. I still suspect that springs were replaced, but he didn't pay attention to it as the gun ran. He is kind of like a race car driver - doesn't know or care to know how/why the car runs - he drives it. Kinda the same here. I'm the complete opposite - I need to know how/why of everything. FWIW - he was a breacher - had his bell rung a few times so his memory isn't exactly pristine. Trying to help a brother out here.

He's getting all new springs and a hefty handful of spares - we'll see how that pans out for the problem. I showed him an older 1911 with a cracked frame from battering / recoil spring so worn out that it was 2" shorter than a new on - he gets the point now.

So - I'll refer back to my original post - I suspect that the slide is cycling so hard that it is causing the slide latch to engage.
First order is to get fresh springs in the gun - recoil (14lb) main (21lb) and firing pin spring.
I'll evaluate after this - but.. Anything else I need to look at here?

[sinister]

Check his extractor tension and maybe his firing pin stop (they can crack from the hole to the 7-8 o'clock corner if not radiused). Maybe his magazine springs, otherwise the guns will keep shooting.

[Tigereye]

Springs will probably fix it. If not, you can also find good ideas at brianenos.com

[Co-gnARR]

If possible, will you post photos of the old vs new springs? Also any details of the gun itself if there are signs of excessive wear would be great educational material for those that ignore maintenance schedules.