STI Grip Safety Heads Up

[Joshua M. Smith]

Hello,

This is a huge picture, so I'll link it. Please let me know if it doesn't work.



It looks like they may be made only for use with triggers with built in stops, but I can't confirm that. I've sent this picture off to STI to ask their opinion.

What's going on is, after install, the trigger overtravels and allows the disconnector bar to engage the sear and would cause doubling and hammer follow.

The problem is fixed on my pistol, but I had to round file a relief in the disconnector to do it. Shouldn't have had to do this, and wouldn't have, except that I plan to get a C&S kit when finances allow.

Josh <><

[DefensiveCarry.com]

[goawayfarm]

I hope the BATFe isn't watching....you had a full auto 1911!

[Joshua M. Smith]

The situation has been rectified... and it wasn't exactly full auto. It would usually catch on the half cock notch. It only doubled a couple times.

No full auto here!

Josh <><

[dukalmighty]

The situation has been rectified... and it wasn't exactly full auto. It would usually catch on the half cock notch. It only doubled a couple times.

No full auto here!

Josh <><

Any firearm that fires more than once with each trigger pull in the eyes of the ATF is an automatic weapon,even tho your 1911 malfunctioned if some yahoo was around and confiscated it and the ATF got it to double you would be in twubble.they even claim a double barrel shotgun that discharges both barrels with a single trigger pull is an automatic weapon,glad you figgered out the problem

[QKShooter]

That extra notch in the grip safety tang of the STI grip safety is only there for ease of take-down/disassembly.

It in no way affects its function as a grip safety.

It's similar to the one being made by Fusion Firearms.

Its purpose is to permit the grip safety to be removed AKA lifted out without having to remove the mainspring housing first.

So your pistol likely has another function problem in no way related to the STI grip safety.

Just FYI.

[Joshua M. Smith]

It never did it with the GI safety.

Look at the pic - the safety serves as a trigger stop in the GI model. The STI seems to take away from that.

This has been confirmed by two gunsmiths I've talked with now.

I believe, but can't prove, that the STI safety is meant to be used only with a trigger utilizing a stop in the shoe.

Josh <><

[QKShooter]

Well, if I'm wrong I'll be sure to admit it later on.
But, I believe that you're not looking at the complete firing system.

As the trigger moves to the rear the rear trigger causes the disconnecter to pivot the sear engagement off the hammer hook.

Then the disconnecter drops down. The disconnect is loose on the pin but, the sear is a close fit.

As the top of the sear (engagement surface) moves off the hammer hooks toward the muzzle of the pistol - naturally the lower part of the pivoted sear moves simultaneously in the opposite direction.

As the hammer moves forward toward the firing pin the base of the hammer acts as a stop to the lower curve of the sear and the sear is prevented from moving any further. The pivot action is then stopped.

Once the bottom of the sear cannot physically pivot any further rearward - because its further swinging action is stopped by the hammer base - the trigger cannot physically move any further to the rear regardless of the configuration of the grip safety or the cut on the trigger stop.

Just my personal opinion on that as I understand it.

[QKShooter]

OK...just for the heckovit I just now went to Brownell's and copied their description for the 1911 STI Grip Safety. If that grip safety could only be used with certain triggers then I think it would say so in the Brownell's product description. Their descriptions are always quite accurate.
The description would state something like...

NOTE: - Can Only Be Used With Triggers That Have An Overtravel Screw.




Here it is:

1911 AUTO COMPETITION GRIP SAFETY

Mfr: STI

Performance Features Enhance Function & Reliability


Saves the pistolsmith hours of extra work with many functional, custom features built right in.
Pre-notched trigger stop speeds takedown and reassembly; insert and remove the safety without touching the mainspring housing.
Raised locator pad and sculptured beavertail ensure positive safety engagement, even with a high thumb hold.
Deeper strut channel prevents hammer strut interference.
Thicker overall dimensions allow easier blending with a wide variety of custom frames.

SPECS: CM steel, matte blue. Stainless steel (S/S), matte finish. Fits series 70. .250" (6.3mm) radius. Installation requires alteration of frame.

[Joshua M. Smith]

Hello,

It's definitely the safety stop lug. I tore it down to the frame to buff out some marks that I'd left when I was working on it and way too tired to be doing so.


Notice the travel with the STI safety. It's stopping on the mag release button.


With a GI safety, it stops well forward of where it did in the previous picture.

The sear was removed for this experiment. Everything buffed out nicely too, btw :) An old Dremel brand shoe polisher lightly sprayed with G96 saw to that.

Mr. Keefer nailed exactly what's been happening. I've tried two sears and two disconnectors known to be good, and only the filed one worked. The trigger is not being stopped where it should.

I betcha' dimes to donuts that if I put in a safety with a standard nose, it will fix the problem.

Regardless, we'll see what STI has to say.

Thanks,

Josh <><

[Rob72]

I wouldn't sweat it too much, Josh(aside from getting a safety that works for you!) Without going into all the pros & cons, 1911s are just very non-standard-standardized weapons. Some parts simply will not work in some guns, even two guns from the same manufacturer in the same run(using a part from another manufacturer.) In one form or another, most parts will require some tweaking. If you like the STI safety, you might try another GI trigger.

If your trigger is stopping on the mag catch, it may be a matter of a short-tolerance trigger- if RIA has issues with grip safeties running on the long-side, they may have remedied that by going that route. Perhaps more economical on their tooling setup.