1911 safety pops up on firing

[Rmeju]

My ambi safety broke on my 1911 and I needed a new one. I was going to go to the smith, but YouTube made it look simple enough, so I thought I'd give it a try.

I thought I was going to need to fit it, but it went right in, so I didn't do any actual filing. Everything looked and felt fine at home: the safety moved up and down fine, and prevented the trigger from actuating when engaged. But at the range, under fire, every round I send reengages the safety, which is obviously a problem. This does not happen when I manually cycle the slide.

My only thought is that the safety came filed down *too* far, permitting the safety to move under recoil, but I'm not an expert, so I don't really know.

I was hoping my fellow high roaders might be able to enlighten me. Any help would be appreciated!

 

[mag1911]

Did the old safety have a detent to catch the safety plunger? Does the new safety have the detent?

 

[nettlle]

You may need a new spring in your plunger tube.

 

[Stony]

You might have to deepen the detent hole where the spring plunger rides on it. Normally when this happens, it is due to someone bumping it with their thumb upon firing, but you might just need to alter the safety where the plunger engages it more. It sounds like the safety is working correctly other than not having enough spring pressure to hold it in place, which is easily fixed with a little dremel work.

 

[BBBBill]

A repost of something I posted elsewhere. Focus on the part about fitting to the frame -
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This is a little more info than you asked for, but others might benefit.
The safety must be fit (as needed) to the frame, the slide, and the safety detent plunger as well as the sear.

First, examine your safety to insure that the pin is straight and square to the body of the safety. I've seen some pretty bad ones come out of the package. Either straighten it or return it for one that is square to the pin/body. You may have to stone the back of the shield (flat portion that rides the outside of the frame) to eliminate any casting irregularities that will prevent it lying flat and/or scratching your frame. Do not remove the radius at the root of the pin.

I also check the diameter of the pin holes in the frame and grip safety vs the pin diameter on the safety. Pin diameters I've seen vary as much as .009" (Wilson is noted for being large) and can effect the function of the grip safety at the extreme ends of the spectrum as well as cause friction drag on the thumb safety if there is not enough clearance. If the thumb safety drags/binds when inserted through the frame and grip safety with nothing else installed, you've got to address that up front.

Then, strip the frame of all parts so that you can insert the thumb safety by itself and observe any interference. Insure that you remove the safety detent plunger assembly. You want no possible resistance from anything except the frame itself. Fit to frame to insure that it is seated fully and smoothly moves fully from on safe to off safe. You may find that the notch on the underside of the safety lug is too narrow and binding on the frame window. Edit - Additional step: It would be good to add the hammer and sear pins here and check again for drag/binding. I stone the tops of the pins to remove any machining artifacts that might scratch or drag on the back of the thumb safety. I like to leave them a couple thousandths proud of the frame to prevent the TS from rubbing/scratching the finish. -End edit
Relieve the face of the lug to widen the notch ever so slightly with a safe side needle file if needed. Remove only enough to allow the safety to clear the "window ledge" and drop all the way down. .0005" -.001" is plenty. More is too much.

Then install the hammer/sear/disconnector (with mainspring/mainspring housing and sear spring) and fit the safety to the sear to insure no (absolute zero) movement of the sear/hammer while on safe. Insure that the safety is fully blocking the sear while in the up position with the slide on. Do not fit the safety to the sear with the slide off as the safety can sometimes overtravel upwards without the slide resulting in a poor fit to the sear when fully assembled. Check fit of the safety upper blocking surface in the slide notch while on safe. Adjust fit as needed.

Then remove the hammer/sear/disconnector again, reinstall the detent plunger assembly, and fit the forward face of the safety to the detent plunger for proper "feel" when moving on and off safe.

Finally, blend/contour the back edge of the shield to the frame to avoid any sharp edges/discomfort and to enhance appearance.

 

[entropy]

And it doesn't hurt to hold it down with the thumb while shooting.

 

[Jim K]

I installed a bunch of those ambi safeties with no problem. Unless that one is different, there is no spring connected to the right side thumbpiece; it is held in place by the right grip.

If the safety is going to the "off" position in firing, the problem is on the left side. If the safety spring and plunger are OK, it is the shape of the ambi safety itself that is the problem. Compare the left side of the ambi safety with the original safety; you can probably see the difference. Don't just start grinding things or drilling holes until you are sure what the problem is; those safeties are easy to ruin and pretty expensive to just start playing with.

Jim

 

[Rmeju]

Hi all!

You helped me ID the problem, and I was able to fix it!

The problem was indeed the geometry of the detent on the left side/right thumb side of the safety. The detent needed to be deeper. My safety is already mismatched and needs to be replaced, so I didn't mind monkeying around with it. I just wanted it to function. So I took a tiny ball shaped dremel bit and made it deeper, and smoothed out the "ramp" portion so that it didn't get stuck in the engaged position.

I just put 250 rounds through it, and there's no more problem!