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Old 11-27-2015, 03:56 PM   #1
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Join Date: Nov 2015
Location: Pennsylvania
Posts: 3
Problem with grip safety

Okay, I'm not a gun smith, just a guy that has worked on all types of guns in the past 45 years.
A friend hands me a AMT 1911 M/P Express. Even at a distance you can see it has a lot of miles on it! Says he had it to two gun smiths work on it and they can't figure out why the grip safety isn't working. He asked if I would look at it.
Upon disassembly I found the small "finger" on the grip safety that goes against the disconnector was broken off! Easy fix right? I replaced the grip safety. All other internal parts seemed to be okay with just showing some wear. Upon reassembly, the grip safety still didn't work. I then replaced the sear spring thinking there wasn't enough tension on the sear. That helped but dry firing and racking the slide, the grip safety now only works about 60 to 70% of the time. The trigger weighs almost five pounds now. It has an extended target type trigger with a lot of lateral play but it's bow looks to be near 100% of its original shape. It does have a over travel screw but I have it backed out just enough so there is just a bit of over travel.
At this point I'm stumped. Any suggestions will be greatly appreciated!

Thanks in advance.

Dave
 
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Old 11-27-2015, 05:02 PM   #2
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Join Date: Jun 2001
Posts: 1,680
You're not clear on what the problem is:
Is the grip safety blocking the trigger even when it's depressed, or is the grip safety not blocking the trigger at all?

The 1911 grip safety doesn't work on the sear or the disconnecter, it works by contacting and blocking the trigger bow and prevents the trigger from moving back.
The only effect the sear spring has on the grip safety is to push it out to re-engage it.
If the sear spring were to be completely removed the only effect it would have is to allow the grip safety to disengage and stay disengaged.

The actual operation of the grip safety is really pretty simple.
The lug on the grip safety contacts the right-rear of the trigger bow and blocks it.
When the grip safety is pushed in, this pivots the safety lug upward and allows the trigger to slide under the grip safety by-pass.

First, make sure the new grip safety is not a Series 80 safety that has the thinner safety lug.
The Series 80 grip safety requires a thinner lug to clear the Series 80 firing pin safety activation levers in the right side of the trigger group.
The older, original grip safety has a thicker lug.
Even the Series 80 safety should work on the older models but this could be an issue in a non-Colt frame.

Next, disassemble the frame, removing everything except the trigger itself.
Remove the grips.
Replace the grip safety and hold it in place with a section of drill rod.
Replace the mainspring housing and install the housing retaining pin.
By looking through the hole in the frame were the thumb safety seats and up through the magazine well you can see the operation of the grip safety as it pivots in and out.

Look for:
A Series 80 thin safety lug allowing the trigger bow to by-pass the safety lug.

Look for the fit of the bottom of the grip safety and the top of the main spring housing not allowing the grip safety to move freely or to move out fully.
Often new grip safeties or new main spring housings don't fit together well, especially on non-Colt frames.
Too tight a fit may cause the grip safety to stick, or may block it from moving out all the way.

Look for a mis-fit of the grip safety lug to the trigger bow.
Again, some replacement parts on non-Colt frames may prevent the grip safety properly contacting the trigger bow and can either fail to disengage or fail to engage correctly.
Some will disengage if the grip safety is allowed to move out and the trigger is pulled. The trigger pull can force the safety to disengage by pushing the mis-fitting lug up.
Others may fail to disengage if the trigger is released before the grip safety is allowed to move out. In this case the grip safety stays in, held by the trigger bow.
These are usually caused by the end of the grip safety lug being mis-shaped.
You usually see this on cheap, substandard parts.

Try totally removing the trigger stop. Even if you have over-travel, remove it completely. This will totally remove it as any possible factor.
If you have a standard trigger handy, drop it in and see what happens.
Do the same with another grip safety if possible.

The fact that the trigger pull suddenly increased indicates the grip safety lug is not fitted correctly and is pressing on the trigger bow even when it should be totally clear of the trigger.
Look for WHY the lug is contacting the bow.
Is it mis-fitted or mal-formed?
Is the grip safety not pivoting in far enough for the lug to clear the trigger bow?

This can be aggravating because the shape of the working part of the safety lug doesn't look at all complicated.
Mis-fitted or mal-formed just a little and all sorts of bad things happen, such as the grip safety not disengaging, or pushing the safety out of the way if the trigger is pulled and the safety is engaged.

For more info and good pictures and discription of how to fit the grip safety, buy a copy of the Jerry Kuhnhausen Shop Manual Volume One on the Colt .45 Automatic pistols from Brownell's. This is THE manual on 1911 repairs and replacement parts.

Last, these problems are made worse by out of spec frames as made by too many of the older 1911 makers like Vega, Crown City, and AMT.
It's tough to find and diagnose the actual problem when the frame is already not made correctly.

To be operating correctly the following HAS to be happening:

1. If the safety is engaged (not depressed) the trigger may move slightly to the rear BUT...the sear should not move AT ALL.

2. If the safety is depressed the trigger should move freely to the rear without contacting the lug by-pass area.

3. If the safety is depressed and the trigger is released, the safety MUST pop back out. when pressure is taken off it.

4. If the safety is not depressed, pulling the trigger must NOT push the safety off or allow the sear to move.

Here's your best buy if you need to work on a 1911:

http://www.brownells.com/gunsmith-to...prod13805.aspx

Last, this might help. It's a set of production blue prints used by US government 1911 pistol and parts makers.
It shows the exact dimensions of the grip safety lug:

http://brlcad.org/design/drafting/M1911-A1_REDUX.pdf

Last edited by dfariswheel; 11-27-2015 at 05:24 PM.
 
Old 11-27-2015, 07:46 PM   #3
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Join Date: Nov 2015
Location: Pennsylvania
Posts: 3
Thank you Sir for your reply!

It is a series 70 grip safety. Okay I did exactly as you said and I can see the operation very clearly now. It appears that the rear of the trigger bow needs to be about .030 to .040" higher on it's left hand side. Looking at this part of the bow when it is out of the frame, it is either worn away or some one ground it down trying to polish it. It is dished out more in the center and lowered across it's entire width.

As it is now, with the grip safety released and hammer back, pressure applied to the trigger, the hammer will fall but other times the hammer will not fall. There isn't enough contact with the grip safety and the triggers bow to allow the pistol to function reliably and safely.

The grip safety and the main spring housing seem to be working correctly together. Meaning the safety is not binding anywhere around the frame. The two legs on the grip safety that lock it into the main spring housing are only about .050" thick. I believe if I would file or stone them thinner, wouldn't make much difference to the contacting surfaces. However, I could be wrong because I only need a little more contact with the triggers bow.

I have an account with Brownells and will be purchasing a copy of Jerry Kuhnhausen's book on my next order.

Thanks again.

Dave
 
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