Colt 70 series possible problem with hammer following slide

[1911Delta]

Picked up a used series 70 from a gun show a few weeks ago. It shoots like a dream, has only had one failure to extract , last round of the mag spent casing got caught up in extractor. My problem. Was cleaning it after my second outing to the range (have shot approx 150 rounds of blazer brass ball thru it). After cleaning, was doing function and safety checks. I had gabbed the gun. Had the grip safety fully depressed, then let the slide slam forward, no mag inserted. Well the hammer fell to the half cock position. Now this concerns me. I reaplaced the sear spring with a c&s I had and did the same test, hammer fell to half cock.
So I grabbed a mag, inserted a dummy round and tried to duplicate the problem. Couldn't. With a dummy round in mag, I could not duplicate the hammer falling to half cock.

Any insights? Advice?

 

[rcmodel]

Just marginal sear spring strength.

The loaded mag & stripping a round slows the slide enough to prevent hammer follow.

It doesn't do it when you are shooting because the trigger is too the rear when the shot breaks, and the disconnecter uncouples the sear from the trigger before you release it.

If you hold the trigger back and drop the slide on an empty chamber, the hammer should not follow, ever.

I would suggest you put just a tad more bend in the left leg of the sear spring.

That will put extra pressure on the trigger bow and keep it from bouncing off the sear/disconnecter with no round in the gun and the trigger foreword.

In the event that doesn't fix it, your hammer hooks or sear edge may already be dinged.

The cure for that is re-cutting them with stones & a sear jig, or replacement with new parts if they are too far gone to fix.

rcmodel

 

[1911Delta]

Doing as you suggest, holding the trigger back and letting the slide slam forward, the hammer did not follow the slide. I did this 5 times to make sure. I will put the bend forward on the left sear tang, and go back to shooting it to see if it will be suitable for carry. Thanks for the advice.

 

[1911Tuner]

The problem is caused by inertial trigger bounce. Basically, the trigger is standing still when the gun jerks forward and bumping the disconnect...which moves the sear just enough to clear the hooks, but not the half-cock.

The hammer may be bouncing a little, too...which makes it more apt to happen...but isn't normally the cause unless the mainspring is seriously in need of replacement.

Bending the left leg of the spring increases tension on the sear, but doesn't do anything to resist the trigger. Bend the center leg for that...and be careful to grasp the leg above the junction point or it'll snap off. Easy does it. A little dab'll do ya.

 

[rcmodel]

+1

Of course 1911tuner is right!

I had a brain-fark, (senior moment) when I typed that yesterday!

rcmodel

 

[1911Delta]

thanks 1911tuner. Did that. No more hammer following slide, unless I press down hard on the grip safety (not a normal firing grip). Still can't get it to follow with a dummy round or holding the trigger back while letting the slide slam forward.

Back to shooting it and getting it ready for carry.

Thanks all.

 

[1911Tuner]

Still can't get it to follow... holding the trigger back while letting the slide slam forward.

That's because it gets the disconnect out of the picture. The disconnect...connects...the trigger and the sear when it's in the fire position. When the slide rides over it, the disconnect is pushed down and into the disconnected position. By holding the trigger back, it can't reset and can't bump the sear.

No sweat, RC. I have'em all the time. These days...more and more, it seems.

 

[1911Delta]

Thanks again gentlemen. You 2 are a wealth of knowledge. Tuner, I it safe to continue to shoot and see if it's reliable for carry!

 

[stevemis]

No more hammer following slide, unless I press down hard on the grip safety (not a normal firing grip).

Isn't this cause for concern?

 

[Jim Watson]

Would be for me.

 

[1911Delta]

it's not for me. When , the only time the hammer followed the slide after the suggestions here were done, I had to push in the grip safety in an odd, not usual way. Picture this. Place your thumb on the bottom of the grip safety right where it meets the mainspring housing. Now your fingers are on the front strap. Looks like you are pinching it. So it is not a natural grip and the grip safety is pushed in further than when you normally hold the gun while firing.

I fired 50 rounds last night. Starting at 2 at a time to be cautious then full mags. Not one single problem. I won't carry it until let a smith look at it

 

[45auto]

That would be a problem for me!

 

[1911Delta]

Got back from smithy. He did what Tuner said about the middle leaf and put more bend/tension it than I had. Checked eveything, hammer, hooks, sear, disconnect. And gave it his blessing.

Again. Thank you all for the help.