inconsistent trigger pull

[ralfie]

Newbie here. Would like to know why my new norinco 1911a1 (350 rounds thru it so far) exhibits varying trigger pulls. There are times when trigger breaks crisply/cleanly and times when i can feel "creep" - the hammer would move very slightly forward before it completely falls on the firing pin. Is this just normal? What can be done to remove the "creep"? Thanks in advance!

[Hawkmoon]

Roughness on the tip of the sear and/or the hammer hooks can do that.

Go here http://www.m1911.org/full_technic.htm then scroll down about 1/3 of the way in the list of articles. Read the one called "Poor man's trigger job."

[mike h. buness]

I'll add here that many parts can cause the "creep". #1 to check is the sear/hammer. The trigger stirrup and slot are also suspect. An overlooked area is the dissconecter, MIM dissconectors can be a problem. Try trigger pull without a clip and compare with mag in. Let us know how this goes.Mike.

[1911Tuner]

Creep is caused by one or several things. The most common being over-length hammer hooks, or only one hook bearing on the sear, etc. The trigger varying from crisp and clean to long and creepy suggests that the sear isn't resetting into the hammer consistently. This could be due to the sear spring being incorrectly tensioned...magazine or top round in the mag contacting the lower corner of the disconnect...Disconnect not resetting consistently...sear spring again...insufficient side clearance of the sear due to roughness or sizing...or any combination of the above.

Varying trigger pull from inconsistent sear or disconnect reset is a concern because it's only a matter of time before it resets just to the very tips of the hooks...which sets up a very light and ticklish trigger...or leads to burst-fire/full auto if it jars off as the slide hits battery.

[SargeMO]

Usually the first thing I do to de-creep triggers is to fit good quality full-dimension hammer and sear pins, that are a snug fit in the frame; then I'll add a quality 'match' disconnector. This is often enough, but then and only then do I consider swapping sears or fiddling with hammer notches. To my thinking you have to take all the slop out that can affect hammer/sear engagement, before you can even evaluate it from the shooter's perspective.

[ralfie]

Thanks again for all your replies. I appreciate them all.
Just for add'l info, my trigger pull observations were made during dry-firing, without any magazine in the pistol.
I sure hope the gun doesn't go full auto on me anytime soon! Thanks for the warning 1911Tuner.
Before posting this thread I had the nork sent to a gunshop for "upgrades". It will be back later this week. Related to this trigger issue, I had the trigger, hammer and sear replaced with better (and more expensive) parts. I'm keeping my fingers crossed that the problem disappears when I get my gun back. If it doesn't, I'll check on the sear spring, pins and disconnector next time. More things to put on the shopping list...

[ralfie]

Got my 1911 back already! The trigger pull inconsistency was gone already.
I tried all the tests listed in the technical section of this site and everything was ok, except that the gun failed the half-cock test. The hammer dropped from half-cock position when I pulled the trigger. The gunshop manager said the gun was still "safe to use" and just needed "some easy adjustments" and they worked on it for a while again. When they gave the pistol back it seemed to be ok already. However, upon further testing at home I discovered that the gun would still drop the hammer from half-cock if the trigger was pulled with greater force. Everything works fine except for this issue. Does this have something to do with my original problem with the pistol?

[Hawkmoon]

It's not related to the original problem. It can't be -- you replaced the parts that caused the grittiness and creep.

I wonder if the new hammer they installed is a Series 70 style hammer with the captive notch, or a Series 80 style without the notch. If they put in a Series 80 hammer, pulling the trigger will allow the hammer to fall from half cock because it's designed to do that. But a Series 80 hammer should only be used in a pistol with a firing pin safety.

I suggest that you take it back to the gunsmith and tell him (not ask him) to fix it. It is unsafe, and you should make it very clear to him that you KNOW it is not functioning correctly since he worked on it, and if anything happens his name will be on the top of the list of people sued.

[ralfie]

I wonder if the new hammer they installed is a Series 70 style hammer with the captive notch, or a Series 80 style without the notch. If they put in a Series 80 hammer, pulling the trigger will allow the hammer to fall from half cock because it's designed to do that. But a Series 80 hammer should only be used in a pistol with a firing pin safety.

Here's a picture of the hammer used.

http://i68.photobucket.com/albums/i13/ralf0918/ebhammer897.jpg
It's an Ed Brown barstock Hardcore hammer.
I was wondering if a weak sear spring could be causing the sear to not catch the hammer's captive notch adequately. 1911Tuner wrote:"The trigger varying from crisp and clean to long and creepy suggests that the sear isn't resetting into the hammer consistently. This could be due to the sear spring being incorrectly tensioned...magazine or top round in the mag contacting the lower corner of the disconnect...Disconnect not resetting consistently...sear spring again...insufficient side clearance of the sear due to roughness or sizing...or any combination of the above."

[John]

An Ed Brown Hardcore hammer should NOT allow the hammer to fall from the half-cock notch, period. If it does, it means the sear is not going into the notch. Try putting some more pressure on the left prongue of the sear spring. If that does not fix it, as Hawkmoon says, take the pistol back to the gunsmith and demand to fix it.

[Hawkmoon]

That's the correct hammer. Look at the 3:00 o'clock position in your photo -- that's the half cock notch. You can see that there are tiny legs extending downward to capture the tip of the sear. What you need to verify is that the tip of the sear is actually going into that notch and resting behind those legs. If it is properly seated in there, the ONLY way you could make the hammer drop would be to break off the legs.

I have a Chip McCormick hammer on which the notch is so narrow that a standard GI sear won't go into the notch. So it is possible that your hammer and sear aren't properly fitted. (In fact, since it doesn't work right, they obviously aren't properly fitted.)