2011 Hammer Drop Problem

[MedicAJ]

So, I exchanged grips on my SPS Pantera with an STI, and now when pulling the trigger the hammer will not drop about 50% of the time. I can pull the trigger completely to the rear, but the hammer remains cocked and will not fall. After about 5-6 trigger pulls, the hammer will finally fall. 

 

I've torn the pistol down and reassembled several times now, ensuring that the sear/disconnector/leaf spring orientation are correct, as well as dialing out the over travel screw all the way, and returning the pre travel tab to the neutral position. Any other ideas? Thanks!

 

Andy

[Powder Finger]

take out the mag catch and see what happens.

it it works then the trigger itself is stopping rear movement.

[MedicAJ]

17 hours ago, Powder Finger said:

take out the mag catch and see what happens.

it it works then the trigger itself is stopping rear movement.

Tried it without the mag catch, same problem.

Swapped triggers and it's still happening.

I'm befuddled.

 

[Jmo2011]

Check to see if the rear of the trigger bow is contacting the frame and limiting travel. 

[MedicAJ]

The trigger has uninterrupted movement until the bow contacts the rear of the frame here. 

[Powder Finger]

try putting the hammer/sear/disco in but only push the main spring housing up enough to get some sear spring pressure

push the hammer forward with your fingers and see if it releases (only use the housing for sear pressure not hammer pressure)

I assume the frame is the same just new handle, so I'm thinking the main spring housing may be blocking the trigger

if the above works the main spring housing must be oriented different in the new grip.

[38super]

Disconnector is not rising up to engage the trigger stirrup

[Absocold]

Assemble the gun without the grip safety installed. This will let you see what's going on inside there and tell what's going wrong.

[hlpressley]

So, I'm experiencing the same thing after swapping to the same grip on the same gun. My hammer will fall, but only half way. Any recommendations?  

[Absocold]

First/easiest thing to check is if you're getting enough trigger pull distance to fully disengage the sear. Make sure the trigger overtravel screw is all the way out. Make sure the front of the trigger bow isn't hitting the magazine by duplicating the issue with magazine removed.

 

Second thing to try is to bend the middle sear spring leaf in a bit to give the disconnector more spring tension to make sure it's moving fully upwards and fully engaging the sear legs. Also check the disconnector channel that goes up through the frame to make sure there's no dirt/grit/burrs that are changing the disconnector angle. Polish sear spring contact area on disconnector.

 

And once again, the gun will work normally if you assemble it without the grip safety. This gives you a window into the gun to see what the problem is with the trigger/sear/disconnector interface.

 

Once you've solved the issue, do a full function and safety check to make sure nothing else got borked up. Especially make sure you don't have hammer follow.

[38super]

Medic, my apologies.  The disconnector shovel needs to contact the sear legs.  Insufficient trigger travel will allow the sear to disengage from the hammer hooks but not rotate the sear far enough to clear the half cock notch.  This beats up the sear face causing trigger probs down the road. 

[38super]

Does your trigger have a take up adjuster?

[BeerBaron]

If you mean the pre-travel adjustment all sti triggers have it. The issue here is more likely over travel (not enough). 

[kalaikanui]

I just recently tried to put an STI grip on my Pantera and had the same results as other mentioned here. Very long story short... after many parts mix and match trials, the tolerances inside the SPS grip are different than the STI's and the orientation of the groove at the bottom of the grip for the sear spring is different allowing the sear spring to move inside the STI grip to the point that it finds its way under the disconnector after a shot or two. It didin't matter which combo of high end parts I used; I kept getting the same result. I ended up putting the OE SPS grip back on with the high end fire controls and trigger in it and it worked just great. The entire exercise was motivated by wanting an ICE magwell in the first place, so now I'm just moding the SPS grip to accept that. Hopes that saves others the time and frustration