not holding half cock

[FlinterNick]

All,
I have a TRS Tower Long land lock that is functioning fine in my hand..ie..holds half cock n...unable to get it to go off in HC. Nice transition to full cock. Buttery smooth. When I place it into the stock I will not hold half cock. Goes off just as if on full cock when I pull the trigger. What is going on? How can I correct this. Pictures are at half cock. I can send more pics if needed. This is frustrating as I tested in the stock earlier and it worked fine. At the end game now...can't believe this came up.

It could be a few issues.

Hard to tell without seeing the lock in action, my best guesses from the picture.

1. The sear nose may need to be chamfered and refit to the tumbler or the tumbler half cock notch could have a burr in it that wasn’t cleaned up.

2. If this is an older lock, the case hardened surface may have worn away, and the sear half cock interface seized up.

3. Sear Screw in the picture looks like it might be slightly off, if the screw isn’t shouldered To the plate correctly, it could cause the sear to seize up. The sear on the plate without the bridal or sear spring should swing pivot freely when the screw is tightened down, if not then the screw wasn’t shouldered correctly.

4. Lastly as some suggested above it could be a wood issue, that the lock mortise is hitting something and keeping the sear from fully engaging, this would be relevant if the lock falls off half only when in the stock.

5. Sear spring may be positioned incorrectly, from the pictures it seems ok.

PM me if you need additional help, I’m building a few of these now.

 

[bjarard]

Tried all of the above. I'm going to try a new sear..it does look like th.e tooth may have chipped slightly. Only thing left in my quiver. I did do a little deepening of the HC notch...seems to hold a little better...more pressure to set off....both with trigger. I'll report back finding once new sear is installed.

 

[ColonialRifleSmith]

Either your sear is hitting wood, or the trigger plate needs to be filed. I'd say send it to someone who actually knows what they're doing. Semper Fi.

 

[Comfortably_Numb]

If it works outside of the gun you don't need a new sear. If I had it in hand I could probably have it fixed in five minutes

 

[Commodore Swab]

As Mike said, possible causes can be inletting, engagement. As I mentioned earlier try without the trigger. Something else as a possibility with no wood interference the lock plate can sometimes be warped be screwing in too tight. Try loosening it a little to see if that helps. If so the same inletting may be a problem where the plate sits not where the seat rides.

 

[FlinterNick]

If it works outside of the gun you don't need a new sear. If I had it in hand I could probably have it fixed in five minutes

Yeap, if the lock works outside the stock is a wood issue. It it doesn’t, it could be a number things.

From the look of the picture i think it’s possible that the sear isn’t pivoting, screw looks like it’s not shouldered.

I would take the lock appart, and check the sear screw to see how straight it is, and also it’s possible that the bridle and sear and not in appropriate alignment.

If it works outside of the gun you don't need a new sear. If I had it in hand I could probably have it fixed in five minutes

 

[Dusty_Traveler]

It's hitting wood somewhere inside. Paint the bottom of the sear with some transfer media and work the hammer. It will be plain as day where to skim some off.

 

[Flintandsteel]

From the photos, there doesn’t seem to be a half cock notch. Either worn off, or broken off.

 

[Snooterpup]

If it works outside of the gun you don't need a new sear. If I had it in hand I could probably have it fixed in five minutes

Absolutely right. I’d add to remove the trigger and trigger guard. Install the lock.
Try to fire the lock by pushing on the sear with a flat blade screwdriver. If the lock works then there is an engagement problem with your trigger.
I does look like the trigger is slipping to the side of the sear. Possibly too much trigger wobble?
Best of luck! Let us know how it turns out. Possible over tightening the lock mounting screws may be tilting the lock causing the mis-alignment.
Snoot.

 

[FlinterNick]

Yeap, if the lock works outside the stock is a wood issue. It it doesn’t, it could be a number things.

From the look of the picture i think it’s possible that the sear isn’t pivoting, screw looks like it’s not shouldered.

I would take the lock appart, and check the sear screw to see how straight it is, and also it’s possible that the bridle and sear and not in appropriate alignment.

All,
I have a TRS Tower Long land lock that is functioning fine in my hand..ie..holds half cock n...unable to get it to go off in HC. Nice transition to full cock. Buttery smooth. When I place it into the stock I will not hold half cock. Goes off just as if on full cock when I pull the trigger. What is going on? How can I correct this. Pictures are at half cock. I can send more pics if needed. This is frustrating as I tested in the stock earlier and it worked fine. At the end game now...can't believe this came up.

Something I also noticed in the pictures.

The lock bolt is drilled too high, as it clears the top of the plate, this might be kicking the lock out of alignment when it’s bolted down into the stock.

 

[Comfortably_Numb]

YIKES!

 

[Snooterpup]

Something I also noticed in the pictures.

The lock bolt is drilled too high, as it clears the top of the plate, this might be the lock out of alignment when it’s bolted down into the stock.

Holy cow! I never even noticed that. How did that ever pass inspection?. Strip the lock, have a GOOD welder close that up.
Correctly re-drill and tap, angle screw hole in stock to match new correct hole.
I would bet nothing will ever be right until this is corrected. This MUST be corrected first. Failure to hold the lock properly against the barrel, especially at the top, will cause all sorts of woes. Deal with the trigger troubles then. Sorry to say but this has turned into a much larger project. Can be fixed but not quick or easily.
Best of luck
Snoot

 

[bjarard]

From the photos, there doesn’t seem to be a half cock notch. Either worn off, or broken off.

there's a hefty notch. its the sear tooth that could be an issue.

 

[bjarard]

Holy cow! I never even noticed that. How did that ever pass inspection?. Strip the lock, have a GOOD welder close that up.
Correctly re-drill and tap, angle screw hole in stock to match new correct hole.
I would bet nothing will ever be right until this is corrected. This MUST be corrected first. Failure to hold the lock properly against the barrel, especially at the top, will cause all sorts of woes. Deal with the trigger troubles then. Sorry to say but this has turned into a much larger project. Can be fixed but not quick or easily.
Best of luck
Snoot

yeah..I saw that...but its tight as a drum...no movement or slanting. ??

 

[Dusty_Traveler]

yeah..I saw that...but its tight as a drum...no movement or slanting. ??

Is your lock screw tight as a drum, too? It just need be a tiny bit over finger tight. A super tight lock bolt can wreak havoc on operation.

 

[TDM]

Something I also noticed in the pictures.

The lock bolt is drilled too high, as it clears the top of the plate, this might be kicking the lock out of alignment when it’s bolted down into the stock.

Wow, amazing that it's holding the lock at all. Not good at all.

 

[bjarard]

Is your lock screw tight as a drum, too? It just need be a tiny bit over finger tight. A super tight lock bolt can wreak havoc on operation.

No. Finger right then a couple turns of screwdriver

 

[waksupi]

No. Finger right then a couple turns of screwdriver

Finger tight plus maybe a half turn is plenty.

 

[Dusty_Traveler]

No. Finger right then a couple turns of screwdriver

I would consider this too tight.

 

[Dusty_Traveler]

I make sure the lock is fully seated in the stock, then I use only 1 finger and thumb to turn the driver. No wrist action at all. Turn it till it stops then go an addnl 1/8 of a turn.