Lyman GPR/Davis Triggers

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Joined
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Howdy folks. So I picked up a Lyman GPR and it works great. Double set triggers work. I decided to pickup a Davis deerslayer double set trigger, to spice her up a bit. Well now I’ve got issues, it dropped right in with no wood removal but now the lock won’t engage unless I set the rear trigger first. Then it goes to half cock, and full cock and fires like it should. It also doesn’t matter if I back out the set screw or tighten it up a bit. Seems there is a problem, Or am I dense and this is how they operate?
 
I have no experience with the Davis trigger but a lot of experience with double set triggers in general. If the Davis trigger has a set screw as this photo shows the rear trigger bar can be adjusted. This bar is at its highest when unset and will interfere with the sear. Take your trigger out of the rifle and adjust for the lowest rear trigger bar position that still has a good snap when set and released.
More like this.
IMG_0270 by Oliver Sudden, on Flickr
IMG_0271 by Oliver Sudden, on Flickr
 
I have no experience with the Davis trigger but a lot of experience with double set triggers in general. If the Davis trigger has a set screw as this photo shows the rear trigger bar can be adjusted. This bar is at its highest when unset and will interfere with the sear. Take your trigger out of the rifle and adjust for the lowest rear trigger bar position that still has a good snap when set and released.
More like this.
IMG_0270 by Oliver Sudden, on Flickr
IMG_0271 by Oliver Sudden, on Flickr
Unfortunately I don’t see this screw on the Davis Trigger. I see it on the stock GPR trigger.
 
Look at the driving spring that is pressing down on the set (rear) trigger lever. It should be possible to reduce the pressure on the rear lever that is lifting the lever causing the interference with the lock function. Loosen that spring by turning a screw in the trigger plate. With less tension on te rear trigger lever, it should be lowered enough for the set triggers to function as intended.
 
Here is something I have posted a number of times. Not your exact trigger (it’s a TC trigger in the photographs, but basic adjustment is the same as a Davis Deerslayer and Lyman/Investarm trigger), but if you follow along you should be ok. If process steps don’t resolve your issue, you may need to remove/add (shimming) some wood in the lock mortise of the stock, or removal of some metal from the trigger. Try the below steps first. Requires the removal of no wood or metal, both of which can be a PIA add back.

Hope this helps. Here is a description of how I adjust my TC and similar set triggers. Apologize that the photographs are not the greatest.

In the first photograph the arrow is pointing at the screw that will adjust the amount of tension on the rear trigger. You can back this screw off to reduce the amount of force to ‘set’ the trigger, but you still need enough tension or force to trip the sear lever on the lock. Once you have found the minimum force required (trial and error adjustment of the screw), tighten the screw a half to a full turn (safety margin). Confirm it is still satisfactory, and then you may want to lock it in place with something like nail polish (I use red so I can easily see it). Make sure the trigger is fully locked into place in the stock when testing its function. If it is lose or out of position it will perform different.
1655416622420.jpeg




To adjust the ‘hair’ trigger, with trigger assembly out of the gun, set the trigger and turn the screw between the triggers until the trigger pops. Then back off the screw a minimum of a half turn, though I would suggest a full turn for safety reasons. Lock in place with nail polish.
1655417142073.jpeg
 
Here is something I have posted a number of times. Not your exact trigger (it’s a TC trigger in the photographs, but basic adjustment is the same as a Davis Deerslayer and Lyman/Investarm trigger), but if you follow along you should be ok. If process steps don’t resolve your issue, you may need to remove/add (shimming) some wood in the lock mortise of the stock, or removal of some metal from the trigger. Try the below steps first. Requires the removal of no wood or metal, both of which can be a PIA add back.

Hope this helps. Here is a description of how I adjust my TC and similar set triggers. Apologize that the photographs are not the greatest.

In the first photograph the arrow is pointing at the screw that will adjust the amount of tension on the rear trigger. You can back this screw off to reduce the amount of force to ‘set’ the trigger, but you still need enough tension or force to trip the sear lever on the lock. Once you have found the minimum force required (trial and error adjustment of the screw), tighten the screw a half to a full turn (safety margin). Confirm it is still satisfactory, and then you may want to lock it in place with something like nail polish (I use red so I can easily see it). Make sure the trigger is fully locked into place in the stock when testing its function. If it is lose or out of position it will perform different.
1655416622420.jpeg




To adjust the ‘hair’ trigger, with trigger assembly out of the gun, set the trigger and turn the screw between the triggers until the trigger pops. Then back off the screw a minimum of a half turn, though I would suggest a full turn for safety reasons. Lock in place with nail polish.
1655417142073.jpeg
Thank you for this detailed response. Let me try this and I will report back. Thanks!
 
Here is something I have posted a number of times. Not your exact trigger (it’s a TC trigger in the photographs, but basic adjustment is the same as a Davis Deerslayer and Lyman/Investarm trigger), but if you follow along you should be ok. If process steps don’t resolve your issue, you may need to remove/add (shimming) some wood in the lock mortise of the stock, or removal of some metal from the trigger. Try the below steps first. Requires the removal of no wood or metal, both of which can be a PIA add back.

Hope this helps. Here is a description of how I adjust my TC and similar set triggers. Apologize that the photographs are not the greatest.

In the first photograph the arrow is pointing at the screw that will adjust the amount of tension on the rear trigger. You can back this screw off to reduce the amount of force to ‘set’ the trigger, but you still need enough tension or force to trip the sear lever on the lock. Once you have found the minimum force required (trial and error adjustment of the screw), tighten the screw a half to a full turn (safety margin). Confirm it is still satisfactory, and then you may want to lock it in place with something like nail polish (I use red so I can easily see it). Make sure the trigger is fully locked into place in the stock when testing its function. If it is lose or out of position it will perform different.
1655416622420.jpeg




To adjust the ‘hair’ trigger, with trigger assembly out of the gun, set the trigger and turn the screw between the triggers until the trigger pops. Then back off the screw a minimum of a half turn, though I would suggest a full turn for safety reasons. Lock in place with nail polish.
1655417142073.jpeg
Okay so it works. That back screw for adjustment is pretty darn loose. I see why you say lock it down with nail polish.

Now the issue is when I have it on full cock and go to set the trigger it goes off. So my assumption is the trigger is bumping the sear when it gets set and a slight file job on the trigger would solve that issue? Just a guess.
 
Welp. I think I found the issue. This screw head is contacting the stock, I need to do a bit of carving, or small drill. Instructions even say this may happen, sheesh. I overlooked this problem 🙄
 

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Now the issue is when I have it on full cock and go to set the trigger it goes off. So my assumption is the trigger is bumping the sear when it gets set and a slight file job on the trigger would solve that issue? Just a guess.
I would shim the trigger plate (increase the distance between the trigger and the sear bar) to see if that resolves your problem. If the shim works, you can decide whether or not to file the trigger, but I suggest making the shim permanent and leaving the trigger as is.
 
Welp. I think I found the issue. This screw head is contacting the stock, I need to do a bit of carving, or small drill. Instructions even say this may happen, sheesh. I overlooked this problem 🙄
Wood/metal interference in the wrong place can cause all sorts of problems, especially when installing a new component like a trigger. While you are checking things, make sure the trigger moves freely without interference and the sear bar on the lock is not making contact with the stock, checking it at all three positions (full cock, half cock and fired). I find that something that visually transfers any offending contact points is very helpful.
I prefer Prussian Blue, available at your local auto parts store, maybe $5 - $6. Likely in stock. Very little goes a long way and a tube will last a long time.
1622127648020.jpeg

Others use things like lipstick, ink marks from a Sharpie, chalk, lamp black….. many options.

If you find any interference, from the stock wood can easily be removed with a sharp chisel, knife or X-Acto for example. Just use something sharp and go slow.
 
Wood/metal interference in the wrong place can cause all sorts of problems, especially when installing a new component like a trigger. While you are checking things, make sure the trigger moves freely without interference and the sear bar on the lock is not making contact with the stock, checking it at all three positions (full cock, half cock and fired). I find that something that visually transfers any offending contact points is very helpful.
I prefer Prussian Blue, available at your local auto parts store, maybe $5 - $6. Likely in stock. Very little goes a long way and a tube will last a long time.
1622127648020.jpeg

Others use things like lipstick, ink marks from a Sharpie, chalk, lamp black….. many options.

If you find any interference, from the stock wood can easily be removed with a sharp chisel, knife or X-Acto for example. Just use something sharp and go slow.
Sounds good. Thank you so much. I’m going to check this later this afternoon and see what I come up with. I just happen to have a tube of Prussian blue so I’ll dab some on there and see what I come up with. Thanks again!
 
Wood/metal interference in the wrong place can cause all sorts of problems, especially when installing a new component like a trigger. While you are checking things, make sure the trigger moves freely without interference and the sear bar on the lock is not making contact with the stock, checking it at all three positions (full cock, half cock and fired). I find that something that visually transfers any offending contact points is very helpful.
I prefer Prussian Blue, available at your local auto parts store, maybe $5 - $6. Likely in stock. Very little goes a long way and a tube will last a long time.
1622127648020.jpeg

Others use things like lipstick, ink marks from a Sharpie, chalk, lamp black….. many options.

If you find any interference, from the stock wood can easily be removed with a sharp chisel, knife or X-Acto for example. Just use something sharp and go slow.
I learned with bright red lipstick and its cheap at the dollar store
 

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