doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Boxlock Part Question

I have a relatively new Ugartechea boxlock, which I have posted about previously. (Long story short, it took three trips to LCS's gunsmith to get the safety working properly, but since then I have happily shot a few hundred rounds through it.) On my latest foray to the clays field I noticed that the screw that sits under the lever started to loosen up. Unfortunately I cannot name the screw, but it is locate din the same place as part number 38 on this Matador schematic.

First, can anyone tell me the name of this screw and its function?

Second, is there any danger of overtightening it? I noticed when it came back from the gunsmith at LCS that the screw slot was not perfectly aligned vertically. It may have loosened on one of its trips to LCS, or it may not be perfectly clocked. (Could the LCS gunsmith have ruined the alignment?) At any rate, I tightened it and would like to tighten it enough to line it up properly, but I do not want to overtighten it.

As you can tell, I am still new to the double gun world so your sage advice is greatly appreciated.

Name: loose screw
Function: driving you crazy

The Brits call it a hand pin or something. If it won't align fore-n-aft in about a 1/32 part of a turn, don't align it. Put some blue Loctite on the end of the thread and run it up snug. It's under the lever; fuggedabowdit.

jack

Top tang screw...probably called other things to other people but that's a common term. Go ahead and tighten it as it should be firmly tight as not to loosen up when the gun is fired. It usually screws into the trigger plate (into the lug that the triggers pivot on) and is a primary securing force of the action to the wood in a boxlock. That lug on the trigger plate usually has a slanted surface on it's forward face that this screw will pull upwards against the stock wood in a properly inletted stock and force the action and stock to seat firmly together. You can see that in the Matador schematic. In an improperly bedded stock, sometimes tightening the screw to the necessary point it needs to be will actually bow the unsupported triggerplate upwards and jam the triggers or the safety or both. Thats why sometimes you find them backed out a bit to allow the gun to operate OK, but it will lead to stock battering problems in short order. Wether it will line up properly when tightened properly is another story. Get it tight first.

It should be aligned longways with the barrel and flush with the top tang. It screws into the trigger plate. I would add some loctite as Jack said but I would line it up fore and aft.

Thanks. I will give it a shot tonight. Hopefully it will line up properly, but when I tightened it a bit last night it settled around the 1 o'clock- 7 o'clock position, which does not give me great hope that it will end up algined with the barrels.

It sounds as through it has been over tightened. I might be inclined to glass bed the top tang to re-establish the proper spacing between the tangs.
Steve

I want emphasize the importance of getting the tension on this screw just right. If it's too loose the stock will be loose and become battered and probably split. Too tight, and the relationship of the triggers to the sears and the safety's proper function is messed up. If it's really overtightened, it can cause the trigger blades to bear on the sears so tightly that the sear noses are partially pulled out of the hammer notches and the gun can discharge without warning.
The screw slot should have been indexed properly when it was assembled so that is your indicator of proper position. These screws are put in quite tightly originally so be sure you are not a full turn too loose. If it goes past proper aligment more than just a little bit, and won't stay tight, it should be rebedded as another poster mentioned.
This is all a long way of saying if you really don't know how to do this job, take it to a good gunsmith.

I tried it again and with just a bit more force, but not too much - still gently, it went almost a half turn more and lined up perfectly. Adding a little bit more after that didn't move it any further, so I think I got it exactly where it should be.

I appreciate all the help. Since I am still new to this, and since this is the most expensive shotgun I own (even though it is a cheapy by most SXS standards), I just needed a little courage and to know I wasn't going to totally mess something up. You guys have made my day.