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Adjusting Trigger Pull Weight

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britrifles View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: April 30 2018 at 2:39pm
Originally posted by Zed Zed wrote:

Yes the angle is 6° on the Fulton's No4; and I used this measurement for my No1MkIII* to use in Modified Service Rifle competitions. However the original L39A1 has an angle of 10°. At least that is what I read some time ago. I'll have to measure that to check when I get time.
What is essential for safety is that when you pull 1st stage of the trigger; the cocking piece will be pushed slightly rearward. So if you decide not to shoot and release the pressure on the trigger, the cocking piece must return to it's original position! If not it could cause an accidental discharge
 
Zed, the cocking piece on my Fulton No. 4 does get pushed back against the striker spring as the first stage is taken up and the movement can be seen (very slight).  I think it has to in order to return the trigger to the slack position when the trigger is released.  I've not been able to get the trigger to hang up in any way even when released from the near break point on the second stage.  But, what I do see, is the cocking piece getting pulled down slightly by the sear during the first stage.  The striker is pushed back slightly, and cocking piece rotates down at the bent which seems to be because it is slightly loose in the threads of the striker. 
 
I've got a few spare cocking pieces and when I get the bolt apart on my Fulton No. 4, I'll see if I can measure the angles of the bent face and take a close up pic.
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Shamu Quote  Post ReplyReply Direct Link To This Post Posted: April 30 2018 at 3:52pm
There's also the question of sear engagement. There was a tool & a technique that basically drove a wedge into the receiver rear to raise the amount of sear engagement with the cocking piece bent.
Let me see if I can find an illustration.
The tool, dimensioned in case somebody wants to fabricate one!

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Post Options Post Options   Thanks (0) Thanks(0)   Quote englishman_ca Quote  Post ReplyReply Direct Link To This Post Posted: April 30 2018 at 4:07pm
That tool actually decreases the amount of engagement of the sear on the bent as it will push the metal on which the sear sits at rest, downwards, and move the sear tip downwards towards the edge of the bent on the cocking piece.

Typically this tool is used when the sear sits too high in the receiver channel and catches on the the lower locking lug when cycling the bolt.

The tool is nice because it aligns itself with the edge and stakes the metal in exactly the right spot. I use a favourite sized center punch to reach in to put two dot stake marks on that land of metal close to the edge, which has the same effect as the tool.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Shamu Quote  Post ReplyReply Direct Link To This Post Posted: April 30 2018 at 4:14pm
Yes, I agree. The point was that you need to set it up to be fully engaged (even with a tad of movement from the safety) but not excessively so.

First pressure slides the upper sear bent, to just fully engage the cocking piece bent. The movement from here to "release", should be darn near instant. You should feel this in the trigger, first pressure is moving, second is only releasing. It should also fully reset to "first Pressure" position if you engage & then release the manual safety.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote englishman_ca Quote  Post ReplyReply Direct Link To This Post Posted: April 30 2018 at 4:40pm
I am lucky in as much as that I was around in the days of lots of surplus and cheap sporter Lee Enfields, I played around with the triggers and sears in an attempt to 'improve' trigger pull and let off.

What I did learn is that it does not take much stoning, filing, staking to make a big change to the workings of the trigger group. I destroyed lots of sears and triggers, ruined lots of cocking pieces.

The main parts are castings. I learnt that a sear tip cannot be bent without it breaking. The cup on a MLE trigger cannot  be tightened by closing up with a hammer. Changing the angle of the bent can also make it trip into half cock. In other words, I learnt how to bugger up  most of the parts in a trigger group without really trying.

I did learn a lot from the practice though. I now approach any trigger job very slowly and diligently. Too, too easy to screw things up royally. 
If I can find nice crisp factory original parts to use, I am usually happy with the pull off after just a little polishing. It is a balance between pull off weight and functionality.
With a used cocking piece, if I see any stoning marks on it at all, I will pass and find another.

The only exception to that which comes to mind is that of a very early cocking piece for a Mk.I MLM that I found. A very rare part. It had been stoned and wrecked. I had the tip hard welded and then I filed and polished back to spec. It was a lot of work. I heat treated it to harden and temper.

I know that many of the cocking pieces that I see for up sale on fleapay have been reworked and will only be grief and disappointment to their new owners. Buyer beware, usually no returns on these ones!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Canuck Quote  Post ReplyReply Direct Link To This Post Posted: April 30 2018 at 5:15pm
Glad I hoarded these said parts still in the original unopened boxes. Got lots of fun ahead trigger pull wise.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Zed Quote  Post ReplyReply Direct Link To This Post Posted: May 01 2018 at 3:40am


Here's a photo of my homemade stoning rig. There is a screw in the support under the lower end of the cocking piece that can be screwed in or out to adjust the angle of attack. Then polish on the Arkansas stone with oil.

Here's a photo of the Fulton's cocking piece being measured.
I totally agree with the comments by englishman; when stoning the face, take it very slowly.
I would add that if modifying the angle from 4° to 6° for example. Check how far up the face the sear contacts. You don't need to change the angle all the way to the top, as long as you've covered the area of contact plus a bit extra. Therefore saving some material that may otherwise be removed. 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: May 01 2018 at 8:18am
Clever rig, I like it.
 
The striker removal tool I ordered came in yesterday and I disassembled the bolt.  The cocking piece sear face needs some work; the surface is somewhat rounded.  The trigger pull measures 5 lbs right now, but would like to get it down to 4. 
 
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Shamu Quote  Post ReplyReply Direct Link To This Post Posted: May 01 2018 at 9:03am
That sounds like someone already "adjusted it"!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote englishman_ca Quote  Post ReplyReply Direct Link To This Post Posted: May 01 2018 at 9:04am
Trigger work is an art and a science. Lots of official information published in manuals to guide one through it. Once the concept of the two stage trigger is grasped, one realises just how clever the designers were at Enfield. 
If I took specs to a design office today and told them that I wanted two distinct stages in a trigger with two pull weights using a single spring, which will also do double duty as the mag catch return, they would look at me funny.

The design is brilliant in economy of design, robust with so few moving parts. It is sensitive to set up, but when set up well, that two stage trigger is sweet!

You might find that stoning the cocking piece bent face flat again to get the rounded bit out might remove metal enough to change the height of the bent edge slightly, due to the taper falling away behind it. If the edge where the sear trips gets too far rearwards, the slope of the half cock notch relief will come into effect, the sear might catch on the half cock notch and jump into half cock when gently squeezing the trigger. This is because now the sear when it trips is not low enough to clear the half cock notch and slams into it.
If this happens, it will be a losing battle, toss the cocking piece and start again with another or take it over to the welder.

I have seen many, many cocking pieces with file marks around the half cock notch trying to form a taper or ramp to let the sear tip slide past. Bubba thinks that he knows how to 'improve' trigger pull better than the factory. Goes at it gusto with Dremmel and file.

And yes, I wish that I too had little unopened boxes of cocking pieces, sears and triggers too. These days I am working with used parts a lot more. To me, sometimes it is just not worth the hassle of trying to rework somebody else's attempts. I always try to find untouched trigger group parts.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Zed Quote  Post ReplyReply Direct Link To This Post Posted: May 01 2018 at 11:47am
The trigger set up on the No8 training rifle is also very interesting to set up. Definitely worth reading the manual before touching anything. It is a very good system with a lot of adjustment possibilities.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote britrifles Quote  Post ReplyReply Direct Link To This Post Posted: May 01 2018 at 7:11pm
OK, made some progress, and will probably not do any more now on the trigger. Here’s what I did tonight:

1. Trued up the cocking piece bent face with diamond files, setting up in a vice such that the surface of the bent face was just slightly above the jaws of the vice at one end of the vice.   Using the front edge if the file as a guide along the vise jaws, light pressure on the file, worked the surface flat with medium grit, then fine, then X-Fine. X-Fine gives a near polished surface.

2. Cleaned and applied solder to the threads of the striker, wiped off excess with rag while still hot, this gave a nice thin coating of solder.

3. Greased the striker and spring, assembled. The solder on the striker threads really snugged up the cocking piece on the striker.

4. Assembled and pull tested. No movement of the cocking piece on the striker at all (there had been about 0.015 inches of downward movement during first stage of trigger pull).

5. First stage is now about 2.5 lbs.   Second stage is 3.5 lbs, right at the minimum limit for Vintage Military Rifle Rules. It was difficult to measure this because the second stage was letting off immediately when the first stage moved to the end of the travel from not being able to control the spring scale. But the trigger feels exceptionally good now, a very smooth first stage that will return the sear to the cocked position when the trigger is released, slight striker movement aft as the first stage is pulled up. Zero creep in second stage. The movement of the cocking piece on the striker (before I applied the solder) was causing a bit of creep in the second stage since the cocking piece was sitting slightly lower relative to the sear than it now is.

I’m not going to mess with this anymore, I don’t want it to get any lighter than this. I’ll get some range time with it to make sure it stays stable, then recheck pull. If it gets any lower, I will need to reset the angle of the cocking piece bent face.



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Post Options Post Options   Thanks (0) Thanks(0)   Quote Shamu Quote  Post ReplyReply Direct Link To This Post Posted: May 02 2018 at 6:00am
Sounds good to me.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Zed Quote  Post ReplyReply Direct Link To This Post Posted: May 02 2018 at 12:23pm
Sound's like you've got it working nicely. 
I use a spring scale too; but to be honest, I think there ok for comparing before and after; but not really accurate due to the spring action as the trigger lets go. A proper weight as used at competition scrutineering is the only really accurate method. I suppose one day I should make a proper one!
Also I've found that after reassembly with a well lubricated system, the let off can measure a bit lower until it's settled in after a few shots.
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