Trigger Question on Mk 4

Most of the time the trigger is a solid 2 stage unit. Pull till the two lugs engage and then a crisp break and it goes the rest of the way. But once in a while it is a single stage unit. Maybe once out of 15 times?

I've the CD on this rifle and everything appears to be good. The two bumps on the trigger look new, the sear end is as shown in the book, engages well, and is crisp off the second stage, and the face of the engagement lug on the bolt looks good. The trigger guard and plate is flat but does have a very small, 1/32", downward movement when the main screw is turned in. It is a MK II bolt in it -

I've pulled the stock off it and assembled the rifle without it and every time I work the bolt and trigger it works flawlessly. I even moved the main screw up and down a bit to see if that was causing any issues and there aren't any that I can see.

I have noticed in some pictures the main screw has what appears to be a metal bushing it goes through prior to engaging the threads in the receiver.

Any ideas on this? It's one heck of a surprise when it goes single stage.

Thanks

Steve

Sorry - it's a No. 4 Mk 2 (least the bolt is stamped Mk II

It's not what the BOLT says, but what the body says. Come back when you can tell us what Mark/type of body the rifle has. But very basically, if it sa going from a perfect double pull-off to a single pull-off trigger occasionally, then something is moving slightly or an axis pin is worn.

But no one can answer the question until we know more

Here ya go - Attachment 31782Attachment 31783

Ah, it's a Mk1. Check that the fore-end is fitting properly and not moving back and forth. Make sure that the trigger guard is FLAT. Contrary to what some amateurs will tell you, the trigger guard is not, nor has it ever been used as a medium to adjust the trigger pull-off. Replace the sear and trigger axis pin as a matter of course..

Oil, assemble and test again.

If it is STILL giving you the occasional single pull-off go for the bolt and see that the striker is dead straight and that the cocking piece is tight on the striker.....................

I could go on and on but most of it is pretty obvious.

When you've reached the end of the line, go back and stone a little from the radius of the LOWER trigger bent. That'll give you a tad less first pull. But without the rifle on the bench, it's all conjecture

With thanks to Advisory Panel member Peter Laidler, check his article presented in two parts in the Technical Articles for Milsurp Collectors and Re-loaders (click here).

"The Trigger Pull-Off" - Part 1 (By Peter Laidler) (click here)

"The Trigger Pull-Off" - Part 2 (By Peter Laidler) (click here)


This interesting article is accompanied by a detailed photo montage of a previously damaged skeletonised No.4(T) rifle, used as a training piece for budding Armourers to learn with and develop their skills. As Peter says "It appeared that this ‘rifle’ had never been finished as a ‘T’ as the front pad hole had not been drilled. During bead blasting after a hard life as a skeletonised rifle, it was established that the screw had sheared off and simply been made off level. Drilled out and extracted, it’s back to its former self. Waste not, want not as they say…". Other photos in the article show the clear interaction of the sear, cocking piece and trigger during various phases of its operation.

Quote:

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Article Extract .....

Pictorially, this shows the trigger at the end of the first pull, both ribs touching the trigger bent or flat of the sear with the sear nose at the extreme edge of the cocking piece………, just ready for the off.

http://photos.imageevent.com/badgerd...s/DSCF0156.JPG
(Click PIC to Enlarge)

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Hope that helps … :)

Regards,
Doug

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Originally Posted by Norton1

I have noticed in some pictures the main screw has what appears to be a metal bushing it goes through prior to engaging the threads in the receiver.

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If it´s missing on yours, you should get one. Just hope you haven´t squashed the wood by overtightening the main screw.

Thanks all - and I did read both of those articles prior to posting.

And would anyone have the dimensions of the bushing? And I also hope I have not squashed the wood.

And what would be the best material to make the pins for the sear and trigger? Mr. Wadham's book talks about a tight trigger and what to watch for with that so I could put the unit in the milling machine and redrill them to accommodate a tighter trigger. By his measurements I am within tolerance on the trigger play.

Thanks
Steve

Replacing the axis pin should tighten it up as Peter said. Why redrill and go to a larger size? Seems extreme to me. I've got hundreds of bushings here if in need. You need a long one you can fit properly using Peter's article.

Brian - not to belabor the point but I have a small machine shop and I think I can make a bushing out of stainless, or any other material for that matter, rather than incur the expense of buying one. That's why I was asking for the measurements for it. Peter's article does not address the bushing per se but says "After ensuring that the collar is a PERFECT fit and is nipped between the body" which leaves me wondering how I would determine that fit. I can make the collar tight to the wood and the Main screw but how about length?

I'm a retired Marine Corporal. I don't have a lot of money so if I can manufacture what I need it saves me money and provides a lot of gratification in doing the job myself. Any assistance is very much appreciated and this forum has provided a ton of it!!

Thanks
Steve

Surely I tell how to determine the length of the bushing in the article. It's not a fixed length per se but a length that is suiteble for YOUR fore-end on YOUR rifle against YOUR trigger guard.

But to be honest, while you COULD machine one up from scratch, at what point do pennies become uneconomic? If you don't want to go to the expense of two original new trigger and sear axis pins, there's a cheaper way to go. Get ONE PIN, cap, fore-end and cut that into two lengths. One for the trigger axis and one for the sear axis pin. It is the exact diameter and that way, one long pin will get you two short pins.

... and while you´re at it, you could convert it to a Mk. II with the trigger hung from the action. Then you´d free yourself of all those problems that stem from bent trigger guards, etc. etc. influencing the trigger pull.

OK - I pulled the sear and trigger. Both pins are nice and firm. No movement on the sear pin and very little on the trigger pin. I believe the fit is quite nice. I checked the sear end where it interfaces with the striker knob and the sear was not as it should be. Again going off of the pictures and directions in the book on accurizing. So I got my Hard Arkansas stone out and began to work that over. As well as the striker knob portion which had some very fine lines in it. I now have that interface connecting quite squarely and the trigger feels crisp with a smoother primary pull than before. I also stoned the sear portion that engages with the bumps on the trigger as it had some very minor lines in it. This also helped smooth up the trigger with a distinct two stage trigger pull.

I'll re read your article Peter. As far as pennies? Anything ordered from here to any company would be a minimum of $10-$11 dollars just for the shipping. No matter how small the part. So as far as economics go it's cheaper for me to build it here.

I'm really not wanting to get into a scrap here. And it sounds like I am - so I'll take what I have and go forth. It'll shoot either way. Heck - maybe I've fixed it - and the sleeve I'll fabricate and then print your article out as re-assemble the rifle.

Villiers, good idea - but not likely for me to do it without some pretty detailed instructions. And hopefully I can repair it with what I've done so far.

Thank you all for the assistance -

Be well,
Steve

I measured a few for you from my bin and the long ones all seem to be .510 in length + or -. There may be longer ones. Most of the ones I have were fitted to rifles so they vary in length.

An excerpt from one of Peters old 'Jouster' posts in 2008 :

"......The COLLAR. You MUST have a collar and spring washer. This is what WE used to do. Put the front trigger guard screw into the trigger guard and body WITHOUT the washer or collar. Reverse it (that’s anti-clockwise …..) until you hear it click over the start thread and tighten it BUT COUNT THE TURNS UNTIL IT TIGHTENS AND LOCKS. Say, that it’s 7 ¼ turns to lock. Now do this with the collar fitted if it’s now, say 6 ½ turns, shorten the collar, a smidgin at a time, until the screw tightens up at exactly 7 ¼ turns. That way, you KNOW that the screw is tight, the fore-end is tight between the trigger guard and the screw and you are not crushing the living daylights out of the fore-end. And if it feels a little loose in a years time, then you can safely turn a few thou off the collar......"

Alan, that's what I did - made a nice collar out of stainless. Just need to measure the pressure and then see about how well it's shooting at 100 yards -

Thank you for the measurement Brian - gave me a starting point -

Be well,
Steve

All this talk about fixing the trigger has got me working on one of mine.

Every so often my No.4 Mk.1T would "single-stage" and so today I took a look at the trigger guard fixing. Sure enough with the front screw tight I got a single stage practically every time. Loosen it off and it goes back to the correct operation.

Now before I take it all to bits and do the counting the turns on the front trigger guard screw exercise, the symptoms look to me as though the bush is too short rather than too long. So finally to my question: if the bush is too long, it is OK to shim it out by the judicious use of washers?

I know that I should really fit a new bush and adjust it properly but, like our Marine friend, I'd like to save some time (procuring one) and money.

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Originally Posted by Beerhunter

if the bush is too long, it is OK to shim it out by the judicious use of washers?

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Of course I meant "too short" but this system won't let me edit my original post.

OK - I made a bushing and after working it down I ended up at .476 length on it. Nice tight fit and sets into the recess very nicely. I honed all of the surfaces, except the trigger bumps, to a nice finish and checked for alignment with Blue ****m. It's all nice and square.

I did everything I could to get it to go single stage and it is a lovely double stage trigger. 3 lbs of pressure on the first stage and 4lb 11 oz on stage two. And it is really crisp! I'd like stage two to be a bit lighter but will shoot it this way first and see what it does. Up pressure on the barrel is a tidy 4lbs and change. I happen to have a trigger gauge and used it to measure the weights.

So a question or two yet:

1) Is the up pressure only allowed on the last couple of inches of the wood?

2) How would I lighten the trigger pull a bit more? Most of my rifles have 3 1/2 lbs of trigger pull on them.

And I went slow - took me a while to get everything smooth and shiny and then parallel with each other.

Be well,

Steve

Your trigger pressures MUST fall into these categories. 1st pull between 3 to 4 lbs. 2nd pull, between 5 to 6.5 lbs. They are the specification laid down.

The last 2" or so of the fore-end has the barrel bearing surface so it's this area that the barrel bears down on.

To Terry (Beerhunter) - I picked up a new bushing for you from Phil Rose today, it will need to be trimmed to length but won't be too short... I'll bring it to Bisley Sat or Wed - are you shooting? No charge for the part.
Rob

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Originally Posted by RobD

To Terry (Beerhunter) - I picked up a new bushing for you from Phil Rose today, it will need to be trimmed to length but won't be too short... I'll bring it to Bisley Sat or Wed - are you shooting? No charge for the part.
Rob

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That is so kind of you Rob. I shall be at S/S on Wednesday.

Of course that means I can't put off doing the job properly as per Peter's instructions.