• The Trigger Pull-Off - Part 1 (by Peter Laidler)

    The following article is published with the kind permission of Advisory Panel Member, Mr. Peter Laidler. On behalf of MILSURPS.COM members, we'd like to publicly thank him for his support of this forum, as well the broader Lee Enfield collector community in general.

    Note: After you click on images to ENLARGE them, you may find they automatically size smaller in your browser's window making them hard to read. The auto sizing is your browser's way of keeping images entirely within the screen size you have set. If this happens, you will see a small box in the bottom right hand corner of the pic with four arrows point outwards. Click this box and the pic will EXPAND and open up to its normal size, so you should now be able to read any text and make out small details.

    "The Trigger Pull-Off"
    Part 1
    By Peter Laidler

    I hope that by now you’ve all got on your workbench and almost fully assembled No1 or No4 or 5 rifle. Assembled and almost complete except for the trigger pull offs. Now, you’ll see the importance of starting the job with a perfectly assembled bolt. The FIRST thing I want to emphasise is that if the cocking piece on your bolt is loose on the striker….., in any way, or wobbles up and down or left and right, then read no further because whatever happens, you’ll never get a consistent pull off. But what you CAN do is strip it down, degrease it and if my memory serves me correctly, then clean the ¼” BSF threads ……ah, it makes me breath a sigh of relief to hear those old imperial thread sizes again…. In the cocking piece and striker and do one of two things.

    The EMER states that if they are loose, then you can stamp a small letter ‘S’ on the striker thread to tighten it up in the cocking piece. I’d prefer it if you would flux it and run a coating of soft solder around the threads. That never fails and I don’t call that a bodge either. Having got the striker tight in the cocking piece, we’re ready to go. The second test is to draw the assembled bolt back and forth in the body and make sure that the nose of the cocking piece fully clears the short/underside locking lug of the bolt. If it does, then we’re ready to go.

    But first, here’s a few points I’d like to make clear. The top of the sear that contacts the cocking piece is the NOSE and this must be undamaged, beautifully smooth and round. The flat that the trigger ribs bear on is the trigger bent. This must be absolutely flat and polished in an up and down manner. NOT across! I know this might sound a bit long winded but believe me, when you’ve done it a few thousand times, it becomes second nature, believe me …….., especially when you have beady eyed examiners like David Lines, Mr Amto and Mr Saw out-inspecting your work prior to range testing. Oh yes, where were we? Yes ….., the trigger has two raised humps on it. These are the ribs. The BOTTOM one, closest to the axis pin or finger part is the FIRST rib or bent. All this rib does is act on the trigger bent of the sear, drawing the sear smooooothly down the face of the cocking piece until the topmost rib contacts the trigger bent of the sear. This TOP trigger rib or bent is called the second or the PULL-OFF rib.

    Then, just as the second or pull-off rib of the trigger contacts the trigger bent of the sear, several things happen. Firstly the rotatory angle of attack between the trigger and the sear changes slightly increasing the leverage required by your finger to squeeze (or rotate) the trigger any further. Now the trigger pressure increases from the FIRST pull of between 3 and 4 pounds pressure to the second pull off pressure of between 5 and 6.5 pounds pressure. And at the same time, the first pull has lowered the nose of the sear to within a gnats knacker of the very bottom edge of the face of the cocking piece. Now, you just need to gently squeeeeeeeze the trigger that last smidgin, exhale, cross-hair level, pointer upright, add that extra pound and a half of pressure and off it goes.

    Now DO NOT MOVE, observe the target, follow the flight of the bullet through the haze. The observer will be doing the same through his binoculars……… Good hit, now release the trigger and wait. But wait ….., just how do we get to the point of perfection with the trigger pull off……………. That’s coming next.

    Are you sitting comfortably-, then we’ll begin. (apologies to all those post war 50’s era kids who remember this phrase from the BBC ‘listen with mother’ programmes!)

    NOTE: This skeletonised rifle is in fact a previously damaged No4T. 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…

    (Click PIC to Enlarge)
    The action of the No4 Mk1 at rest. Note that the top, pull-off rib is resting on the sear. This is because the sear is depressed, held down by the fire-off cocking piece. The No1, 4 and 5 all use the same action.

    (Click PIC to Enlarge)

    The action cocked. Now, the BOTTOM, first pull rib is acting against the sear. Squeeze the trigger now and as the trigger rotates rotates under a weight of between 3 and 4 pounds, it’ll rotate the sear downwards, sliding it smoothly down the face of the sear until the upper rib of the trigger comes into contact with it. Then it’ll pause while the top rib takes over…………………

    (Click PIC to Enlarge)
    …..there you go, from the left side. The top rib has contacted the trigger bent of the sear. Now, all that is required is a slightly heavier pull – to between 5 and 6.6 pounds – watch the target, crosswire level, pointer upright and square on, slightly exhale………, then the last squeeze and the job is done.

    (Click PIC to Enlarge)
    Rifle cocked, but trigger released. Notice the sear nose half-way up the face of the cocking bent of the cocking piece.

    (Click PIC to Enlarge)
    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.

    (Click PIC to Enlarge)
    FIRED. Sear clear of the cocking piece, cocking piece forward, top trigger rib now touching the trigger bent or flat of the sear. The rifle is at rest. This is ‘THE FIRED POSITION’

    (Click PIC to Enlarge)
    As in PIC above, the trigger mechanism at rest

    (Click PIC to Enlarge)
    Armourers shops had a large amount of triggers in a box that they’d use in order to get the best, and often, perfect fit before resorting to stoning, I did hear that you could bend the sear nose to effect the perfect pull-off. Don’t bother lads, they’re hard and will snap if you try.

    Copyright ©2006 - 2009 by Peter Laidler and MILSURPS.COM

    Collector's Comments and Feedback:

    1. In addition to being a trained and highly experienced military "Armourer", Peter Laidler has authored two excellent books about the No.4(T) sniper rifles and their No.32 scopes. They are titled "An Armourer's Perspective: .303 No.4(T) Sniper Rifle", which he co-authored with Ian Skennerton and his own dedicated work, "Telescope Sighting No.32".

    If you're really interested in some in-depth learning about the No.4(T) sniper rifles and the No.32 series of scopes, their history, evolution, repair and adjustments for shooting, I'd highly recommend those two books, which are pictured below.
    ....... (Feedback by "Badger")

    (Click PIC to Enlarge)

    Note: The opinions expressed herein or statements made in this article are solely those of the author, and do not necessarily reflect the views of the Military Surplus Collectors Forums, or the ownership and moderation group of this site. MILSURPS.COM accepts no legal liability or responsibility for any claims made or opinions expressed herein. Also, please note that neither the author nor MILSURPS.COM recommends that any member of these forums, or a reader of this article, try this type of experimentation without the proper knowledge, equipment and training.
    This article was originally published in forum thread: "The Trigger Pull-Off" - Part 1 (by Peter Laidler) started by Badger View original post
The SMLE 1903-1989