• The WEAPONSIGHT, IMAGE INTENSIFIED, L1 series - 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.

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    Part 1
    By Captain Mainwaring
    (a.k.a. Peter Laidler)

    While this little bit of kit doesn’t strictly come under the LEE ENFIELD umbrella, some of you will immediately recognize it as being the night sight for the trusty old L42 sniper rifle ……, that definitely DOES come under the Lee Enfield umbrella.

    Yes, that’s the one….., recognize it from the photographs now? It is to THIS that the little ‘J’ shaped bracket in the left side of your L42 chest screws on to. And thus screwed to the rifle, turns it into a deadly nocturnal killer.

    This isn’t going to be a technical article, but more informative and helpful. But briefly, this sight has only just been declared obsolete in the UK Military and fully withdrawn from the system. So, now’s your chance to look for and find one. They were VERY popular through the late 70’s, 80’s and 90’s until ‘07 or so and thousands were sold commercially to foreign forces under the commercial designation of SS-20 as well as to our own as the I.I.W. L1 series (for Image Intensified Weaponsight). Manufactured by Rank Industries from Loughton in Essex, later called Rank Pullin, later GEC systems and latterly taken over by BAe Land systems. They’re called a typical first generation night vision scope but really, they were almost a second generation night sight for the simple reason that the actual zeroing was achieved by moving an internal glass etched plate reticle. And it’s this that made them VERY expensive because you have to a) make the plate moveable within the sight itself and b) the adjusters have to be both water/moisture and dust proof. Incidentally, it’s a reticle if it’s etched onto a glass plate.

    The earlier types had a fixed internal reticle and were zeroed by moving the whole sight up/down, left/right on the bracket in much the same way as the current SUSAT sight. But unlike the SUSAT, the night sights so mounted were was quite clumsy and their ability to remain zeroed was at best, marginal ….., but I digress. Back to the old L1

    There were 7 basic variants but the differences were …….. look, if you want the truth, I have all the minutiae but unless I study it all in great detail, I haven’t got a clue. But, I’ll break it down into what we needed to know as Armourers and Instrument Techs!

    The earliest ones had a plain, flat, knurled battery cover (part number Z7/5855-99-962-9170) while the later versions had a CONTROL, Brightness (Z7/5855-99-965-3962) battery cover with a rotating knob on the end. This was the Automatic Brightness Control (the ABC) version. This allowed the user to adjust the brightness of the reticle to suit the ambient light. To go with and allow for this, the inverter, the bit inside the inverter housing, (it’s under the cover, just in front of the battery housing and held down with two 6BA screws) has been changed from INVERTER, Power, Static (X2/6130-99-117-8700) to INVERTER, dummy (Z7/5855-99-966-1130). That’s because the power isn’t now static, it’s adjustable …., got that!

    Now, there was/is also three different variants of reticle. The first is what we call the INFANTRY pattern and this is the type that is used on all of the infantry weapons that would accommodate the sight, including the L1A1 rifle, the Carl Gustav anti tank gun, the AR-15/M16, the GPMG and the L4A9 Bren. This reticle pattern is shown under Note #3 by "harlikwin", under the Collectors Comments and Feedback section below. This reticle pattern is a little X above three vertical lines. The middle line has three identical vertical lines to the left and right. There's nothing else!

    The next two were what we called the ARTILLERY pattern and were used when the sight was mounted on the 105mm pack gun in the anti-tank role or dare I say it, in the anti-personnel ‘canister’ role. From this, you’ll understand that this sight was a big, bold and beefy bit of kit! These reticles are easy to identify as they have the letters L and R above the vertical upright stadia lines to indicate to the Artillery lads the direction of left and right….only they’re the wrong way round! There were two variations of this sight. The first, now obsolete variant didn’t cater for tanks at different ranges. The secont pattern was marked 2 to 800 yards. You’ll quickly see that this type took a bit of the guess work out of the range of the tank or oncoming personnel.

    The modification from L1 to L7 spec could easily be achieved in Base Workshops by upgrading or modification of the ABC and Inverter or replacing the reticle pattern. From this, you’ll soon see that regardless of what yours has on the identification plate, if it has the flat screw-on battery cover and the infantry reticle pattern, then it is an L1A1 sight. If it has the ABC battery cap/cover and an infantry reticle, then it is an upgraded L1A1 so it is an L1A7.

    As for the remainder, from the L1A2 through to the L1A6, then briefly:

    A2 Flat battery cap, first type Artillery reticle pattern
    A3 Haven’t got a clue (HGAC) but think it was a hand held unit
    A4 Flat battery cap, second (2 – 800 yards range) pattern reticle
    A5 HGAC but presume ABC battery cap and first Artillery ret pattern
    A6 HGAC but presume ABC and second type Artillery ret pattern

    You can just imagine it now…….. the actual CASE, weaponsight Image Intensified was a minefield because as the sight fitted into it exactly, it followed that as the sight was modified from a flat battery cover to an ABC type, the case changed. As it did when it became an Infantry variant and required the different weapon mounts! But to keep it simple, I’ll explain what the CES consisted of:

    ADAPTOR that screwed to the actual sight that slides and locks to any of the following ..... MOUNT, L1A1 for the GPMG. MOUNT L2A1 for the Carl Gustav. MOUNT L3Ex1 (very rare, never seen one!) for the AR15/M16 and MOUNT L4Ex1 for the L1A1 rifle

    FILTER, Cap. Spare for the front OG lens

    CONTROL, Brightness. A spare ABC battery cover

    HOLDALL. The padded holdall bag. Fits into the lid of the box


    EYEPIECE Assy. A spare ocular lens assembly. Cost about £850 so NEVER, never, ever left in the box under any circumstances. Always kept in the Instrument shop.

    BRUSH, dusting, lens. A lens dusting brush

    TISSUE, lens cleaning. Otherwise they’d use scotchbrite

    The User Handbook ‘Image Intensifier L1A1’

    Infantry Training Book, ‘Image Intensifiers’

    Last but not least, the CASE. Image Intensifier

    Ah, yes, colours! I have only ever seen them in the two standard Army colours of Black and Kakhi Green but I dare say that Rank would supply them in any colour the buyer requested. But kakhi and black seem to be the most obvious

    If there’s any feedback from this totally boring and useless article, next time I’ll do a short piece about how you can look after yours and what to look out for if you’re on the hunt for one. In the meantime, the useful little booklets that form part of the CES are available as reprints, very cheaply from Brian Dick at BDL Ltd. (click here), in South Carolina, USA.

    The two different brackets that bolt to the underside of the sight. On the left is the standard or universal bracket. While that on the right is the little ‘J’ shaped bracket found in the L42 rifle chest. Above it is a new one, still sealed in its Ordnance issue bag.

    (Click PIC to Enlarge)

    Note this part number well. B1/1005-99-964-3254 and if you see one, grab it FAST. They are as rare as rocking horse droppings.

    (Click PIC to Enlarge)

    The sight with its additional brackets (less the rare AR15/M16…) and spare batteries as fitted snugly into the bottom half of the case.

    (Click PIC to Enlarge)

    The contents of the top half of the case with the holdall pulled out, showing the lens brush, tissues and handbooks stored below the holdall.

    (Click PIC to Enlarge)

    Pictorial view of an L1A7 night sight. You know it is a late version by the ABC type battery cover.

    (Click PIC to Enlarge)

    The two little handbooks. The blue training guide and the buff user handbook. Both available in reprint format from Brian Dick at BDL Ltd. (click here), in South Carolina, USA.

    (Click PIC to Enlarge)

    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)

    2. Here are a set of pics showing the PVS-1 night scope mounted on my L42A1. Note the picture of the batteries that came with it and specifically the date on them. It's 1993 and they still work. I had to throw a couple out that were dated back in the 70's. I hope I can find replacements in the future. Also Notice that they are 7.0v instead of 6.5v. While the batteries shown in the picture are marked 7 volts, a 6.5 volt battery is identical. This is because each individual cell in the battery produces 2.12 volts. These particular batteries are 3 cell units, therefore 3 x 2.12 = 6.36, if the units in question were four cell units they would be '8 volt' (actually 8.48 volt). The 7 volt nomenclature is unlikely to be correct, although a six volt battery fresh off the production line will show 7.xx volts. More important for anyone who owns such a device is the amp hour rating of the battery, as this will have a greater effect on the run time of the device. Please note that it's highly illegal to throw them in the garbage or dispose of them anywhere but a hazardous waste facility. ...... (Feedback and pics provided courtesy of "Ricoim")

    (Click PIC to Enlarge)(Click PIC to Enlarge)

    (Click PIC to Enlarge)(Click PIC to Enlarge)

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    3. The IWS weapon sight was a 3.75x magnification first generation British weapon sight, based on a triple staged intensifier tube with Automatic brightness control, in fact it is the same tube that was used in the later versions of the US PVS-2 system. It was designed to be mounted on the L42a1 rifle, Carl Gustav rocket launcher, L1a1 rifle, and M16 rifle and the L7 GMPG.

    It was powered by two 6.75 volt mercury batteries providing about 70-100 hours of power for the unit. It is superior to the PVS-2 type system in that it has an internally adjustable reticle (graticule) that lies in the front focal plane of the weapon each click is ½ Mil of adjustment (1mil =~3.4 MOA). In contrast the PVS-2 had a fixed reticle and could only be used with externally adjustable mounts designed for specific weapons such as the M16 or M14. The effective range for the unit is 300m under starlight conditions, improving to 500m in higher ambient light conditions (moonlight) which is similar to ranges for the PVS-2 unit of the same vintage. During the Vietnam war PVS-2 equipped XM-21 sniper rifles regularly scored kills out to 300-500m. The sight comes equipped with a front lens cap that incorporates a neutral density filter to be used during daylight to zero the unit, it can be set to three settings.

    The reticle of the unit:

    Points a and b on the reticule correspond to 200m and 500m respectively for 7.62mm weapons. The cross above point a is used to boresight the Carl Gustav anti-tank weapon. Points b,c,d,e,f correspond to 100, 200, 300, 400, 500m when using the Carl Gustav Lines G,H,I correspond to leads of 7.5 mils, 15 mils, and 30 mils respectively. These were typically employed when using the Carl Gustav, but could also be employed as windage holds with the 7.62mm rifles.

    Zeroing the Unit:

    Place unit in stable rest and sight the rifle at 200m using iron sights. While viewing the target through the eyepiece adjust the filter and focusing knob to obtain a clear image. Adjust the reticle screws so that point a on the reticle corresponds to the target. If possible verify the zero by firing a group. Adjust if necessary.
    ...... (Feedback by "harlikwin")

    IWS Reticle

    (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 WEAPONSIGHT, IMAGE INTENSIFIED, L1 series - Part 1 (by Peter Laidler) started by Badger View original post
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