Enfield foresight adjustment

Discussion in 'Shooting, Hunting and Fishing' started by Blogg, May 8, 2009.

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  1. Sure I could work this out but cannot be arrsed.

    How much movement of the foresight produces a lateral point of impact shift of 1 minute for a:


  2. No.4: 0.008" per inch off the top of my head. No.1 will be something around the order of half that.
  3. ugly

    ugly LE Moderator

    I have a table which is stuck to the inside of my range book, when I get home and if I am sober I will look it up!
    Mind you the fore sights both require a cramp device and in the No1 it needs the nose cap removing to adjust the foresight!
    I have one each for the No1 and the No3 rifles and I no longer use them, Ex_Stab has first call on them!
  4. Kind of you, I have one for the No.4 ........

    For any firearm with iron sights the formula is easily calculated as follows:

    (Correction at Target X Sight Radius)/Range = Correction on Sights.

    Unit must all be common, eg, if you uses inches for hte sight radius then the range must be in inches.

    For a No.4
    Correction @ Target =1"
    Sight Radius = 28 1/2"
    Range = 100yds = 3600"

    Correction on sights = (1x28.5)/3600

    Correction on sights = 0.007916667"

    Which if we round it up is 0.008 or 8 thousandths of an inch.

    In metric:
    Correction @ Target =25mm
    Sight Radius = 28 1/2" = 724mm
    Range = 100m = 100,000mm

    Correction on sights = (25x724)/100,000

    Correction on sights = 0.181mm

    Which might reasonably be rounded up to 0.2mm

    It wouldn't be hard to come up with a formula to give results in MoA or Mils but there's not really a lot of point as far as I can see, you can work out your correction on target easily enough separetely and in practice, for zeroing, you'll just measure on the target.

    Hope this helps.
  5. Ugly, if he has the earlier/later clamp-type foresight block with the number 4 he doesn't need the funny business of the adjustment tool, just a dial caliper and a home-made tool to loosen the clamp.

    I've even done it on a plain foresight block with a hammer and a drift before, but that is a real fag and takes ages to get right.
  6. Its not worth buying (expensive: £50-70 on eBay) No1 and No4 adjustment tools, if you only have a couple of rifles. A small hammer & punch is fine to make most adjustments. The later screw-clamp No4 foresight block is very weak, so its easy to drift the blade without slackening the screw.

    One standard foresight blade width equals 2" at 25 yds, or 7-8" at 100yds.
  7. ugly

    ugly LE Moderator

    Maybe I should flog mine on flea bay then?
  8. Thanks all.

    The No.4 in question has just the simple block and should be easy enough to do.
  9. ugly

    ugly LE Moderator

    What I have is some notes from an old club sec gleaned from his old manuals;
  10. No1 and No4 both have sights calibrated to be zeroed with bayonet fitted up to 300 yds, and then true range increments over 300 without the bayonet fitted.

    All rifle/bayonet combinations are unique, but broadly speaking, a No1 bayonet throws the shots about 18" high at 200 (and up to 6" L or R, depending which way the blade hangs), whilst a No4 spike throws them about 6" low.