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brown dog

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  1. Not my list, but made me smile: Rolex = Mercedes Omega = Bmw Patek = Rolls Royce Lange = Ferrari Richard Mille = Porsche Grand Seiko = Lexus Seiko = Toyota Breitling = Range Rover Oris = Volvo Audemars Piguet=Bentley JLC = Aston Martin Tudor= Nissan Vacheron = Aston Martin Cartier= Jaguar Tag Heuer = Ford JlCoultre= Cadillac Rado=Suzuki Breguet =Audi (Think I'd amend Rolex to: 5 digit, and earlier, Rolex = Mercedes 6 digit Rolex = stretch Hummer.)
  2. NSNs are pretty misunderstood. Even bins, brooms, pencil sharpeners and bog roll have NSNs. A lot of gun and tacticool marketeers use that to imply that the product has passed some sort of test.. but no, it just means that theyve applied to have the thing catalogued. And NSNs are irrelevant to the way SF (and booties aren't SF, they're infantry, albeit specialist amphibious infantry, just as paras aren't SF, they're infantry with a parachuting specialism, but, once delivered, both paras and marined just do 'normal infantry', not SF stuff) purchase what they need. They just, more or less, purchase what they want at a unit-ish level. This chap will probably have been presented with an SF unit-level 'buy what we want' smorgasbord to choose from.
  3. brown dog

    Scope elevation question

    Some fag packet maths: At 6 degC, mv reduced to approx 2686fps Speed of sound at 6 deg C 1099fps So if the air pressure was 1000mb, your rounds were firmly subsonic at approx 1100m. If the pressure was 1100mb, they were subsonic at 1000m. (I'm sitting typing this at 1043mb) Depending on how long before 1000m your bullets experienced transonic disturbance , or if the temp dipped further, or the pressure crept up a bit, or your ammo was a smidge slower you're definitely in the parish for seeing a transonic effect on the target at 1000m. ...and that, depending on bullet and conditions can make everything 'fine' at shorter range, and then suddenly, as you reach further out on a cold day, the wheels suddenly fall off for no obviously apparent reason...... Once you're aware of this sort of stuff, there's no need to tear kit apart or doubt inputs when bullets go 'odd' way out there on a cold day, it's just a matter of recognising the physical limits of the game when/if you bump up against them😊😊
  4. brown dog

    Scope elevation question

    Thanks ☺ Need to know the temp that was fired at etc
  5. brown dog

    Scope elevation question

    A 4 click change at 800 is well within tolerance - a 15degC temp change to inputs and a small pressure change would easily, and sensibly, cause that. What bullet are you using? And weight? What mv (and recorded at what temp)? Zeroed at precisely what distance? And at what temp and pressure? Smack on, or off a bit? What were the temp and pressure on the 'wheels fell off at 1000m' day?
  6. brown dog

    Scope elevation question

    Yup; not experienced 'zeroing on the 2nd turn'. - I can see that accounting for the 'can't zero before elevation reaching end-stops' problem - good spot Roy! - but I'm not clear how it subsequently accounts for 'zero achieved and all fine to 800, then wheels fall off'. Presumably, the zero issue was addressed successfully prior to the long range session (or else, how was it shot?) Two separate issues?
  7. brown dog

    Scope elevation question

    Pops, yes, I agree, probably the simple cause. If you want to increase your ballistic nerditry ( 😊 ) Increased humidity decreases air density. Counter intuitive, but it does. 'Cold' per se, will not be the primary determinant of air density - station pressure will. Eg -20 on top of Everest vs -20 in Resolute Bay. The effect to which I'm referring is the randomness, or disruption, caused when bullets transition from supersonic to subsonic flight. In terms of projectile flight, the effect is a 'randomizer' - up, down, anywhere, and will be accompanied by a deterioration in group size. The primary determinant for the speed of sound is temp. Pressure is, for practical purposes irrelevant to determining the speed of sound. I'd wager that today, with a temp induced mv drop, as well as a temp induced reduced speed of sound, the bullets were transitioning after 800m but before 1000m. - and, if 'finger trouble' of any sort can be ruled out, decreased range to transition may well be, given the cold snap, an effect not often considered or seen - but very real and noticeable when it happens
  8. brown dog

    Scope elevation question

    I'd be inclined to agree, most of these odd outcomes have simple, rather than complex causes. My money is almost always on inconsistent position and hold from occasion to occasion. That said, as in my post above, it was cold today. No idea what round was in use, but if it's a pedestrian 308, transition will have been occurring not far 'after 800m'....and that can cause the wheels to fall off beyond that distance in a number of ways.
  9. brown dog

    Scope elevation question

    The error occurred at 1000, the 'step distance' from the previous range (800) doesn't determine the angular error, the new range does - so only 3.6 off expected POI. Cold today....A problem beyond 800m. Hmm: RAW, at what range do your programs tell you your bullets were transitioning to subsonic flight at today's temp? (Edit to add: For a bit more precision, also reduce your input mv by 3fps for every degree colder it was today, compared to when you chrono'd your load)
  10. Pops, Have a read of this old thread. I think your answer's in there
  11. brown dog

    Ammo from 1960s compared to today.

    Well, when you're legislating for the lowest common denominator - idiots who can't shoot accurately, but are happy to brass up a sentient mammal with unpredictable, probably suboptimal, bullet placement- then undoubtedly, from an animal welfare perspective: Yes. Put simply, bigger bullets have more 'kill'.

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