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Zak Smith

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Posts posted by Zak Smith

  1. B.C. affects the degree of deceleration of an object. It largely depends on weight of the bullet. The term means [mass] divided by [diameter squared] divided by [a constant based on the object's shape]. Increasing weight improves B.C. Improving B.C. reduces deceleration. Less deceleration means more velocity downrange. More velocity means less drop.

    The thesis that "You need to use a heavier bullet than the normal 165 grain variety [to make it to 1000 yards]" is false.

    Mass is not the operative parameter.

    BC is an average ratio of Cds swept over the mach range of "this bullet" and the base G1 projectile (for G1 BCs which are the ones we see everywhere).

    If all bullets had the same "shape" the thesis would be true within a given caliber. The bullet shapes are emphatically not the same, so it doesn't. This explains why a 155 Scenar (which is longer than a 175 SMK) can have a higher BC than a 168 SMK.

    A ballistic calculator only needs an accurate BC, the MV, and environmental conditions to accurately model the trajectory.

    -z

  2. 308 at 1000 yards or more. You need to use a heavier bullet than the normal 165 grain variety,

    Total BS. The operative parameter is the B.C.

    But to answer the question---

    No need to make this real complicated.

    308 will make it to 1000 yards no problem, with a little care in bullet selection. I shoot the 155 Scenars to 1000 yards almost weekly.

    Every long-range shooter should have a 308 bolt gun. I say this because the crux of shooting LR is wind estimation and similar basic skills. 308 enables much more practice due to its low ammunition cost (bought or reloaded) and long barrel life. Even if he has a magnum caliber, 308 will enable volume practice that the cost of the magnum caliber would not permit.

    Calibers which are expensive, non-standard, or involve inordinate reloading effort should be avoided for a first "long range" rifle and only subsequently considered for relatively low-volume applications. Recommending an Ackley for a first long-range caliber is insane. Even a 300WM, which has decent factory LR match ammunition available, will be over 2x the cost of shooting 308, not counting the shortened barrel life. With Lapua brass available for 308, and many solid and tested reloading recipes, there is little that can go wrong, and little load development time needed.

    Even going with a LR or magnum cartridge like 260, 7RM, or 338LM, the shooter still has to account for wind (as others have said). A exemplary 1000-yard cartridge like 7RM (shooting a 168gr VLD @ 2950), still has 60% of 308's wind drift at 1000 yards. So you can't ignore wind.. just get a little more margin of error.

    For logistical reasons, most people will practice LR shooting out to 500 to 800 yards. 308 is certainly sufficient for these distances. After a year of shooting, if he feels like he needs a better LR caliber, get a second rifle in a caliber with FAR better ballistics, like some of the 6.5, 7mm, or 338 choices listed here. The 308 remains the high volume gun for bulk practice, and the new rifle is for low-volume practice beyond the capability of 308. This keeps costs (ammo and barrel) and time (reloading effort) under control.

    If you need to hit things beyond 1500 yards, I can attest 338 Lapua is a good choice--

    A100_2061_img_cc.jpg

  3. The device you want is technically possible, but when you combine everything together, the economies of scale diminish and the price would be very high.

    For example, PDAs are cheap for their computing power and flexibility because they sell a gazillion of them to geeks and business people.

    The cost of a good rifle scope starts at about $1000 and the really good ones IMO are about $2k.

    The cost of a good laser rangefinder starts at about $600.

    The cost of anything with custom circuit boards and firmware in this kind of volume is going to be pretty expensive ($500 at least).

    I know most people just tape a bullet drop chart on the gun stock and try to guestimate it from there.
    There is no reason to guess anything but the wind value.
  4. Probably a bad idea with anything other than a rifle length gas system.

    There are multiple different lightened carriers out there. The lower the mass, the more finicky the system will become.

    I am currently running the Y/M lightened carrier from MSTN and it has almost the reliability of a full weight carrier.

  5. 7mm-08 kind of lacks the case capacity to take full advantage of the high-BC 7mm bullets, but it shouldn't be worse than 308. 260 Rem is a better choice for MOR.

  6. Nothing sweeter than an STI/SVI running, but they don't work out of the box.

    It looks like you are saying a factory STI or SV gun will not run out of the box.

    Funny...

  7. Yep, it's for 3Gun/tac/sniper junk where there's no PF and I don't want a real heavy or long gun. It can double as a house gun, or even carry... kind of why I went with the fixed sights.

    A 6" down the road would be a good reason to buy ANOTHER gun!!!

  8. The AI brake has a metric thread and requires a sleeve region turned to "about" 0.83" behind the threads. The standard 308 brake is moderately effective and not very loud. It is less effective than the JP BC comp, but the JP is much louder for both shooter and spotters.

    The new AI two-chamber brake uses the same muzzle pattern, but is much larger and is much more effective on large gas volume cartridges (e.g. 300 & 338). I have tried it on my 308 and noticed some difference.

    A suppressor on 308 class cartridges reduces the recoil and report to 22LR, but does increase OAL and weight.

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