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About BlueBoy69

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  • Birthday 09/13/1969

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    Target shooting, computers, films, documentaries, games, reading and women.

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  1. BlueBoy69

    303 cast bullets

    I'm a little confused alpha1, what Brinell hardness number (BHN) are you defining as 'hard cast'? Lyman No2 is pretty hard, around 16 BHN, though not as hard as the type metal alloys, such as monotype (23-29 BHN), linotype (19-23 BHN), etc.. Also, you state "you want an alloy that will fill the groves hard cast is not the way to go". The ability of an alloy to fill the grooves is down to the difference between the outer diameter of the projectile and that of the grooves diameter, along with the pressure applied to the projectile's rear. The latter pressure will elasticity deform the projectile if below its yield strength, and plastically deform it if above this level. As far as I'm aware you generally pick correctly sized bullet that is cast from an alloy the is suitable for the pressure the load you are using will be applying. You don't just say, don't use 'X' alloy, you say use 'X' alloy suited to your loading pressure. Sizing of the bullet is down to a multitude of parameters that have already been stated by Andrew. The most important of these I'm aware of are as follows: the firearm's chamber dimensions, more specifically the throat and lead; the barrel's bore and groove dimensions; for revolvers, the throat dimensions of it's cylinder.
  2. BlueBoy69

    Which RS powder for 6x47 Lapua?

    Yes QuickLOAD computes the useable case capacity based on the inputted COAL and projectile rear profile. QuickLOAD has a multitude of parameters, but it is still missing a multitude of factors and is essentially just a model. As you undoubtedly know, the accuracy of its predictions are only as good as the inputted data (user and integral), and ultimately, the model itself. It should always be treated as a guide, and not as fact. Neil
  3. BlueBoy69

    Which RS powder for 6x47 Lapua?

    Even using the shorter COAL, I take it you have tweaked some of the other settings somewhere, such as a smaller case capacity (46.65 grains of H2O) to get that pressure? Whatever the case, even at the standard of volume of 47 grains, it's still rather high (59,689 PSI) at your COAL and 39.8 grains of RS60. Looking at the computed data, RS70 seems a better bet for a mildly (11% NG) double base propellant, that or go with RS62 if you want single base. Reloader 26 gives the best MV vs pressure, but that's also a double base propellant. Neil
  4. BlueBoy69

    Which RS powder for 6x47 Lapua?

    No problem. I've not read it fully myself as it's quite a tome. Anyway here's data for 105 gr Scenars. I don't known which version you have, the slightly longer GB478 or the slightly shorter GB542, so here's one for each. Both are at max COAL. The length difference is so small that it doesn't really change the list all that much to be honest. 6×47 - 105 gr Scenar (GB478) - Max COAL .txt 6×47 - 105 gr Scenar (GB542) - Max COAL .txt
  5. BlueBoy69

    Which RS powder for 6x47 Lapua?

    You should be able to use the same powders as the 6 XC. Though both operate at roughly the same max pressure, you'd need to use slightly lower charges as the 6×47 has a slightly smaller capacity case. See attached QuickLOAD computed suitable powders file for other options. 6×47.txt
  6. BlueBoy69

    casting / swaging airgun slugs

    I had a look for some bullets I might have cast, but couldn't find any. I haven't used it in 20-30 years, so it's not surprising. As to what they look like, a pointed spitzer with a short amount of bearing surface at the rear and a slight waist at the very rear. The base has a slight conical hollow.
  7. BlueBoy69

    casting / swaging airgun slugs

    You mean one of these... albeit a .20 version.
  8. BlueBoy69

    N150, I’ve been told

    Be very careful, as many of the grain (kernel) sizes are quite similar. See image. Also, these are just average sizes, so lengths and diameters will varying a bit within the tub.
  9. BlueBoy69

    subsonic 308

    Don't try to get too close to the speed of sound (*) as you can still get shockwaves forming on the projectile even though its subsonic and they can make that characteristic supersonic crack you want to avoid. This is due to the flow over the projectile being, at certain points, supersonic, even though the projectile's subsonic. This results in the formation of shockwaves normal (at approx 90°) to the projectile's surface. Also, as the temperature drops, what was subsonic becomes supersonic (** & ***). * = 340.27 m/s (1116.4 ft/s) at internation standard atmospheric (ISA) conditions (sea level standard reference point +15°C, 101.325 kPa, 0% humidity) ** = 331.30 m/s (1086.9 ft/s) at 0°C. *** = 328.25 m/s (1077.0 ft/s) at –5°C. Some image examples below of a bullet, then for a wing, transitioning from subsonic to supersonic. Oh, and a video showing a wing going supersonic, this visualised using soap films. This change in the positions of the shockwaves formed as the object moves from subsonic to supersonic, results in a massive change in the centre of pressure. As far as I'm aware this is the primary reason for transonic instability problems.
  10. BlueBoy69

    52gr eld .223

    They would seem to expand on impact with water-filled jugs. Try something similar at ranges from 100 to 300 m if the expansion at longer distances needs to be checked. That or buy some ballistics gel for a more realistic 'flesh-like' test medium. https://www.defensible.co.uk/
  11. BlueBoy69

    .357 magnum question

    Haven't really reloaded for the 357 Magnum since they took away my Colt Python (1998), but here's my two pennies worth. Enforcer is for full power magnum pressure loads really, like 2400, H110, and W296. So unless your lead bullets are hard-cast and gas-checked, I wouldn't use this powder with them. The powder is suited to the aforementioned type of bullet, or a jacketed. It would be best to get a multipurpose type of powder, like Unique, N340, and load the rounds those bullets are used in to 38 Special level pressures.
  12. BlueBoy69

    110grn .308 load data

    If you only have H4895, there's data in the Hornaday manual (12th edition) I have, data below. Starting load = 43.9 gr Starting velocity = 2,700 fps Max load = 51.9 gr Max velocity = 3,200 fps For note, this is from a 22" 1/12" twist barrelled Winchester Model 70 rifle. There's also data for the Barnes 110 gr TSX on Hodgdon's reloading data centre. http://www.hodgdonreloading.com/data/rifle You could use that as a starting point, but be aware, that's an all copper-alloy bullet and they commonly have a higher shot-start pressure and bore friction. The Vihtavuori and Western Powders manuals have quite a few loads for the Hornaday 110 gr V-max, but you'd have to get another type of powder. https://blog.westernpowders.com/wp-content/uploads/2019/04/WPHandloading-Guide-7.0-Web-REV.pdf https://www.vihtavuori.com/reloading-data/rifle-reloading/?cartridge=30 https://www.vihtavuori.com/wp-content/uploads/2020/01/Vihtavuori_Reloading_Guide_2020_ENG_www.pdf That's all I could find for a quick check.
  13. Ah, ensuring an accurate muzzle exit for triggering instrumentation, the bane of my first job. When using Doppler radars we generally used flash, though sometimes an acoustic (external pressure) gauge, or simply the increase in the radar signal. The problem with small arms, and for my old job proof shot and other similar brick-like projectiles, is that the projectiles have very high drag. If you are a few milliseconds out in your triggering it can totally screwup the calculation of the muzzle velocity (MV). Even for low drag projectiles, it can cause inaccurate MV calculation. If you are flash-radiographing, or taking high-speed digital photos of the projectile in flight, end up partially or totally missing the projectile. This is not good if the projectile fired costs tens, or hundreds of thousands of pounds, or they only have a few of them. For many small arms, a flash detector would seem to be best, as it's non-contact and simple to use. The problem is that it's susceptible to preflash and no good for revolvers though due to the cylinder gap and the rather copious amount of hot gas escaping from the cylinder gap before the projectile exits. Acoustic detectors would seem the next choice, but they can have similar pretriggering problems, need to be adjusted to metrological conditions and have the distance offset accurately measured. Using the increase in the radar signal to trigger the device has many problems, such as being is susceptible to pretriggering from noise, or other radar signals, and for small guns, especially with suppressors, late or no triggering. I did use other triggering methods, such as ionisation probes, make wires, break wires, foil screens, pressure gauges, radar, and strain gauges. The best for guns was a strain gauge or pressure gauge near the muzzle. The former glued to the barrel surface, the latter, in this case, screwed into a threaded hole in the barrel. Not really practical for home use. I never used and accelerometer to trigger devices for measuring the MV of a gun. I doubt it would be accurate enough frankly as how do you know at which point the bullet has exited?
  14. BlueBoy69

    Measuring Case Volume

    You don't mention anything about the primer. Are you plugging the pocket, using a fired primer, using an inert primer, or an unfired primer? If you are going to this level of detail not accounting for the volume in the primer area would seem to be a bit neglectful. At a guess, a fired primer would be best. This accounts for the loss in volume due to the firing pin indentation, and the increase in volume due to the combustion of the primer composition. Some of its combustion products are soilds, but I can't remember the exact ratio of soilds to gases.
  15. Sorry, I've no idea what you're talking about? Calculating the volume of truncated cones, etc., so you can work out the volume occupied the 'base', not nose of the projectile when inserted into the cartridge case is not everyone's cup of tea.

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