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Stonepark

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  1. 1.27 inches for No6 and 1.45 inches for No4 into ballistic gel at 50 yards according to Shotshell Ballistic Calculator What was the pellet count within 30 inches at 40 yards for your favourite cartridge for each barrel? Nominal measurements are a guide, not a definitive and until you pattern the gun, with your favourite cartridge, it could be shooting cyl/cyl or full/full or anywhere inbetween. Before trying a myriad of cartridges, take your current prefered cartridge and pattern it, you might not have a problem.
  2. Stonepark

    Yokohama Geolandar Tyres 235 70 16

    At 5mm on an all terrain, they are done.
  3. Don't know, but it will be vegetable derived, but the reason they are releasing these now is that the patents for Injection Moulded Polymerised Starch ran out in 2016.
  4. Looks like a mix of polymerised starch , glycerine, wax and one or more binders and pectin with other substances such as amylose to enable a quick breakdown of binders.
  5. Stonepark

    Prince Philip off the road for good

    Suprisingly it can happen at quite low speeds, due to the high centre of gravity, a strike below this, by a vehicle with a low centre of gravity, going upwards is often the least resistive path.
  6. Photo wad is plastic made from maize, rather than plastic made from oil. By degrade they don't mean used up and converted into other forms but break up faster into small pieces, exactly what the various bans in plastic is trying to prevent to protect the marine environment.
  7. Stonepark

    SSB 150 Load Data

    Maxam themselves only suggest 31.6gr for their 32g load for 415m/s and 600bar. http://www.maxamcomponents.com/en/outdoorsbrand/componentes/products/powders
  8. Stonepark

    SSB 150 Load Data

    Thst 3 inch load is using a **** lot of powder for only 535 bar, looks like the change in primer has a large effect on pressure in this load.
  9. Stonepark

    falcon prarie

    Will be the pair of o rings on the filler valve as if not used regularly they dry out and lose pressure, last time my fn19 went, parts (replacing all seals) were £6, labour £30.
  10. Stonepark

    Article on Fibre versus Plastic

    If you look at #### pricing, for fibre, wads are similar in price to plastic (£25 v £21 per thousand) but over powder card is £7 per thou which is not needed for plastic, add 10% more powder and you easily get £10 per thousand more in retail cost or £5 per thousand to manufacturer.
  11. Stonepark

    Air rifle

    fALCON FN 12 LIGHTHUNTER
  12. Stonepark

    My 1/6 scale RC Challenger 2 tank

    At 1/6 scale, it would be 10 bore as original is 120mm smooth bore
  13. Stonepark

    Soft 20

    Just Cartridges are doing a 20b CSP Lite 21g 7.5 diamond shot low recoil - may be worth a look.
  14. Stonepark

    Sonic Shooter's Aid earplugs

    Unfortuneately the chart is only good for use in constant sound areas, not representaive of how the plugs deal with impulse noise which is what we deal with when using firearms and the noise they use to test for SNR does not have this impulse element. The paper from HSE which your chart came from specifically pointed out that most users did not adequately identify their requirements due to a lack of understanding or that of the hearing protection had vaious options and how these worked and dealt with various issues such as fit, placement, sound source and protection requirements. Sonics (similar to other filtered ear plugs), specifically are designed to protect from impulse noise and do this by having a small opening (approx 2mm) and the valve which closes with pressure. Even as you suggest should the valve not work effectively, just having the small hole protects significantly against the impulse noise. Have a look at the paper on "Performance of Hearing Protectors in Impulse Noise " by Buck, which deals with this difference between constant noise and impulse noise. I previously quoted Surefires figures from their EP4 manual sheet (and given how litigeous the USA is, I have little doubt they are exaggerated), which clearly show that with impulse noise when the tunnel/filters are open (circa 2mm hole) 28db and when the tunnel/filters close 40db both of which is perfectly adequate for pistol and shotgun use. Given the Sonics are mid way (SNR18db) between the uncapped EP4 (SNR 12db) and capped EP4 (SNR 24) in their open valve form and have a small holed which is valved, they will sit somewhere about 34db against impulse noise which is adequate, even though for constant noise their SNR of 18 may be inadequate.
  15. Stonepark

    Sonic Shooter's Aid earplugs

    The peak sound pressure level (SPL), spreading of pressure wave and other physical characteristics of the impulse noise from weapons were studied in actual shooting conditions for assessment of gunfire noise exposure. Additionally, the attenuation of SPL by hearing protectors was measured with miniature microphones to evaluate protection efficiency in real shooting conditions. The peak SPLs at the shooter's ear ranged from 132 dB (miniature rifle) to 183 dB (howitzer). The spectral content of the main part of the acoustic energy was less than 400 Hz (peak 16-100 Hz) for large-caliber weapons and 150-2,500 Hz (peak 900-1,500 Hz) for small-caliber weapons (rifles). The safe distances from the noise source (less than 140 dB peak SPL) were 50-200 m for large-caliber weapons. Rifle impulses (assault rifle, caliber 7.62) had a peak SPL of 154 dB at a distance of 4 m from the muzzle. The peak SPLs of different explosives ranged from 125 to 185 dB at distances of 10 to 300 m. In rifle shooting, the attenuation efficiency of earplugs (16dB) or small-volume (thin) earmuffs (17 dB) was not sufficient and their use as sole protectors cannot be recommended. Instead, large-volume earmuffs should be used. Impulses from pistol and shotgun were fairly effectively attenuated both by small-volume and large-volume earmuffs.
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