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BlueBoy69

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  • Birthday 09/13/1969

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  1. BlueBoy69

    Reloading data

    As mentioned Shotgunner, taboo! I've researched this in detail and the difference in nitroglycerine (NG) content between some of the taboo powders and those that are supposedly fine is often a few percent, not tens of percent as in high-NG content double base (DB) propellants. Also virtually none of the manufacturers state the propellant flame temperature which is the primary deciding factor in barrel erosion, with pressure coming second (see later equation). All they state, if you are lucky, is the heat of explosion and this cannot be equated directly (easily) to the flame temperature. It is possible to convert one to the other, but this requires additional details, such as the chemical composition of the propellant and its combustion products, which are even harder to find. erosion ≈ (Tex)7 × (pmax)5 × (mc)1.5 × (vo)1.4 Tex= flame temperature, Pmax= peak pressure, mc = charge mass, and v0 = muzzle velocity. The DB propellant is of course affected by the type of nitrocellulose (NC) used in its manufacture. Highly nitrated NC having a highly energy content and flame temperature that lower nitrated NC. Never be fooled by the statement that NC is of one type only, nor that is energy content or flame temperature is of only roughly one value. Similarly and ignoring the shape (morphology) of the grains, no two single base propellants are the same, they all have different properties. This due to the type of NC used and the additives, which may be inert, or contribute to the combustion process. The additives being items such as the plasticizer and stabiliser mix, along with a coating of graphite to lower the effect of static charges on the grain. Additional common additives may be a flash suppressant and/or decoppering agent. The grain shape of RS rifle powders are single perforated tubes, as are many other powders. This leads to a generally neutral burning powder, i.e., its surface area remains roughly constant through the ballistic cycle. This because, as the outside surface area decreases, the inside increases. In RS’s extruded impregnated (EI) powders, a shallow outer layer the grain surface (included the central tube) is impregnated with NG, this then coated with a deterrent and then graphite. Their propellant EI formulations are commonly almost exactly the same, other than the deterrent depth/type and the grain size. When the grain burns, the surface (external and within the tube) regresses, the deterrent layer is first consumed, then the thin NG impregnated layer. Once this NG layer is consumed, all that is left is the generally lower energy nitrocellulose, plasticizer and stabiliser mix. The tailoring of the deterrent layer controls when the propellant starts burning and where the majority of the grains are when they start to combust. As with most granular propellant based systems, the propellant is moved and compressed by both compressive pressure pulse from the primer ignition and the gradual pressurisation of the grain bed by the gases produces by the portion of the grain that is already burning. This results in the projectile (bullet) being pushed from the chamber(case) before some of the propellant has yet combusted. For RS EI propellants, the deterrent, the NG layer and this movement means the combustion of the propellant is the same as most common propellant. This results in the propellant burning and achieving its maximum pressure at a distance further down the tube (barrel). It also means that time period that the peak pressure is present is longer too. Simplify the area under the pressure/time, or pressure/motion) curve graph is larger, so more work is being done in the same volume of the barrel. It is this additional work and hence energy deposited within the bore of the barrel that potentially causes the increased erosion, not simply increased flame temperature or heat of explosion. For note, in general, around 30% percent of the propellant energy ends up in the projectile (its translational (velocity) and its rotation energy), 45% in the powder gases (the velocity and temperature) and the rest goes into heating the barrel, partly by direct heat transfer and partly through friction. Obviously as the tube length increases, less and less energy ends up in the exiting gases, this ending up in the projectile and barrel. As mentioned in previous posts, the movement of the propellant bed and hence projectile can, in some cases, has serious effects on the internal ballistics and accuracy of the system. This proved and covered in detail by many US Army Research Laboratory and other labs research papers, even if people here choose not acknowledge it.
  2. BlueBoy69

    Reloading data

    Hmm, as RL15 is stated in Alliant's MSDS to contain diisopentyl phthalate, then it well may be banned from import as a reloading powder under the REACH directive. So yes, best to find something that is REACH-compliant to use instead.
  3. BlueBoy69

    Reloading data

    I think it should OK, just you might need to add some more in, as per what 'palmarifle' above mentions for his loads. As always, carefully work up your load. Personally, I use the devil's powder, RS60 with my 123 grain and heavier loads, but it's taboo to use it here. Patent and other reference material on for RS60, such as its material safety data sheet (MSDS), states it contains about 16% nitroglycerin (NG), which compares quite closely to many double base (DB) ball propellants, but nowhere near Vithavouri's and other manufactures DB high energy content propellants that contain up to and greater than 30% NG. Its NG level is around the same as that stated for the often now recommended, due to European REACH policy, IMR Enduron powders (their MSDS stated an NG content of 5-15%), but heigh-ho and c'est la vie and all that.
  4. BlueBoy69

    Sierra Introduces New 6.5mm 150 gr MatchKing Bullet

    I think it's simply the length Dave. The new bullet is blooming long. I don't have the exact length, but if you look at the Sierra rifle bullet page and compare the lengths of the 6.5 mm bullets, you can see; of course this does depend on them being to scale. Sierra rifle bullet page Ignoring the 6.5 mm 155 grain LR SMK (9570), that doesn't seem to be sold now (was it very popular?), most of the 155-160 gr bullets used in the 6.5x55 are no longer, or even shorter than the 142 gr SMK, as they tend to be hunting bullets. So these are even more stable, as the weigh has increased but the length has not increased and in some cases, decreased. This as (gyroscopic) stability goes up with the mass, if the projectile stays the same length and travels at the same spin rate. So, unless the rifle has a 1:7.5" twist as recommended, there may be stability problems from the common 1:8" twist barrels. Though a bit heavy for the 6.5 mm Creedmoor, their load data gives top speeds in a 24" tube, around 2,700-2,800 fps, so no slouch. Through a longer tube (26-28"), this range should be more easily attainable with the right powder selection, but it's pushing it to it's limit. I agree with you though, it's perfect for the 6.5x284.
  5. For those who havn't already seen the news on Sierra's blog and other pages. As the title states, Sierra have brought out a new heavier, 150 grain, 6.5 mm Matchking (SMK) bullet. Links below. Sierra blog link Updated load data for the 6.5 Creedmoor that includes the new bullet (PDF) Sierra product page This provides far lower drag (G1 0.713 at 1,760 fps and above) than even their 142 gr (G1 0.626 at 2,850 fps and above) and lower weight SMK bullets, along with all of Berger's and Lapua's 6.5 mm (0.264") offerings. Looks like the gunsmiths will have a field day though, as it needs a 1:7.5" or greater twist to stabilise it
  6. BlueBoy69

    Reloading data

    There's data in the Reload Swiss manual (link) and on their webpage (link) listing RS62 with a 123 grain Lapua Scenar. You can use this as you starting point. Looking at their data and then plugging this into QuickLOAD results in a pressure and velocity that comes near, but is not the same. Both are predicted higher in QuickLOAD than the Reload Swiss pressure tested load. Even so, I'm not entirely sure why they load so low with this powder and bullet combination, as the max pressure they list is only 2,395 bar (34,740 PSI), compared with 3,200 to 3,950 bar (46,500 to 56,500 PSI) for most of their other 6.5x47L loads? Even going by QuickLOAD, you can go to a 102% fill (the max fill listed by Reload Swiss only being about 92.6%) and still stay within the safe, but not max pressure levels. In either case, RS62 does seems to be a little slow for this particular bullet/case, but you may, or some other person, have already got it to work.
  7. BlueBoy69

    RS62 query with 6.5mm Creedmoor

    I think it would be best you post this as a separate thread and not take this thread off its intended subject. Once that's done, I or anyone else with QuickLOAD, will be able to post the data you require.
  8. I think you'll find its the Soviet era 12.7x108 as used by the DShK and other Russian HMG, not the 50 BMG. That or the 14.5x114 used by the KPV HMG (KPVT vehicle version and ZPU AAA installations), or the good old 23x152B used by 2A14 cannon (as used by the ZU AAA guns and ZSU SPAAGs). Popularity of ammo is probably actually the the 7.62x39, then the 7.62x54R, then 5.45x39, then the big boys. They're also been seen using Western infantry personal weapons, so 5.56x45 and 7.62x51.
  9. BlueBoy69

    .338 Lapua Magnum

    A friend of mine at work has a Barrett bolt action in the calibre and doesn't reload. I could ask him if he want to sell his old brass if you want? Oh and as far as I can remember, he only buys Lapua ammo.
  10. BlueBoy69

    Marlin Cowboy Lever

    I've got a nice original and rare Marlin 1894 CL for sale, but its in 32-20 WCF and 6-shot. http://ukvarminting.com/forums/topic/40071-marlin-1894cl-32-20-wcf/?p=315561
  11. I don’t use Berger’s program for calculating the stability of plastic-tipped and other bullets. This is because Berger’s program generally underestimates the value. It is fine for standard open-tipped match OTM) boat-tailed (BT) bullets though, just not good with the aforementioned plastic tipped, OTM or tipped flat-based bullets (they state this on their calculator page and pass you on to another page), pistol and cast bullets. For plastic-tipped BT bullets, I use the web-based JBM stability program, as its calculations seem to be far more accurate. Well, far better at predicting stability that type of bullet than others. The program can be found at the link below. http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi Putting exmarksman9870’s details into the JBM program, so: 308” calibre; 175 grain weight; its overall length 1.384” (details from an JBM web databases and QuickLOAD); its plastic tip 0.200” (as per the bullet); 2,500 fps MV; 1:12” twist; 18° temperature; and 1013.25 millibars standard sea-level atmospheric pressure – gives a stability factor (Sg) of 1.624, so quite stable! Putting the figures into Berger’s program, plus a G1 ballistic coefficient of 0.535 , gives an Sg factor of 1.21, so only marginally stable. Quite a difference. Who’s truly right, well unless we have access to proper decent Doppler radar with spin analysis (the Labradar is OK, but its software and tracking range are limited), we aren’t going to be able to calculate accurate figures. For further reading on the stability of plastic, and other bullets ballistics, try the papers or books listed below: A Stability Formula for Plastic-Tipped Bullets - Part 1 (2014); A Stability Formula for Plastic-Tipped Bullets – Part 2 (2014); Aerodynamic Drag and Gyroscopic Stability (2014); Computational Ballistics III (2007); Gyroscopic Stability of Open Tipped Match Style Rifle Bullets (2014); and The Aerodynamic Characteristics of 7.62 Match Bullets (1988). If you can’t find them on the web, I can upload them, and any others on ballistics that you might like to read, to a folder on my Google Drive. BB69
  12. BlueBoy69

    Transparent moderators in slow motion

    Great video and great blog. It's well worth watching many of their other videos.
  13. BlueBoy69

    Quickload advice please

    No it doesn't unfortunately. The newest version of QuickLOAD is 3.9. This adds nothing other than getting the software to install properly on Windows (spyware) 10. http://www.neconos.com/QuickLOAD-Windows%2010.htm The latest data update (bullets, cases, powder) was version 3.8. This does not have the new IMR powders in. The list of supported powders, etc. that can be found in version 3.8 is below. https://cdn.shopify.com/s/files/1/0274/0391/files/quickload-3.8.pdf
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