Here are pdf scans of a year 2000 era manual for:
the ACCURACY DEN *I.C.C. UNIT
*(Internal Concentricity Comparator)
Ultrasonic Metal-Mass Detector
“The Vern Juenke Machine”
Original US LETTER size format ;and
VernJuenke_oringal LTR size version
resized A4 format
VernJuenke_resized LTR to A4 version
For something a little bit different here is a link to the OpenRocket source download. It’s a Java based program. Don’t expect exact ballistics software but you cna construct your own designs and use the Component Analysis function to see how changes affect the drag etc.
So here is a link to download the original MS Excel spreadsheet for Nose Cone Design.
I use a modified version myself to plot shapes that resemble long range target projectiles. If I can do it I’m sure those of you some knowledge of spreadsheets can come up with their own modified version. Follow the instructions and enjoy!
So if you’ve managed to magnify the outline of your ogive, effectively you can calculate the radius by measuring the meplat to the shank/ogive intersection. This will become your chord length W.
The Sagitta of the arc or height (H), is measured perpendicular from the midpoint of the chord W.
For double or multiple radius ogives there will be multiple chord lengths measure. Note also this method only works with ogives using a tangent and secant radius. The larger your outline is magnified the more accurate your measure will be, useful for those of us without an optical shadowgraph comparator or other such metrology equipment. Remember though you may have to contend with the parallax error depending on how you capture your image outline.
(link to Math Open Reference.)
Given an arc or segment with known width and height:
 |
where: W is the length of the chord defining the base of the arc H is the height measured at the midpoint of the arc’s base. |
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[1] Litz, Bryan 2011. Applied Ballistics For Long Range Shooting. 2nd ed. Cedar Springs, USA: Applied Ballistics, LLC.
[2] Sommer, Simon C. and Stark, James A. 1952 The Effect of Bluntness on the Drag of Spherical-Tipped Truncated Cones of Fitness Ratio 3 at Mach Numbers 1.2 To 7.4 Washington, USA: NACA Research Memorandum A52B13.
Here are some of our favourite sites…
J4 Precision Jackets
Recreational Software, Inc. (RSI)
Total Solutions Engineering (TSE)
Wild Dog Australia
Conservations & Wildlife Management Qld (Division of SSAA Qld Inc)
ICFRA (International Confederation of Fullbore Rifle Associations)
Queensland Rifle Association (QRA)
Australian Long Range Shooter Magazine
7mm.com.au
The G7L series of projectiles is Antipodean Industrial’s entry into the hand swaged projectile market. In principle, the G7L is a traditional long range (300y+) projectile designed for high levels of accuracy while maintaining supersonic velocity levels. |
| So why is the first projectile series called – ‘G7L‘? |
|
The ‘G7‘ part of the name refers to the preferred standard of drag curve, used to compare the form factor of a long range boat tail projectile, to estimate its ballistic coefficient (BC) at various velocity (and atmospheric conditions). Traditionally a G1 drag curve was used to perform various ballistic estimates based on the Mach number measurement (velocity including atmospheric conditions). The shape of the projectile used to create the G1 drag curve had a flat base and an ogive profile similar to a benchrest projectile. It has been found that the G7 drag curve more accurately predicted the various ballistic calculations (e.g. trajectory/velocity) at longer ranges. This is because the G7 drag curve was developed using a projectile with a boat tail and a more aggressive ogive profile; hence a closer representation to modern long range projectile shapes.Modern ballistic software is now available with BC calculations utilising the G7 drag curve as an option. The subscript ‘L‘ is acknowledgement of my bullet mentor Mr Gary Little for his assistance in developing this first range of projectiles for Antipodean Industrial. Gary Little produced a wide range of hand made custom projectiles under the company name of Little Bullets for many year in Australia. There is no doubt that without Gary’s mentoring skills, experience, industry contacts, generosity and patient personality, I would not have made any progress up the steep learning curve that is swaging bullets by hand. |
| Antipodean Industrial – manufacturing long range, competition quality projectiles |
| Antipodean Industrial is currently focused on manufacturing long range target quality projectiles for the local Australian market. The long ogive and boat tail ratios of our G7L series projectiles should instantly peak the interest of F-Class and Fly target shooters.Our goal is to manufacture a high quality local product for local shooters that is kept in good supply. There is no doubt that imported products dominate the market and have supported Australian shooters for over a hundred years due to amicable trade policy, and for that we should be thankful. Unfortunately though, due overseas demand and the size of our local market, we have been regularly let down with supply. Supply has either been delayed significantly from overseas release dates, expensive, random or non-existent in some cases.Initial results with the G7L series projectiles has exceeded our expectations even though we were just aiming for solid, reliable, competitive design. Once the G7Lbecomes established we will start developing more radical designs based on gilding metal jackets with lead cores, monolithic metals and other materials in various combinations. Essentially we are depending on strong Australian support for these individually hand swaged projectiles, because if you think our groups are small they’re nothing compared to our margins! |
