New cartridge design

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by BountyHunter, Jun 5, 2007.

  1. BountyHunter

    BountyHunter Writers Guild

    Messages:
    4,803
    Joined:
    Jun 13, 2007
    http://www.superiorballistics.com/index.html

    well now for all the ballistic experts this is an interesting concept of short fat cases and elliptical shoulders for more efficiancy, more velocity and less barrel heat.

    BH
     
  2. jwp475

    jwp475 Well-Known Member

    Messages:
    2,595
    Joined:
    Feb 4, 2005
    Do you acctualy believe the claim of increased velocity without increaseing the powder capacity?....[​IMG]
     

  3. Buffalobob

    Buffalobob Writers Guild

    Messages:
    5,085
    Joined:
    Jun 12, 2001
  4. James Jones

    James Jones Well-Known Member

    Messages:
    2,854
    Joined:
    Jul 1, 2002
    This is actualy an old concept , it was done years ago with the 348 winchester case by shortening it and radiusing the shoulder. The basic idea is like the Weatherby shoulder , kinda saying that the radius can handle more pressure and direct the pressure to the case neck makeing it more effeciently.

    I think that this idea is that the primer blast is bounced around inside the case at accurate angles to make the powder burn more effeciently hence making for more velocity with less powder.

    My personal oppinion is that sombodys just wanting to stick his name on a case and have a claim to fame. I'm gonna have to be an eye witness to test compairing this case desgine to say an Ackley improved desgine of the same volume and powder charge diameter with the same bullet out of the same barrel before I accept it as being supperior to whats already out their.
     
  5. royinidaho

    royinidaho Writers Guild

    Messages:
    8,853
    Joined:
    Jan 20, 2004
    bb, how'd you scrounge that up? I can't find anything more than 2 days old. /ubbthreads/images/graemlins/crazy.gif

    The above referenced link + a thing that Kirby was doing, got me going on the "flash tube" idea. Which by the way is about to start up again. Initial trials show there there are noticeable differences w/the Frontal Ignition but I gotta get a decent method of measuring barrel temp over the length of the barrel.

    RE: the above link and elliptical shoulder design

    I wonder how much of the primer flash makes it through how much of the powder in the case?

    From my experience I think that I can see in that web site a whole bunch of initial excitement (been there and done that) with some possible trials that probably gave results that were no worse than conventional designs and possible some a bit better (but compare against this Link and what do you get?)

    It seems like the shooting world just needs more superior craftsmen to bring the current cartidge designs up to their potential in shooting platforms, then someone can do something innovative to take things to the next level.

    Or it may all be in the marketing as with the Weatherby shoulder design???
     
  6. jwp475

    jwp475 Well-Known Member

    Messages:
    2,595
    Joined:
    Feb 4, 2005
    Frontal ignition does appear to have merit in not heating the barrel as fast as rear ignition. Frontal igintion is used in artillary shells.Frontal ignition does not increase velocity with the same amount of powder.As I recal Fiftydriver stated that it acctualy took a little more poweder to get the same velocity as rear ignition, in his experimntation with this system..........[​IMG]
     
  7. BountyHunter

    BountyHunter Writers Guild

    Messages:
    4,803
    Joined:
    Jun 13, 2007
    Ha, knew this would kick the feather pile.

    supposedly the testing was done at Norma's facilities and been actively used and written up in several magazines.

    However, there is an interesting phenomena that we have seen with the 300 WSM. In the 1k BR game, a standard 300 Win mag barrel will last 1000-1400 rds max, while we are getting 2-3x that with the WSM barrels.

    BH
     
  8. jwp475

    jwp475 Well-Known Member

    Messages:
    2,595
    Joined:
    Feb 4, 2005
    Less powder equals longer barrel life,also less velocity.....[​IMG]

    There 5000 fps is with a 20 grain bullet,who shoots 20 grains bullets in this caliber?.......[​IMG]
     
  9. jb1000br

    jb1000br Well-Known Member

    Messages:
    1,307
    Joined:
    Jul 8, 2003
    Forward ignition was tried at Williamsport by several back a ways...no one uses it.

    Till you get the primer tube in there you REALLY cut your case capacity...

    YMMV,
    JB
     
  10. royinidaho

    royinidaho Writers Guild

    Messages:
    8,853
    Joined:
    Jan 20, 2004
    jwp & 1000br,

    Here's what I've learned so far. All tests in 338 Win Mag. REM 700 Sporter.

    For equal amounts of powder velocity and pressure is lower with FI.

    If the load is MAX for FI, don't shoot it w/out the flash tube.

    For equal average velocities SDs and ESs are smaller with FI.

    Pressure curves w/FI did not show the small pressure spike just prior to the bullet exiting the muzzle. W/o the FI it almost always appeared.

    Temperature test(feable attempt w/poor sensor(s): Heat appeared to concentrate at or just ahead of the chamber then flow forward. With conventional ignition, the whole barrel length heated up fast.

    Felt recoil was definitely less w/FI but not enough to make it a real feature.

    Powder capacity taken up by the flash tube can be compensated for by using appropriate. For example in my 270 AM and conventional ignition using US869 give about 90% or so load density (if I correctly understand what LD is?). 90% LD leaves just enough room to make 100% LD with the flash tube installed.

    Having said all of that, here's where I am. I was excited to rebarrel the 338 Win w/a 338 RUM and go to the next level. I got the 338 RUM shooting 300 SMKs @ 2735 +/1 FPS and clover leafs @ 200 yds. So why mess with the FI /ubbthreads/images/graemlins/confused.gif

    FI may be an advanted IF all the powder could be made to burn in the case and gases only entering the throat and barrel. Maybe throats would last a bit longer.
     
  11. Mikecr

    Mikecr Well-Known Member

    Messages:
    4,264
    Joined:
    Aug 10, 2003
    Front ignition is as old as Gibbs, and each of your findings match his.
    It simply comes down to more powder burning in the case, rather than following the bullet down the barrel.. Less pushed with the bullet, contributing to recoil, and burning off.. Less powder blasting of the leade.

    The powder column of a WSM/WSSM is too wide to follow the bullet well. This causes similar(but less) gains as that of front ignition.

    I'd be interested in your application method.
     
  12. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

    Messages:
    6,848
    Joined:
    Jun 12, 2004
    This is interesting stuff, certainly not new, it has been done over and over for the last 50 yeards and the military does it with large artilary shells, at least they used to.

    I tested Front ignition in my 7mm AM and a bit in my 270 AM. Standard performance with both is a 200 gr ULD RBBT loaded to around 3300 fps with around 105.0 gr WC872 in the 7mm and for the 270 AM average velocity is generally in the 3375 fps range with around 102.0 gr WC872.

    These are average numbers with 30" barrels.

    When I tested these two rounds, same rifles, with front ignition, I found several interesting things.

    First lets talk about the 7mm.

    I found with the 7mm AM based off the 338 Lapua case that this worked best if the cases were fired once with full pressure loads before using installing the ignition tube. Why? Well, on the first firing of any case the case head is going to expand more then it will from that point on given we are using comfortable working pressures.

    I found that if I installed a flash tube in the virgin cases and fired them, in nealy every instance, the tube would be extremely loose after this firing and several were flat out gone.

    When I tested with once fired cases, this did not happen nearly as often. Some were loose but only 1/2 rotation was needed to snug them up again.

    Performance was very similiar to what I was getting with standard ignition. I would say top end loads using FI were 50 fps faster at most. It did however take up to 5 grains more powder to reach this top end velocity. The reason is simply, when you are using a standard ignition system, the bullet and powder charge weight need to be combined to determine the resulting chamber pressure because the powder is being forced down the bore to some degree along with the bullet.

    With the forward ignition, this is not the case. I would estimate 90% of the powder never leaved the case as it burns. So with standard ignition you have a 200 gr bullet plus 105 grains of powder for a total payload of 305 grains. Over 30% more then with front ignition.

    I also found that barrel temps were FAR lower using forward ignition then with standard ignition. To that same point, fired cases with forward ignition were much hotter to the touch then standard ignition rounds, again, the reason is obvious, the powder is burning in the case, not in the bore.

    This is the reason the throat lasts so much longer.

    With the 270 AM, I had some problems getting the sold Rem cases to hold the threads on the flashtubes. I tried some permanent thread locker and that helped quite a bit but personally, I do not care for this ignition method using these cases. Results however were nearly identical to the 7mm AM results.

    I personally feel that forward ignition is best suited to larger case capacity rounds then most of us deal with on a regular basis. I think rounds such as my 338 Allen Magnum would get a huge boost in barrel life using this method of ignition and I hope to test that theory out here soon.

    For smaller chamberings, the benefits are certainly there but practicality issues come into play in my opinion and in most instances, front ignition is not practical for many conventional chamberings.

    Just my experience.

    Kirby Allen(50)