6.5 Prometheus (6.5 PRO) 140 gr. 3700 fps

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Swamplord, Nov 11, 2012.

  1. Swamplord

    Swamplord Well-Known Member

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    Prometheus.... the Bringer of Fire..... is reborn !

    Bullet Weight:
    140 gr

    Muzzle Velocity:
    3700 fps

    Muzzle Energy:
    4257 ft-lbs



    AmmoGuide is now... "Interactive"!



    The original case dimensions were created in May 2011 for the "7.62 PRO" then re-designed and necked down to 6.5mm in February, 2012 by Pro Martusheff specifically for the Sako TRGS M995 action. The idea evolved in the spring of 2011 and became reality when KRG Welcome to KRG made a stock for the SAKO M995 that uses AICS "CIP" length 5-10 round magazines, The parent 338 Norma Magnum was perfectly suited for this action and and AICS mags.

    Given the amount of powder it burns for the 6.5mm bullets, the wildcat was originally named "6.5 Prometheus" to pay homage to the Greek Titan Prometheus (the bringer of fire) who stole fire from Zeus and gave it to man. The short name for it is 6.5 PRO (Precision Rifled Ordnance). Basically it's a 6.5mm cannon that brings fire. The shoulder was changed to 35° and neck length to .342", the base of the case was retained at .589", the shoulder pushed forward to 1.9549" , I wanted a bit more taper in the case for extraction when shooting high pressure max loads and the width at the top of the body is .570" giving the case a .019" taper
     

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    Last edited: Nov 11, 2012
  2. submoa

    submoa Well-Known Member

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    Wow that things a lazer beam shooter
     

  3. lazylabs

    lazylabs Well-Known Member

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    Since I am being lazy and your bragging.............haha............ how much faster is this than the 6.5 WSM?
     
  4. submoa

    submoa Well-Known Member

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    Well if you hot rod the win mag you can get around 3300 or so and this thing he is saying 3700 so wow its fast ;-)
     
  5. Swamplord

    Swamplord Well-Known Member

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    The case water capacity is a typo in the above diagram, it's more like 105 gr. water....

    This wildcat is part of a multi barrel switchbarrel rifle project based on a Sako TRGs M995 action and the KRG Whiskey 3 Chassis, all based on my designs off the 338 Norma Mag case,

    It started in 2011 with the "7.62 PRO" short for Precision Rifled Ordnance, and yes it does mean rifled cannon........ It will match and exceed anything the 300 Rum can do, designed specifically for bullets 200 grains and heavier seated to the base of the neck with a neck length of .375"
    32" Rock Creek 5R 10 twist bbl and WS2 coated Berger 215 gr bullets, velocity of 3250 fps

    back when the 300 WSM first came out , I immediately wanted to neck it down to 6.5mm but there were screams of "OVERBORE" and all sort of nonsense that made me cancel the project,
    now there are hundreds of shooters enjoying the 6.5 WSM with good reason, I studied and messed with numerous 6.5's but none were satisfactory, after learning of
    Kirby Allen's 6.5 AM, I was intrigued but could not get a reamer made due to some kind of "proprietary" BS, I decided to mess with my 7.62 Pro and neck it down to 6.5mm, the 6.5 Prometheus (6.5 PRO) is ballistically identical to the 6.5 AM but can be pushed 100 fps faster

    the 4th bbl for the project is the ".375 Mjolnir" ( the Hammer of Thor) which will easily outpace the H&H and Ruger and is right on the heels of the .378 WBY Mag with a lot less powder.

    the 5th bbl will be in a .416 or .458 and is yet un-named (crunching numbers)

    I will not be doing anything on the 7mm and 270 calibers, simply because the 6.5 and 7.62 calibers will do anything and everything better than those can, ( sorry guys, just my opinion)
    the 338 Norma mag is just fine in it's original design and is the very first barrel installed on the rifle...a Brux 9.5 twist 30" fluted Rem. Varmint contour bbl......

    I am certain there are those that will shriek like little girls about the "overbore condition" of my 6.5 Pro, the best way I can try to explain is... barrels to me are like tires on my truck, when worn out I will replace them !!
     
  6. FEENIX

    FEENIX Well-Known Member

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    100 FPS faster than 6.5 AM, holly crap that's blazing fast. gun)
     
  7. Outlaw6.0

    Outlaw6.0 Well-Known Member

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    Can I get an AMEN!! I'm a 6.5WSM shooter & have experienced the gauntlet of Overbore war cries :D THE HEAVENS SHALL RAIN FIRE! ALL IS LOST!!! LMAO

    It's nice to see someone that shares the same mindset that I do. When it's dead, it's dead. Buy another one:rolleyes: THe 6.5PRO is a beast, setup with a Melonited barrel & mabye some BN coated bullets.... yep, I like it!


    t
     
  8. mikehaas

    mikehaas Member

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    As the owner of AmmoGuide, I can assure you that the 102.9 gr. Case Capacity listed in the AmmoGuide data is NOT a typo.

    First, understand that water is extremely dense and it doesn't take much of it to make the 2 grains difference you perceive (about 2% of the total volume in your wildcat's case, actually).

    Secondly, 2% (the difference between 105 and 102.9) is an acceptable tolerance for even high-precision instrumentation. In my Navy days as a Nuclear Electronics Technician, the multimeters we used to measure/calibrate voltages of systems directly affecting the reactor core only had to be within 3%.

    Thirdly, "case capacity" is a particularly elusive parameter to nail because it is subject to many real-world variables when being measured. Any 2 people trying to measure it are unlikely to come up with the same answer. The temperature of the air & water, altitude, how many times the case has been reloaded, whether the case is clean inside, whether the case has been fired, resized or even HOW it was resized... these and even more factors cause "case capacity" to vary when measured empirically. You may consider "105" to be THE NUMBER but the relevance of your result to the rest of the world is reduced because of this variability.

    Plus, since you shoot a wildcat, your cases are certain to have been fired at least once and/or formed in a die before measuring. There is no such thing as a "factory virgin" case in 6.5 PRO - your volume measurement will alwys be affected (slightly) by the specifics of either your rifle's chamber, die size or both.

    AmmoGuide calculates the internal volume of the case in grains of water in a uniform manner that assumes virgin, unsized, unfired brass. Therefore, the website's values are much more useful in terms of comparison with other case capacity values on the website because all variables have been removed in the estimates for all cases.

    Mike Haas
    Owner, AmmoGuide.com
     
  9. mikehaas

    mikehaas Member

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    BTW, the .347" neck-length in the AmmoGuide diagram isn't a typo, either, despite the fact that your description notes a .342" neck-length.

    In the (second set of) dimensions you submitted to AmmoGuide, .347" is what the neck-length works out to (neck-length = case-length - top-of-shoulder). Apparently, either your textual description or submitted case dimensions still aren't exactly correct.

    Mike Haas
    Owner, AmmoGuide.com
     
  10. tim jurczak

    tim jurczak Well-Known Member

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    Swamplord, have you actually fired this chambering? I don't ask you this because I'm disputing your claims but rather to see how user friendly it is overall. Muzzle blast powder selection and fouling. I have been using a 6.5 STW and really love it although I'll be the first to admit it can be a real A-HOLE at times too.

    Pressure spikes, weird flyers, and with the real slow powders I get 80 FPS spreads. I assume it is because my 26" barrel is too short???

    When I had this rifle built I suggested to the gunsmith that I may like to have my rifle chambered in 6.5 RUM or 6.71 Blackbird and he said no. It is a lighter weight gun so I'm happy but I still wonder what could have been. On the other hand I'm debating whether I should double up for my heavy LR rifle and stay with STW for simplicity sake or go BIG! LOL


    Tim
     
  11. Swamplord

    Swamplord Well-Known Member

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    Mr. Haas, you are correct... the max overall case length is 2.502" and the base of the neck is 2.155" making the length of the neck .347" as you stated, the reamer print drawn up by Dave Kiff of PTG shows the exact same thing !!

    BUT .... the case is trimmed back to my specs of a .342" neck every time the cartridge is fired (if needed) and will be maintained at that length, the finished cartridge will always possess a .342" neck, that is why I repeatedly used the .342" neck length #'s ....

    The case capacity is a non issue as you stated, I'm certain the variation in the parent 338 Norma Mag and the 300 Norma Mag will give different case capacities and from different lots of brass and dates of manufacture, always does !!!

    I apologize for causing any confusion !

    I sincerely thought this wildcat would cause a bit of commotion, guess I was wrong,
    Seems that folks are more excited if the improvement in velocity gains is 100 fps or so,
    The 6.5 Prometheus might just be too fast and too flat shooting of a 6.5 for the LRH forum members, (is that possible ?) haha
     
  12. Rizla

    Rizla Active Member

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    This cartridge is just what I was looking for! Does anyone have any results from testing that I can sink my teeth into?
     
  13. 87predator

    87predator Well-Known Member

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    tagging in
     
  14. LouBoyd

    LouBoyd Well-Known Member

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    Considering a 264 Win Mag only has 82 grains case capacity and the Prometheus has 102 grains what do you expect for barrel life? Most 264 Win Mag barrels die of throat erosion in under 1000 shots.

    That's not to say you shouldn't build the 6.5 Prometheus.

    My candle burns at both ends,
    It will not last the night.
    But ah, my foes, and oh, my friends,
    It gives a lovely light.
    (Millay 1920)