Originally posted by bj139
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6mm Grendel Group Design Project
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Originally posted by StoneHendge View PostLol - you bj'd it. In order to StoneHendge something, you must first perform world class feats, only to close out with a performance that would encourage the likes of Scott Norwood, Bill Buckner, etc. to come out of hiding.
I searched for 6mm Nosler and could not find anything.
It sounds like a topic for discussion.
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Regarding the Nosler, last time I checked, the space available for long noses is woefully inadequate even in the 22 configuration.
That is an issue Federal addressed in the Valkyrie.
A 6mm AR Turbo or Grendel would both still be better choices, however.
Yes, we can tweak any of the alternatives, but the Grendel case diameter and length are about as good as it gets when we constrain ourselves to standard AR15 receivers.shootersnotes.com
"To those who have fought and almost died for it, freedom has a flavor the protected will never know."
-- Author Unknown
"If at first you do succeed, try not to look astonished!" -- Milton Berle
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Originally posted by bj139 View PostIs this really worth doing for 0.020" less diameter?
In comparison, I do a 130 gr Norma GT with a G7 of .285 at 2800 out of my 24" 6.5 CM. I got over 2900 with factory Prime ammo (same bullet), but that stuff is hot. 2800 should be attainable with a 24" 6mm Grendel (even more with BFT's bigger case), so it really would be nipping at the S'more's heels - from a small frame.Let's go Brandon!
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Originally posted by bj139 View PostI know but is this difference large enough to have a meaningful improvement in performance?
(http://www.65grendel.com/forum/showt...l=1#post170192
Particularly, in view of the all-new CMMG ANVIL action, with their "take no prisoners" POWERBOLT ---
(http://www.65grendel.com/forum/showt...l=1#post165540)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
ETA:
(http://www.rifleshootermag.com/uncat...del-evolution/)
Enter: The 6mm Grendel Improved, the obvious next step in the Grendel Evolution --- and, with improved ballistic superiority, further separates us from the 6.8 crowd.
Last edited by SHORT-N-SASSY; 11-19-2017, 07:10 PM.
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As a bullet designer that has done a lot of work personally pushing different calibers to their upper limits.
You cannot look at case capacity alone. You also have to look at available pressure.
Available pressure and time under the pressure curve is what makes bullets go faster.
Of course that speaking of internal ballistics and not including rifling profiles, engraving friction and bore lining.
Another thing that is seldom mentioned is the width of the shoulder and how it effects pressure when looking for maximum performance.
This is why Weatherby used the rounded shoulder they did. I am working with a long range bolt rifle company that has went to the Weatherby shoulder in a new cartridge they are designing due to less pressure spiking.
This is also one reason the 30 Herrett can push a 125 grain bullet 2791 FPS from an 18in barrel. Now granted it does not have the high BC you all love, however it does speak to what I am pointing out.
There is a new TAC6 coming out on the 6.8 case.
With the current support by Nosler and Federal on 6.8 case based cats it may be worth looking at.
I do not think pushing the 6mmAR shoulder forward such a small amount will gain what your looking for.
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Originally posted by CavityBackBullets View PostAs a bullet designer that has done a lot of work personally pushing different calibers to their upper limits.
You cannot look at case capacity alone. You also have to look at available pressure.
Available pressure and time under the pressure curve is what makes bullets go faster.
Of course that speaking of internal ballistics and not including rifling profiles, engraving friction and bore lining.
Another thing that is seldom mentioned is the width of the shoulder and how it effects pressure when looking for maximum performance.
This is why Weatherby used the rounded shoulder they did. I am working with a long range bolt rifle company that has went to the Weatherby shoulder in a new cartridge they are designing due to less pressure spiking.
This is also one reason the 30 Herrett can push a 125 grain bullet 2791 FPS from an 18in barrel. Now granted it does not have the high BC you all love, however it does speak to what I am pointing out.
There is a new TAC6 coming out on the 6.8 case.
With the current support by Nosler and Federal on 6.8 case based cats it may be worth looking at.
I do not think pushing the 6mmAR shoulder forward such a small amount will gain what your looking for.
Seems like i should wait for a TAC6ii.Let's go Brandon!
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What about terminal ballistics? I see 6mm projectiles dominate PRS and other LR competitions, but are they useful for hunting medium sized game?
One of the nice things about Grendel is the immense body of data around the effectiveness of 6.5mm projectiles in harvesting game.
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6mm's have been harvesting medium sized game for years. Also allows for lighter loads for thin skinned animals. Light recoil, flat trajectory, etc... barrel life is its only major draw back. But if you're burning out barrels, cost of ammo exceeded the barrel and smith work roughly by 2x -3x's.
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Originally posted by CavityBackBullets View PostAs a bullet designer that has done a lot of work personally pushing different calibers to their upper limits.
You cannot look at case capacity alone. You also have to look at available pressure.
Available pressure and time under the pressure curve is what makes bullets go faster.
Of course that speaking of internal ballistics and not including rifling profiles, engraving friction and bore lining.
Another thing that is seldom mentioned is the width of the shoulder and how it effects pressure when looking for maximum performance.
This is why Weatherby used the rounded shoulder they did. I am working with a long range bolt rifle company that has went to the Weatherby shoulder in a new cartridge they are designing due to less pressure spiking.
This is also one reason the 30 Herrett can push a 125 grain bullet 2791 FPS from an 18in barrel. Now granted it does not have the high BC you all love, however it does speak to what I am pointing out.
There is a new TAC6 coming out on the 6.8 case.
With the current support by Nosler and Federal on 6.8 case based cats it may be worth looking at.
I do not think pushing the 6mmAR shoulder forward such a small amount will gain what your looking for.
The term you're looking for on the Weatherby design is called a "double radius".
The 6mm AR Turbo is used for this reason over the 6mm AR.
The shorter, fatter powder column in a Grendel or BR-type case will burn more efficiently than an early 1900's type 30 Remington-based case.
It's one of the reasons you see 6.5 Grendel at lower working pressure getting the same speeds as a 6.8 case with the same bullet weight pushed to higher pressures.
It makes no sense at all to use a lower capacity case with inferior shaping to it when we're trying to get more mv, especially with the lower bore volume of a 6mm.NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
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Originally posted by m796rider View PostWhat about terminal ballistics? I see 6mm projectiles dominate PRS and other LR competitions, but are they useful for hunting medium sized game?
One of the nice things about Grendel is the immense body of data around the effectiveness of 6.5mm projectiles in harvesting game.Originally posted by K_4c View Post6mm's have been harvesting medium sized game for years. Also allows for lighter loads for thin skinned animals. Light recoil, flat trajectory, etc... barrel life is its only major draw back. But if you're burning out barrels, cost of ammo exceeded the barrel and smith work roughly by 2x -3x's.
Larger 6mms (243win, 6mm rem) have higher velocity to compensate for the lighter bullet.
223s have been used to take thin skinned game as well but I don't think it is a good idea.
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