Combat Rifle Rd

smittyb

Well-Known
Nov 12, 2009
2,153
113
Cut N Shoot
There are a shit load of better choices.
6.5 Grendel, 25-45, 6x45, 277 Wolverine just for starters.

Now the best round, that is a debate that will not be settled on this forum, or any forum.
 

zackmars

Well-Known
Nov 4, 2015
1,661
113
Texas
Knockdown power or sometimes referred to as Killing Power, here is the formula.

E x SD x A = KPS

Energy (in foot pounds) x Sectional Density (taken from reloading manuals) x cross-sectional Area (in square inches) = Killing Power or Knockdown power call it whatever you chose.
If you are not happy with that then apply the formula for Kinetic Energy: kinetic energy (KE) is equal to half of an object's mass (1/2*m) multiplied by the velocity squared. For example, if a an object with a mass of 10 kg (m = 10 kg) is moving at a velocity of 5 meters per second (v = 5 m/s), the kinetic energy is equal to 125 Joules, or (1/2 * 10 kg) * 5 m/s2

Its just physics no more, no less, but what it does is provide an index(s) on which you can make some probable outcomes.

No, Deer don't shot back or wear armor, nor did I say they did. However the size of an average Whitetail Texas summer deer is about 150 lbs, their body size is about that of a full-grown man and like men they have organs, muscle and bone so the similarity if about equal and faer more accurate in testing than a gel block that contains no bones and has a uniform density vs muscle and organs.

Weight*: While a consideration, the Army has not figured out how to have a major impact on load-bearing combat weight. Of the 3 studies I am familiar with, Vietnam, Ft Lewis* and ME wars the COMBAT load has varied less than +/- 5 lbs from 147 lbs. The TO&E, on the other hand, varies a lot. Winter Vs Summer could swing from a low of 82 lbs to a high of 106 lbs, but that is NOT COMBAT loading that is just TO&E but does include your basic weapon and No Ammo.

* Weight between a AR10 vs AR15 dressed out same-same for Infantry or civilian is about 2 lbs in fact about 1.8 +/- oz's.

As for the frame, if you use the Win Short Mag .243 you get the same length as the 5.56, but it gains in the girth by being a fatter round. That will cost 5 rds or in a 30 rd mag 25 vs 30.

Yes, the Army is on a tear to get the weight down and seeing as that have not been very successful since WWII I don't see any magic on the horizon. Of course, this is being driven by the integration of women into the Infantry.

*Ft Lewis Study: one of the things looked at was the optimal carry weight. Sadly that did not give the Army and answer it wanted to hear so it was not disseminated. However, their office was the same building and down the hall...20% of body weight was considered the optimal load-bearing carry. To make it worse an Infantry soldier around 5'10" - 6' 2" and weighing about 175-200 lbs will lose approx 35-50 lbs in the combat role.

ANYHOW...point is there are a lot of superior rds to the 5.56 and I am more than a bit concerned since the Army has stated it is going to design its own rd...telling us that of all the COTS rds out there nothing is suitable...I find that hard to believe!

There is no such thing as knockdown power, killing power, whatever you want to call it.

It is not scientific, it is not measurable

It is, plain and simple, gun store BS.

Always has been, always will be.

The fact that no ballistics lab, or ballistician uses the term or your formula is a clue.


Caliber is not everything. You seem to really want something like .243wsm, yet you have failed to recognize the biggest issue is that it is not suitable for a select fire rifle. And as far as 6.5cm, it may be a suitable replacement for DMR's and LMG's, but the size and weight penalty going from 5.56 is huge.

Sure you may loose only 5 rounds a mag, but now either the stamdard AR platform takes a significant hit to durability and parts life (particularly barrels) or you waste time and money developing a complete replacement for the AR FOW, that despite its age, is still far superior to other competing options.

Lets say you adopt your preferred barrel burner, will the avg. Soldier/Marine be able, in a combat environment, be able to take advantage of the extra long range performance of the .243wsm?

Is that extra tiny edge worth the increased recoil, the decreased capacity, the increased weight and enormous cost of the new caliber? Because for each little thing a great shooter can take advantage of, an average to poor shooter will be hindered by
 

zackmars

Well-Known
Nov 4, 2015
1,661
113
Texas
The .243 WSM is a barrel burner. Even on a basic infantry weapon you're talking about swapping barrels quite often. In a combat situation you would need to issue barrels. That means the weapon needs to have a user swappable barrel. That's going to increase complexity, weight and cost.

Taking a look into the not so distant past, the second battle of Fallujah, some of those Marines would have needed to swap barrels at least once a day, if not twice.

Base diameter of the .243 WSM is almost half again that of the .223, I think your estimates of magazine capacity loss are a bit off.

People think quick swapping barrels, like the AUG has are cool, but you could easily cut off a pound off that gun if you got rid of that system. I was really interested in the F88 from Lithgow which did just that.

Unfortunately that guns DOA
 

Ole Cowboy

TGT Addict
May 23, 2013
4,048
113
17 Oaks Ranch
The .243 WSM is a barrel burner. Even on a basic infantry weapon you're talking about swapping barrels quite often. In a combat situation you would need to issue barrels. That means the weapon needs to have a user swappable barrel. That's going to increase complexity, weight and cost.

Taking a look into the not so distant past, the second battle of Fallujah, some of those Marines would have needed to swap barrels at least once a day, if not twice.

Base diameter of the .243 WSM is almost half again that of the .223, I think your estimates of magazine capacity loss are a bit off.
What exactly is it that burns out the barrel, I hear this term from time to time and am wondering what causes it?
 

zackmars

Well-Known
Nov 4, 2015
1,661
113
Texas
What exactly is it that burns out the barrel, I hear this term from time to time and am wondering what causes it?
Big case, small bullet.

Lots of pressure, gasses, and heat. This causes erosion at the throat, and particularly to gas operated guns, gas port erosion

If you take a .308, which has a pretty respectable barrel life, and neck it down to a .243 win, barrel life suffers.

In a bolt action rifle, it's not that noticeable, as it's not being shot a whole lot, and the action is inherently "slow", but when the gun has a much higher practical rate of fire...
 

Ole Cowboy

TGT Addict
May 23, 2013
4,048
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17 Oaks Ranch
Few here may be missing the point of the discussion. As we speak the Army is moving to a new caliber, the 5.56 is leaving the building. While they have not made a decision yet, they intend to sooner rather than later.

My number 1 point and were I on the board I would ask the question: Is there nothing that is out there now that cannot do the job we want, I just have a hard time with reinventing the wheel...that IMO should be our last choice. Because we drive the train and coming up with an all-new round will affect all services and NATO.

Functionality is key and right now emerging tactics are driving the train and forcing us into a new round. Tactics are calling for soldiers engaging out to 800m. I am just not sure that is doable at the individual soldier level, that is a high bar. Anyhow another discussion on tactics!
 

zackmars

Well-Known
Nov 4, 2015
1,661
113
Texas
Few here may be missing the point of the discussion. As we speak the Army is moving to a new caliber, the 5.56 is leaving the building. While they have not made a decision yet, they intend to sooner rather than later.

My number 1 point and were I on the board I would ask the question: Is there nothing that is out there now that cannot do the job we want, I just have a hard time with reinventing the wheel...that IMO should be our last choice. Because we drive the train and coming up with an all-new round will affect all services and NATO.

Functionality is key and right now emerging tactics are driving the train and forcing us into a new round. Tactics are calling for soldiers engaging out to 800m. I am just not sure that is doable at the individual soldier level, that is a high bar. Anyhow another discussion on tactics!
Do you know how many programs and billions of dollars have gone into replacing 5.56 and the ar15? SALVO, SPIW, G11, ACR, OICW, XM8, and a few humdred tests of the M16/M4 of varying degrees of legitimacy sprinkled in... And this has been going on since the 5.56 was adopted.

Don't hold your breath. While 5.56 isnt infallible and there is a chance it may get replaced, its far more likely that everyone once again realizes that its just a waste of money and the current system does 99% of the job at 1/10th the price.
 
Last edited:

easy rider

Texas Ice Age Survivor
TGT Supporter
Jun 10, 2015
25,721
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Odessa, Tx
Do you know how many programs and billions of dollars have gone into replacing 5.56 and the ar15? SALVO, SPIW, G11, ACR, OICW, XM8, and a few humdred tests of the M16/M4 of varying degrees of legitimacy sprinkled in... And this has been going on since the 5.56 was adopted.

Don't hold your breath. While 5.56 isnt infallible and there is a chance it may get replaced, its far more likely that everyone once again realizes that its just a waste of money and the current system does 99% of the job at 1/10th the price.
Then again, we're talking government, and I used to work for the DoD.
 

avvidclif

Sturgis '95, RFTW 2010
TGT Supporter
Aug 30, 2017
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Van Zandt County
My thoughts. And I'm sure I will get corrected if needed. If a bullet has xxx ft lbs of energy(plain physics) and hits an object but does not exit then the object absorbs all xxx ft lbs of energy. I'm not discussing damage or anything else but say 1000ft lbs of energy is absorbed in a body something is going to get hurt.
 

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