.300 vs 6.8 vs 7.62x40

[iMagUdspEllr]

@GannutAF: I just found out that Barret makes 30 round magazines for the 6.8 SPC. So, actually, that simplifies things a lot. Now, the question is if 16" barrels are fine or if a shorter rifle would actually give some tangible benefits.

[iMagUdspEllr]

@Arctic1: I do like the different perspective. But, if we take into the account the average skill level of shooters... then a round that is capable of longer range hits has less value... because the user wouldn't be able to do it anyway. Also, isn't it normal to call in some sort of air support if the enemy is really far away (>300m)? I don't know, I'm just asking.

Yeah, it's a miracle we have won a single firefight with flawed ammunition.

There is a difference between flawed and horrible. Don't be too dramatic.

Are you seriously calling a 5.56 a pistol caliber carbine/round?

No, I was redefining the objective of an intermediate rifle round (which the 5.56x45 DEFINITELY is). I was redefining the purpose of an intermediate rifle round to make the objective of selecting one of these OTHER rounds over the intermediate round we are CURRENTLY using.

Again, I have seen many times in my 10 years of service, keyholing 7.62 hits in targets after shooting through light brush. Same with 5.56 of course.

Okay. I don't understand why people brag about the 7.62x39's ability to navigate brush better than the 5.56x45 then.

You were talking about shooting through light brush, not plates.

Obviously we need the bullet to do something to the target after it navigates the brush (I already specified that this is for military applications). Your train of thought doesn't make sense to me. I don't understand why its relevant to the discussion to not consider how well it performs against the target after punching through the brush.

But unless I get a rifle/carbine/LMG in a caliber that has a better effect on target than my 7.62 GPMG, my M2 .50 cal browning, my 40mm underlsung or GMG, my M72's or my 84mm HE I am not going to be concerned about the current rifle caliber.

Those weapons are not meant to have light infantry as their primary target. And, if they do, they are primarily used for suppression. But, this is WAY off topic because...

For the role you are describing, engaging targets out to 300 meters, the current platform is sufficient.

Sufficient =/= best/ideal.

[Arctic1]

If you do not have military experience, it is sort of pointless to argue a hypothetical capacity gap/ineffieciency, when you do not know how we (mil) employ weapons systems, and the tactics we use.

Also, isn't it normal to call in some sort of air support if the enemy is really far away (>300m)? I don't know, I'm just asking.

Those weapons are not meant to have light infantry as their primary target. And, if they do, they are primarily used for suppression.

These comments sort of sum it up.

I could give a quick run down of for example a deliberate attack, but it is probably waaay off topic.

Read this discussion:

http://m4carbine.net/showthread.php?t=95449

[az doug]

did you read the article I posted in my first reply?

That article explains exactly what you are asking about...

it discusses Intermediate Calibers exactly and shows that for an intermediate caliber, as in below 500 meters, that 6.8 is the optimal solution....

MistWolf already covered the definition of "intermediate" cartridge so I will respond to the article you linked.

I did read the article you linked and enjoyed the read, however, the criteria the OP established is different than the article. The OP wants a 300 yard or meter cartridge (I forget which and I am not going back to look) and the article's criteria lists a 500 meter cartridge. What may have been a superior cartridge out to 300 could be eliminated if you add another 200 to the criteria.

I have owned a 6.8 for years and recently built a 12" 300 blk. (I also own a .308 wn AR) I am still testing the 300 blk but if it performs as advertised to 250 yards then it fulfills my needs of a patrol rifle better than the 6.8. or 5.56. 250 yards is the criteria I established for myself, but the reality is it will be used at less than 60 yards and more realistically pistol distances. That is just the reality of my world.

Other reasons I like the 300 blk: Interchangeability of parts, including magazines. (only the barrel is different) I can form my own brass and I can shoot it subsonic in our local subgun match. (a plus for me) There are other reasons, but those are the main ones for me.

A 110 gr 300 blk traveling at 2150 fps zeroed at 225 yards will be 5.52 inches above LOS at 125 yards and 3.51 below at 250. (Those are the highest above and lowest below LOS for a 225 yard zero) For me those are workable figures. I am still working on the optimum zero for my purposes, but that one is not bad.

[Reagans Rascals]

Reagans Rascals
Boy you sure have a case of the ass for the 300 Blk don't you!!! Maybe you need to shoot one so you can lighten up Franses.

I have a 300 Blackout and reload my own ammo, with a Form 1 Suppressor I made myself for it... I love the round... I use it for my HD gun every single day and night... so I have no idea what you are talking about

[iMagUdspEllr]

Well, I am currently in the Air Force and I have been in for almost 5 years now. But, that is why it is painfully obvious that I know nothing about combat (I just fix planes).

But, yeah, this is sorta starting to get off topic.

I'm still asking why wouldn't we use the best/ideal caliber/platform if its out there?

[Reagans Rascals]

Well, I am currently in the Air Force and I have been in for almost 5 years now. But, that is why it is painfully obvious that I know nothing about combat (I just fix planes).

But, yeah, this is sorta starting to get off topic.

I'm still asking why wouldn't we use the best/ideal caliber/platform if its out there?

Because "best out there" is situational dependent... there are a host of different platforms and different calibers all for different missions and situations. 5.56 does well for most of those

and the reason our military doesn't use the best platform or caliber out there.... is because huge organizations like them are very slow to change... and are tight when it comes to spending money on new weapons for fielding... notice how the SCAR was only fielded with SOCOM units because they have the funding to hold new weapons trials... and when was the last time they held trials for and accepted a new caliber of ammunition?

I'm more than sure the MP7 would be the ideal CQB weapon to hand out to every single sailor, soldier, and Marine.... but Devgru is the only unit in the US to use them....

[lunchbox]

Went with 6.8 (it makes things pop) just a country boy that likes to shoot, don't need SBR, don't need silencer, nor the hassels/expenses. Just want a gun to play with and that will drop white tail 100lbs (doe) through 200lbs and hogs. Do like my buddies 300 (it also makes things pop) its just not for me.
I think 6.8 vs 300 is like Blondes vs Brunettes, it depends on what kind of freak ya are

[iMagUdspEllr]

@Reagans Rascals: Yes, but I did define the situation (intermediate rifle caliber).

This sticky: http://m4carbine.net/showthread.php?t=19913

That kinda makes me lose my confidence in the P90 and MP7. I would rather use something that hits with more energy than a pistol caliber. But, that is off-topic.

Since 6.8 SPC and .300 BLK have the same magazine capacity now... do you think that it would be a good idea to have a sub 16" barrel? Because at this point the 6.8 SPC is the clear winner unless there is a tangible benefit to reducing the overall length of the rifle (that outweighs the range/energy benefits of the 6.8).

[fdxpilot]

Right, but if you lose 5 rounds in magazine capacity for about a 500 ft-lb increase in energy......


The 6.8 gets the most jump in energy of the three but it suffers a loss of 5 rounds of capacity. As soon as you start losing magazine capacity you are straying away from the point of intermediate rifle rounds.

You do know that Barrett makes 30rd 6.8SPC mags, don't you?


Sorry, didn't read far enough down the page.