AR10 in 243 Win....why so few?

[Hookeye]

4350 in .243 w 70gr Nosler BT is wicked chuck medicine.
And has some blast from a 22" bbl.
Shorter gets more annoying.

 

[MachIVshooter]

It's funny you seam to recognize that the larger case in the shorter barrel does the same thing and seam to recognize the advantage of a shorter barrel, you even seam to grasp the use of a smaller lighter bullet for some purpose. But then turn around and say well none of that really exists because and I quote "drop can be accounted for"
Way to be totally dismissive of THE ADVANTAGE.

but I gotta ask why have a 25-06 if you can just account for drop?

Try reading the post again. And look at my subsequent one explaining powder charge to bore area ratios.

I didn't say overbore small caliber rounds don't have advantages. I said those advantages evaporate when you neuter them with a barrel too short to attain the velocities that make them advantageous in the first place.

I like the velocity & trajectory of my .25-06. If I take 6 inches off the barrel, it's greatest attribute is no more. Meanwhile, the .30-06 it's based on, and especially the lower ratio critters on the other end like .338-06 and .35 Whelen, suffer far less velocity loss with the same barrel chop.

Your 6 Creed from a 16" barrel will do no better than the smaller 6BR in the same tube.

 

[MachIVshooter]

An 18" SPRish 7mm-08 build would be sweet

7mm-08 is one of those rounds that should be more popular than it is. It's got enough bore area to do well in shorter barrels, yet is able to take advantage of higher BC, higher SD bullets than its parent cartridge in most rifles. Definitely hits a sweet spot. That's why the integrally suppressed build I just did as a demo is 7mm-08. Well, that, and just to be different.

 

[Varminterror]

Your 6 Creed from a 16" barrel will do no better than the smaller 6BR in the same tube.

This is the same silliness that folks spread around about short barreled magnum revolvers. It’s just not true to claim these things - the 6 creed will remain faster than a 6 BR in a short barrel. Not as much faster, and yes, it will have a much louder blast, but it DOES remain faster. I tend to expect you’d know better and have experienced more than to make false claims like this.

Running short barrels might not be worth it to YOU, but the speed advantage for larger and faster cartridges over smaller and slower cartridges does remain in short barrels.

 

[mavracer]

Your 6 Creed from a 16" barrel will do no better than the smaller 6BR in the same tube.

I also seriously doubt that is true, but I'm not cutting my barrel to see. I can say without a doubt that my 20" 6 Creed is as fast as the guys running 27 and 28" BRAs and Dashers.

 

[MachIVshooter]

This is the same silliness that folks spread around about short barreled magnum revolvers.

Magnum pistol rounds also suffer considerably in short barrels. I have 3", 4" and 6" .44 magnums (and a 20" 1894 carbine, but that's not material to this discussion), and there's a big difference. I don't have my load data records in front of me right now to give exact readings and averages with the various loads, but the sledgehammer 240 gr. loads out of the 3" 629-2 were actually lower energy than 180 gr. 10mm loads from a 5" semi auto. A .44 mag loses about 300 FPS going from 6" to 3". That's a huge drop when you were only running 1,300-1,400 out of the 6" gun. Also have 2", 4", and 6" .357 magnums, as well as carbines, have had 3 and 8 inchers in the past; .357 mag suffers even more. If you don't like my figures, go check out BBTI.

No, .357 out of a 3" barrel doesn't drop down to .38 spl levels as some have suggested at other times. But it's also running at twice the chamber pressure. That's not the case when comparing 55-60KSI rifle rounds. I'm not and never have suggested the .22-250 becomes a Hornet in a short barrel, but I am saying with absolute certainty that it suffers much greater velocity loss in a shorter barrel than a more efficient round like the .223, and there is a point that the extra powder turns almost entirely into muzzle blast instead of velocity. At 18", .223 gets within 100 FPS of the .22-250. At 14", your shot to shot variation is likely to be more than the average difference between the rounds.

.243 will lose 250-300 FPS going from a 22" gun to a 16" gun. .308, OTOH, loses about 150 FPS average with the same 6" chop. That doesn't mean a 16" .243 is ineffective or useless, but it does mean that it suffers quite a bit more, and that's the point I've been trying to get across.

This stuff is not speculative. It's material fact, and has been tested by far more people than myself. I also personally own weapons in many of these chamberings, and would wager that I've done more with barrels of different lengths in them than just about anyone on here, save for Clark. I have a .243 that we cut, have built and shortened others. I have done 6.5 CM builds & chops from 12" to 26". .223 from 7" to 24". .22-250 from 20 to 26". .308 from 8.5 to 28". .30-06 from 18-27". .300 win from 18" to 26".

I also seriously doubt that is true, but I'm not cutting my barrel to see. I can say without a doubt that my 20" 6 Creed is as fast as the guys running 27 and 28" BRAs and Dashers.

You're talking about what is really the minimum practical length for .243/6 creed vs. quite long barrels for the stubby benchrest rounds that offer rather little velocity advantage over a 20" or 22". And none of those are the lengths we were discussing as handicapping overbore rounds. 6BR and 6 Dasher behave more like .308 win, gaining or losing only 30 ish FPS per inch in the 18-26" range. Above 26", they gain very little, down to single digit by the time you're approaching 30".

As well, the 6 creed from a 24" gun has a 300 FPS advantage over the 6 BR in the same 24" tube. So yeah, losing 150-200 FPS going down to 20" with the Creed vs. gaining only 20-25 FPS per inch from 24" to 27" or 28" with the BR or dasher, the math works out just fine. Point remains that the BR or Dasher will suffer less velocity loss going down to 20" because they are more efficient cartridges. I feel that you are being willfully obtuse about this and creating deliberately flawed arguments to support an untenable assertion. You're also being rather hostile in your replies; I will not continue this discourse if you cannot be dispassionate and objective. We're discussing cartridge ballistics here, not politics or morals. We all like what we like, but being disingenuous due to your preferences doesn't bolster an argument.

Now, one more time, the powder charge to bore area ratio has a direct correlation to the velocity gain/loss with different barrel lengths. The effects are more profound as you move further from the ideal barrel length in either direction, and the lower that ratio, the shorter that "ideal" barrel length (best balance between portability & performance) can be. And that brings us back to the thread topic of why the .243 isn't very poplular in ARs, which a LFAR gets rather unweildy for most of its purposes with barrels over 20". 18" barrels on a LFAR give an OAL about the same as a 22"-24" bolt gun, which is why it's such a popular length. The more dramatic velocity loss of the .243 vs. .308 in that shorter barrel is one of the reasons it's not a popular choice. Ammo price and availability are a larger factor, but the contribution of external ballistics should not be ignored.

 

[Varminterror]

You’re finally espousing truth:

Paraphrasing: Higher over bore capacity cartridges lose more than lower ratio cartridges.

But this remains false - and it IS what you claimed, which is why I called it out as such:

Your 6 Creed from a 16" barrel will do no better than the smaller 6BR in the same tube.

Taking too much liberty with a generalization like that is lost on folks unfamiliar with the subject matter, and especially those who recognize your knowledge here. So the above statement is blatantly misleading.

It’s true to say a 308win loses more velocity per inch than a 338 Federal, but it’s not apt to say a 10” 30-30 performs equal to a 10” 308win because the 308win has higher case:bore ratio. Just as it’s true to say a 243win or 6 creed lose proportionately more in a shorter barrel than a 308win, but it’s just NOT true - as you claimed - to say the 6 creed does no better in a 16” better than a 6BR.

In this case, mean what you say, or say what you mean, because the folks your advising might not realize when you’re being so frivolously hyperbolic.

 

[Varminterror]

I knew a bunch of guys in the early 2000’s, then a dozen or so more in the boom of ~2010 which used 243win LFAR’s for coyotes, selectively. I built several of them upon request, including my own. The shift after Sandy Hook to rejuvenate the AR-15 market, and the natural ebb of the coyote calling boom saw a virtual end to that market. The weight of the LFAR was the major draw back. The specific type of coyote caller, even 20yrs ago, who favored the larger 243win over the 223/5.56 or 22-250 also tended towards svelte bolt guns. These were typically the guys calling over larger territories with less cover, making longer walks and taking longer shots where the 243win became distinctly advantaged over the 22cf’s. Such the market for LFAR 243’s for coyote hunters were a unique blend of territory where guys expected multiple shot opportunities and had room to make them, but either didn’t have the long walks where weight hurt as much, or fancied themselves strong and fit enough to bear the extra weight.

There’s also a lingering market stigma that 243win’s are “youth or women’s rifles, unbecoming for a big, strong man.” But conversely, LFAR’s are heavy, and decidedly not ideal for smaller or weaker hunters (aka, women and youths). So there’s a happy market for 20” 243win bolt guns to enjoy, but the 243 LFAR’s lag in the same market.

Today, honestly I think the AR-10/LFAR has proportionately fewer fans than any time in recent decades. The industry has brought forth multiple AR-15 length cartridges which maximize the performance of the frame, which has largely negated the advantage of the LFAR for most potential users. We have more options than ever in both platforms, but the AR-15 market remains climbing and the LFAR market is (disappointingly) waning...

I also point to the fact the 6.5 creed has pushed the 243win LFAR market aside, AND frankly, it’s easy to observe the fact the 6 creed has confused the 243win market, especially the 243win LFAR market - as small and fragile as it already was. The 243win has been well recommended for generations, but the 6 creed has the stigma of poor barrel life (unknown to be better than the 243win by the folks formerly recommending it), but observed better performance with heavier bullets... so the less experienced would-be buyer suffers analysis paralysis and doesn’t buy either...

Lots of moving parts...

 

[Hookeye]

Chopping a barrel may make some cartridges less efficient compared to others.
That doesn't mean a performance gain over the others doesn't exist.
Its just another "how much do you want to pay for it".

Personally, I dislike blast, crack and recoil more and more the older I get.
Hot stuff short annoys me.
But with silencers becoming more common, a short bbl may still have decent handling with such (not be too long) and maybe benefits more worthwhile.

 

[Hookeye]

I dunno as I have not played that game.
But have an open mind.
Since I like classic stuff, am not an AR fan....do like the .243 win cartridge.....
I'll stick to 22 and longer bbls, on rifles of action length.
I did NOT like the blast off my #1 RSI (no real action length and 20" bbl).
It was noticeable when shooting a deer.
First time ever with a long gun deer hunting I felt it and went "what the heck?".
S s s s s sold it.

 

[MachIVshooter]

Taking too much liberty with a generalization like that is lost on folks unfamiliar with the subject matter, and especially those who recognize your knowledge here. So the above statement is blatantly misleading.

If we consider the starting velocities and the loss rates for each cartridge, "frivolous hyperbole" is not an accurate statement either. It's an inflammatory one.

I didn't post any exact figures, as there is a general lack of published data for short 6BR or 6 Dasher barrels, and too many variables in play with internal and external ballistics to state that "at this exact length, the velocities will be identical". That's especially true with the bullets and powders typically used in the handload-only specialized stubby critters, shooters often using rather slow powders in long barrels to maximize the round's potential versus optimizing for short tubes. .243 loads are overwhelmingly optimized for 22"-24" barrels, not 27"-32".

What we do know is that cartridges which lose proportionately more velocity at an increasing ratio with shorter barrels will eventually reach the point where they do not outperform a slightly smaller and more efficient round. Maybe it's at 14.5" and not 16" for the aformentioned. Again, hard to speak in absolute figures for several reasons. But with the .243/6 creed losing about 50% more velocity per inch under 24", there is a point when that initial 250-300 FPS advantage is gone. In practical use, once they're within about 100 FPS of each other, you're there. Ergo, if the 6 Creed is down to 2,500 FPS with a 100 gr bullet in a 16" barrel and the 6 BR or Dasher is achieving somewhere around 2,400, I maintain that it's really not doing any better.

ETA:

Just to clarify for the onlookers asserted to not understand what I'm saying here, when speaking in practical use terms, I don't nitpick 5% velocity differences between two rounds, just as I don't get hung up on tiny differences of a couple dB with suppressor SPL reduction, 6 ounces between two different hunting rifles mattering in the field, or assert that a big block Mopar with 665 HP will make a quicker car than a big block Chevy with 640 HP, or that a 9,500 lb winch is able to outperform a 9,000 in any meaningful way, etc. That may seem odd for someone who deals with very precise numbers every single day dimensioning & manufacturing parts, but it's a matter of what's appropriate and understanding how to apply variables, tolerances, margins in the real world. Minuscule numbers can make a big difference in one application, while much larger disparities don't count for beans in another. I indicate a bore for threading to <.0005" TIR, but I certainly don't apply that level of precision when I cut a 2x4. Being pedantic about the smallest of details that are totally inconsequential I leave for the marketing guys.

 

[Varminterror]

I can say for 243win, 6BR, and 6 creed, this imaginary convergence point you’ve proposed is shorter than 10”.

 

[MachIVshooter]

I can say for 243win, 6BR, and 6 creed, this imaginary convergence point you’ve proposed is shorter than 10”.

I would say longer than that with both rounds optimized for short barrels, but I don't think either one of us has the time or capital to buy the weapons, dies, brass, bullets & powder to test a couple dozen different loads to establish that exact point. And in the end, it would be purely academic to do so.

Admittedly, I have a reason for disregarding small velocity differences between efficient and overbore cartridges beyond the average shooter, and that does factor into my opinions on the matter. I cut a lot of rifles to the shortest practical length and suppress them. For this reason, there is zero appeal to using something like the 7mm Rem Mag over the 7mm-08 for the integral when all that extra powder adds up to rather little velocity advantage in an 18" barrel that's ported from 14.5" and makes it that much more difficult to suppress with all the extra gas volume and all the powder that's still burning through the can. So yes, I will gladly sacrifice 50 or 100 FPS, perhaps more, to gain several dB reduction, especially when the practical use of the weapon makes the disparity immaterial.

 

[Varminterror]

While I don’t have all 3 today to make the test simple, I specifically mention these three because I own or have owned 10” specialty pistols in these 3 cartridges, and have done the load development... theory need not apply, btdt. Don’t forget, there are a whole lot of us specialty pistol fans out there actually doing this, not just theorizing and exaggerating on forums.

 

[mavracer]

Just to clarify for the onlookers asserted to not understand what I'm saying here, when speaking in practical use terms, I don't nitpick 5% velocity differences between two rounds

Well just to clarify for the onlookers that more than understand about cartridge efficiency and the effects barrel length has on velocity.
My 20" 6 Creedmoor loses less than your 5% threshold for nitpicking from my 24" Ruger Precision.

 

[MachIVshooter]

Well just to clarify for the onlookers that more than understand about cartridge efficiency and the effects barrel length has on velocity.
My 20" 6 Creedmoor loses less than your 5% threshold for nitpicking from my 24" Ruger Precision.

It's right there, but again, it's practical application. I don't suddenly decide that it's unacceptable at 5.1%, or that every barrel should be shortened as long as the loss is less than that. My 220 Swift is 26", and given the purpose of that round and the host it's in, I didn't shorten it at all and don't plan to. I use slower powders to squeeze every last bit out of it for the flattest possible trajectory and shortest possible TOF on praire dog towns where shots are often in excess of 500 yards.

On the flip side, as I explained once already, when it comes to a weapon that needs to have a short barrel, I evaluate it's purpose and choose the most appropriate round. .280 AI is a cartridge I have a particular fondness for and which has a decided advantage over the 7mm-08 in a 24" or 26" barrel. Where the integrally suppressed rifle was concerned, though, having an 18" barrel with porting from 14.5 that effectively makes it a 15-16" tube, the .280 AI has almost no velocity over the smaller, more efficient 7mm-08, just more powder burning outside the barrel.

I don't know why you're so hung up on arguing for the 20", though, which I never said was a severe handicap for the .243/6 Creed. It's a strawman argument. I did, however, say that's about as short as you want to go, because when you start getting below that, 18, 16, shorter, the loss is far more dramatic. The 24"-20" chop is going to cost you around 120-150 FPS, Fairly negligible with a round that's starting out near 3,000. Another 2" to 18" is another 100+ FPS, though. 18" down to 16", another hundred and change. And the loss will continue to increase more profoundly with every reduction. Each inch or two may be less than ~5%, but we're not doing convoluted government COVID math here, so we look at the aggregate, and 350 FPS is most definitely significant for any small arms cartridge, even the fastest ones. After all, that's more than the velocity advantage your 6 Creed had over the short critters in ~24" barrels that made you choose it to begin with, right?

Again, don't take my word for it

https://rifleshooter.com/2016/04/243-winchester-effect-of-barrel-length-on-velocity/

 

[mavracer]

I don't know why you're so hung up on arguing for the 20", though, which I never said was a severe handicap for the .243/6 Creed.

All the advantages of the high velocity small bores are lost when you start getting shorter than 22".

??????????????????????????
And the reason is I agree a 14-15# 24" bull barrel AR10 is a pig compared to a 20" H bar and I'm thankful I didn't buy in to your theory that 243/6 Creed gives up too much shorter than 22.

 

[MachIVshooter]

??????????????????????????

Ignoring for the moment that we have two related but different subjects here, let's talk about your puzzlement and the meanings of words:

Advantage lost: No longer better (than something else)

Severe handicap: Much poorer performance (than what it had)

A gifted person has an advantage over the average person. A severely handicapped person has a decided disadvantage compared to the average person.

Make sense?

 

[mavracer]

So the advantage lost isn't due to the handicap of a shorter barrel?
Wouldn't it just be easier to admit you misspoke?