7x57 or 270 or 243?

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Same case loaded to the same pressure —> larger bullet exposed to same pressure = greater total force. Force = area * pressure. If pressure is the same, but area increased, the Force increases. Also, Force = M*A, so given the same M for an increased Force, then A must increase... Greater acceleration = greater muzzle velocity.

Naturally, we have a pretty simple geometric comparison of dimensions. Same bullet weight in a larger caliber is shorter, so when seated to the same length, we have more room in the case. That means we can fit more powder into the case under the same max pressure - powder is potential energy, so again, we have greater opportunity to convert to greater kinetic energy...

Pretty standard fare.

Such the only downsides in increasing caliber for a given cartridge case without increasing bullet weight are the decreases in ballistic coefficient and sectional density (related).

In short range, lighter, faster bullets might look great, but in the long range, speed simply can’t outrun aerodynamics.
 
One of my handloads using 130 Hornady GMX at 3,200 fps is tagged on the buttstock of my 24" barreled .270 Win, using chronographed handload performance.
Vel 3,200 fps chronographed in that rifle
Trajectory 100 yards +2.4 in
200 +2.3
250 +0.6
300 -2.3"
350 -6.6"
400 -12.3" My personal limit at our woods road blind. Hold...just a couple of inches over the deer's shoulder.
450 -19.6"
500 -28.6"
---------------------------------------
There may be better loads for some folks, but these measurements are real for my rifle and performance on several deer testify to its validity.
I may not use GMX bullets this year, but haven't made a final decision. This load has killed about 7 deer for 3 hunters, so far..all one-shot kills out to about 375 yards. Having mostly low pine trees on both sides of the old town road/now woods road/former snowmobile trail. It's dead straight and gated at about 500 yards.
 
LoL. The arguments over an inch or two at 400 yards....

The OP specifically asked about 243, 7x57, and 243. I don't really understand why those are the 3 he's deciding between, but I assume he has his reasons. I would say it really should depend on what he wants to do with it, whether he's going to load for it, etc.

The whole 270 - 30-06 thing is such a rare debate. <----- Massive sarcasm in case you didn't pick up on it.

They are the same thing. 270 is necked down 30-06 as I assume most of you know. Same pressure, etc. Do you want a little more frontal area or a little lighter bullet for the ballistic coefficient. Both of them have dropped more game than all of us can count and you won't go wrong with either one.
 
Get the 7X57 for sure, the .270 is about as exciting as false teeth at a retirement home and the .243 about the same. But when you get the 7X57 don't call it that, and only refer to it as your .275 Rigby (came caliber) It will make your hunting pals jealous. Especially when you tell them W.D.M (Karamojo) Bell killed upward of a thousand elephant with his .275 Rigby. Be sure to buy one or two of Bells books for more stories about his hunts. Here is a 7X57, Er .275 Rigby made by Al Bieson I've taken to Africa several times and it has worked fine for all game I've used it on (No elephants with it though) DSC_0284.JPG DSC_0290.JPG DSC_0295.JPG
 
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el Godfather said:
Hi
As a hunting rifle (bolt action 5 shot) which caliber would you prefer that you can also use on the farm (HD/Target/Plinking).

I personally lean towards the much under appreciated 7x57 Mauser. I find its recoil very smooth. I use an old Zastava made in Yugoslavia that has been kept by my father in a very good shape- good as new.

I also have a 243 by BRNO which is good caliber but the action on BRNO is stiff and not smooth. The caliber however is excellent flat shooting that takes care of all hunting needs if distance is adjusted for the game, BUT 7x57, in my opinion, does a better job. I believe even historically 7x57 has taken big game more than any other rifle.

That said, 270 always seemed to me as a weak 308 or 30-06. For it does the job not significantly better than 243 and may be about the same as 7x57 or perhaps slightly weaker. Thus, if I wanted something more powerful I would consider 308/30-06/7mag etc.

Your thoughts?
Click to expand...

Well...

If you don't need more than the .243 and you can put the work where it needs to be?

Step up would be the 6.5 CM or the grandpappy 6.5x55 Swede.

7x57, or its modern equivalent 7mm-08, puts you solidly into the "Big Game" class.

The .270 WCF seems to be misunderstood by many.

Loaded w/ 130 gr., it is a string straight, point'n'shoot 350 yard deer and antelope round.

The 150 gr. offerings, especially the Nosler Partition, drops that string to 300 yards, and adds thick bodied deer and elk to the menu.

It's been called a "crappy" .30-06, and in a way that may be true, especially when comparing heavy for caliber bullets in close.

But other than that - the .270/150 gr. shines.

Higher pressure, it is essentially a belt-less magnum of sorts.

The 150 gr. bullet has the SD and BC of the 180 gr. .30-06, but will push it at a coupla hundred fps faster, faster even than the 150 gr. .30-06.

So it flies flat, retains energy well, and penetrates like the 180 gr. .30-06 - with essentially the recoil of the 150 gr. .30-06.

Me?

I shoot the .270/150 gr. considerably better, and all day long at the range - than the .30-06/180 gr.

Not "blasting", but precision shooting, from field positions.

YMMV.

But you put the .270 WCF at the Top of your power list.

Something to consider.




GR
 
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Varminterror said:
Same case loaded to the same pressure —> larger bullet exposed to same pressure = greater total force. Force = area * pressure. If pressure is the same, but area increased, the Force increases. Also, Force = M*A, so given the same M for an increased Force, then A must increase... Greater acceleration = greater muzzle velocity.

Naturally, we have a pretty simple geometric comparison of dimensions. Same bullet weight in a larger caliber is shorter, so when seated to the same length, we have more room in the case. That means we can fit more powder into the case under the same max pressure - powder is potential energy, so again, we have greater opportunity to convert to greater kinetic energy...

Pretty standard fare.

Such the only downsides in increasing caliber for a given cartridge case without increasing bullet weight are the decreases in ballistic coefficient and sectional density (related).

In short range, lighter, faster bullets might look great, but in the long range, speed simply can’t outrun aerodynamics.
Click to expand...
max pressure for the 270 win is 52,000 cup, for the 30-06 is 50,000 cup. same power regardless, imo.

murf
 
Had my 7x57ai out today, for a few shots testing my reamer job on the neck. All went good and if it were a 270 don't think I'd enjoy it as much. The rifles important to me, it was built for me when I was a kid. By the little know gunsmith John van patten, he was p.o.Ackleys shop Forman and worked with him in the collage to. John made many of ackleys chamber reamers to. This was his last rifle, he died only a month or so after he have me the rifle, he was 83 if I remember right.

IMG_20200323_153748.jpg
 
murf said:
i don't think so. varminterror will understand that the two force differences will just about cancel each other out.

murf
Click to expand...

I actually threw the 270 a bone by NOT pointing out the gross force advantage for the 30-06, and offering parity.

I recognize I’ve only handled one piezo barrel, never owned one, and subsequently none of my equipment I’ve ever used to develop my hunting, plinking, or competition ammunition could ever tell the difference between 50 and 52kpsi. Alternatively, given nearly the same case fired from identical rifles, there’s no reason to expect any observable difference between the pressure indications yielded to the shooter which reflects one at 50, the other at 52. Primers will flatten and bolts will stick at the same standard, with no real connection to what is measured in a test apparatus somewhere else at some other time with some other lot of ammunition or brass.

Recognizing the same barrels and actions, same primers and similar brass are used for - let’s pick one - say 308win, operating at 62kpsi, we can only really speculate that we’re somewhere below 70kpsi, but have no indication if we’re even within 10kpsi.

But even if we did pretend we really had resolution down to 4% in our handloads, then the difference is simple - a 30 cal bullet has more than 23% greater cross-section than a .277”, while 52kpsi is only 4% greater than 50kpsi. In the simplified solution of F1=P1*A1 vs. F2=P2*A2, knowing that relationship, scaling bullet down 23.6% and pressure up by 4%, we have a gross force reduction at the peak pressure of more than 17% in the 270, lagging the 30-06. Not really “just about” cancelling out. But the thought exercise is always fun.
 
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el Godfather said:
Hi
As a hunting rifle (bolt action 5 shot) which caliber would you prefer that you can also use on the farm (HD/Target/Plinking).

I personally lean towards the much under appreciated 7x57 Mauser. I find its recoil very smooth. I use an old Zastava made in Yugoslavia that has been kept by my father in a very good shape- good as new.

I also have a 243 by BRNO which is good caliber but the action on BRNO is stiff and not smooth. The caliber however is excellent flat shooting that takes care of all hunting needs if distance is adjusted for the game, BUT 7x57, in my opinion, does a better job. I believe even historically 7x57 has taken big game more than any other rifle.

That said, 270 always seemed to me as a weak 308 or 30-06. For it does the job not significantly better than 243 and may be about the same as 7x57 or perhaps slightly weaker. Thus, if I wanted something more powerful I would consider 308/30-06/7mag etc.

Your thoughts?
Click to expand...


All three are great. But, if you like the 7x57, you will faint over the 6.5x55. That is the single most underappreciated, unknown cartridge in American. it's a LONG bullet, having unbelievable sectional density. It's like shooting a needle. Retains velocity and energy over a long distance, but the ballistics don't even show what a great round it is. JMO, it is worth a look for any antlered game, and for targets.
 
First up you guys need to move into the 21st century and use SAAMI transducer pressures not CUP. Yes both cartridges are older than most of us but using modern measurements where possible is probably better and more accurate. SAAMI MAP using transducer measurements is 60,000 psi for 30-06 and 65,000 psi for 270 Win. This brings 270 Win pressure advantage to ~8.3%

Next we can't stop at peak force we need to get to acceleration since velocity is ultimately what we are after and we need take into account the mass of the projectiles.

For a fair comparison I would suggest we should use two bullet that are exact copies of each other just scaled (up/down) from the other to the appropriate caliber. ie the proportions and features would be the same. If we accept this assumptions of exact scaling of the projectiles then a 180gr 30-06 bullet using classic scaling (ratios of the characteristic length cubed) would weight 130.9gr if scaled down to .277. Sort of freaky there ain't it. :D

Using these weights we would find that the peak acceleration for 30-06 is 5.59x10^6 ft/sec^2 where 270 Win is 6.74x10^6 ft/sec^2. So 270 Win has a 20% peak acceleration (at peak pressure). This advantage stays the same as long as the bullets are scales of each other. 220gr 30-06 = 160gr 270 Win, a 150gr 30-06 = 109 gr 270 Win etc.

For the same pressure behind each bullet 270 Win would have an 11% acceleration advantage over 30-06 when using projectiles of the same proportion with respect to caliber. Mass goes with the cube of the caliber were force is only going with the square of the caliber.

30-06 270 Win​
MAP: 60000, 65000
diameter: 0.308, 0.277
area: 0.074506, 0.060263
force: 4470.361, 3917.083
Mass: 180, 130.9362
Acceleration: 5.59E+06, 6.74E+06

:D
 
mcb said:
First up you guys need to move into the 21st century and use SAAMI transducer pressures not CUP. Yes both cartridges are older than most of us but using modern measurements where possible is probably better and more accurate. SAAMI MAP using transducer measurements is 60,000 psi for 30-06 and 65,000 psi for 270 Win. This brings 270 Win pressure advantage to ~8.3%

Next we can't stop at peak force we need to get to acceleration since velocity is ultimately what we are after and we need take into account the mass of the projectiles.

For a fair comparison I would suggest we should use two bullet that are exact copies of each other just scaled (up/down) from the other to the appropriate caliber. ie the proportions and features would be the same. If we accept this assumptions of exact scaling of the projectiles then a 180gr 30-06 bullet using classic scaling (ratios of the characteristic length cubed) would weight 130.9gr if scaled down to .277. Sort of freaky there ain't it. :D

Using these weights we would find that the peak acceleration for 30-06 is 5.59x10^6 ft/sec^2 where 270 Win is 6.74x10^6 ft/sec^2. So 270 Win has a 20% peak acceleration (at peak pressure). This advantage stays the same as long as the bullets are scales of each other. 220gr 30-06 = 160gr 270 Win, a 150gr 30-06 = 109 gr 270 Win etc.

For the same pressure behind each bullet 270 Win would have an 11% acceleration advantage over 30-06 when using projectiles of the same proportion with respect to caliber. Mass goes with the cube of the caliber were force is only going with the square of the caliber.

30-06 270 Win​
MAP: 60000, 65000
diameter: 0.308, 0.277
area: 0.074506, 0.060263
force: 4470.361, 3917.083
Mass: 180, 130.9362
Acceleration: 5.59E+06, 6.74E+06

:D
Click to expand...
In plain talk, get a 7-08, use the .243, or a 7 rem mag, or a 6.5 Norma and be happy that they work so well that the ammo companies and barrel makers still support them!
 
I have rifles in all 3 calibers. Many deer have been taken with .243, personally, I think it is a bit light for that. I like the 7x57 best of the 3, but if I could only have 1 rifle in the 3 calibers you have it would be the .270. Only reasoning behind that is availability of factory ammo, you can get it almost anywhere. That said, the rifle I use the most is a sporterized 6.5x55 Swedish Mauser. Shoots great, excellent accuracy.
 
dak0ta said:
There was another caliber that is lost to history of time, the .280 Ross (7mm). It was designed for the Canadian Ross Rifle, but rejected in favour of the 303 British. First practical cartridge to best 3000FPS using a 140g bullet. Performs similar to 270 Win and 280 Rem. In its day, it was superior to 7x57. I think it was first cartridge to be classified as "magnum". It's a semi-rimmed design. As a game round, it propelled the bullets of its day too fast causing fragmentation and failure on heavy game. Fine for CXP2 game, but unreliable for CXP3. 270 Win came around in 1925 and the rest is history.

View attachment 919720
303B(L), 280 Ross (R)
https://en.wikipedia.org/wiki/.280_Rosshttps://en.wikipedia.org/wiki/.280_Ross
Click to expand...
And another which is my preference in 7mm / .284: the 7X64mm Brenneke with traditional 1:8.67 inches rifling rate of twist with.30-06-ish shell size & capacity yet not a member of either the .30-03 or .30-06 cartridge families, that was born in 1917 specifically for use in the bolt action hunting rifle and already ready for the high BC 7mm projectiles that became available in the 21st Century such as the Nosler ABLR's. Norma factory ammo 7X64MM ammo has numerous options but the heavier for caliber ones are where it really stands out. Loaded with their 160 grain Tipstrike projectile, kinda a Swedish combination of Interlock and SST features, has a published muzzle velocity of 2919 fps and ammo loaded with their 170 grain Oryx projectile, a bonded semi spitzer style, has a published muzzle velocity of 2756 fps. That's within the 280AI envelope in factory ammo. There are no SAAMI entanglements as this is a CIP standardized cartridge.

That's before the .270 Winchester with typical 1:10 inches rifling rate of twist being produced in 1925, the .280 Remington with its typical 1:10 inch rifling twist rate produced in 1957, and the .280AI (post-1957 'cuz no .280 Remington, no 280AI) standardized by Nosler and accepted by SAAMI in 2008.

But I digress . . . but I'm not alone.:D
 
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mcb said:
First up you guys need to move into the 21st century and use SAAMI transducer pressures not CUP. Yes both cartridges are older than most of us but using modern measurements where possible is probably better and more accurate. SAAMI MAP using transducer measurements is 60,000 psi for 30-06 and 65,000 psi for 270 Win. This brings 270 Win pressure advantage to ~8.3%

Next we can't stop at peak force we need to get to acceleration since velocity is ultimately what we are after and we need take into account the mass of the projectiles.

For a fair comparison I would suggest we should use two bullet that are exact copies of each other just scaled (up/down) from the other to the appropriate caliber. ie the proportions and features would be the same. If we accept this assumptions of exact scaling of the projectiles then a 180gr 30-06 bullet using classic scaling (ratios of the characteristic length cubed) would weight 130.9gr if scaled down to .277. Sort of freaky there ain't it. :D

Using these weights we would find that the peak acceleration for 30-06 is 5.59x10^6 ft/sec^2 where 270 Win is 6.74x10^6 ft/sec^2. So 270 Win has a 20% peak acceleration (at peak pressure). This advantage stays the same as long as the bullets are scales of each other. 220gr 30-06 = 160gr 270 Win, a 150gr 30-06 = 109 gr 270 Win etc.

For the same pressure behind each bullet 270 Win would have an 11% acceleration advantage over 30-06 when using projectiles of the same proportion with respect to caliber. Mass goes with the cube of the caliber were force is only going with the square of the caliber.

30-06 270 Win​
MAP: 60000, 65000
diameter: 0.308, 0.277
area: 0.074506, 0.060263
force: 4470.361, 3917.083
Mass: 180, 130.9362
Acceleration: 5.59E+06, 6.74E+06

:D
Click to expand...
transducer pressures are not comparable between cartridges while crusher pressures are comparable. you proved this by quoting the transducer pressures and by pointing out the percent difference is different for the two different pressure measuring methods.

that said, there are a few more variables to consider in this "power" struggle. but i, for one, don't want to devolve into a discussion of minutiae. any handloader can reduce the charge of either cartridge and claim the other more powerful. i still consider these two cartridges of equal power. power comes from the amount of powder in the case anyway.

murf
 
troy fairweather said:
The rifles important to me, it was built for me when I was a kid. By the little know gunsmith John van patten, he was p.o.Ackleys shop Forman and worked with him in the collage to. John made many of ackleys chamber reamers to. This was his last rifle, he died only a month or so after he have me the rifle, he was 83 if I remember right.
Click to expand...


Beautiful....the nostalgia about custom rifle especially with memories is priceless.

buckmeister2 said:
All three are great. But, if you like the 7x57, you will faint over the 6.5x55. That is the single most underappreciated, unknown cartridge in American. it's a LONG bullet, having unbelievable sectional density. It's like shooting a needle. Retains velocity and energy over a long distance, but the ballistics don't even show what a great round it is. JMO, it is worth a look for any antlered game, and for targets.
Click to expand...
Availability of modern ammo in x57 seems an issue with many but it is not rare. Still available. The issue is more with modern rifle offerings in x57. That will drive the ammo demand. I guess on issue may also be that x57 isn’t patronized by any big names. Its kind of out there on its own. May be we are the last generation who will consider it seriously.
 
murf said:
transducer pressures are not comparable between cartridges while crusher pressures are comparable. you proved this by quoting the transducer pressures and by pointing out the percent difference is different for the two different pressure measuring methods.

that said, there are a few more variables to consider in this "power" struggle. but i, for one, don't want to devolve into a discussion of minutiae. any handloader can reduce the charge of either cartridge and claim the other more powerful. i still consider these two cartridges of equal power. power comes from the amount of powder in the case anyway.

murf
Click to expand...
You have that exactly backwards. Crusher measurements cannot topically be compared between cartridges. The Transducer method can. Crusher only gives you one number that is suppose to represent peak pressure but is reality a bad integral of the entire pressure event. The transducer method gives you the entire pressure vs time curve.
 
Newtosavage said:
I get the feeling some folks here have forgotten the original question.
Click to expand...
That usually happens with most of the threads that are debated with interest because at some point things lead astray. Hence beauty of human interaction.

Just read through the threads and find relevant info etc.
 
hossfly said:
LoL. The arguments over an inch or two at 400 yards....

The OP specifically asked about 243, 7x57, and 243. I don't really understand why those are the 3 he's deciding between, but I assume he has his reasons. I would say it really should depend on what he wants to do with it, whether he's going to load for it, etc.

The whole 270 - 30-06 thing is such a rare debate. <----- Massive sarcasm in case you didn't pick up on it.

They are the same thing. 270 is necked down 30-06 as I assume most of you know. Same pressure, etc. Do you want a little more frontal area or a little lighter bullet for the ballistic coefficient. Both of them have dropped more game than all of us can count and you won't go wrong with either one.
Click to expand...
After having great success with the .270 Win over several years, I gave my .30-06 to my son and he loves it, but he doesn't shoot as far (successfully) as I do.
 
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