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Old 06-01-2014, 02:15 PM
 
Location: San Diego
32,807 posts, read 30,061,070 times
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Quote:
Originally Posted by attrapereves View Post
That pressures seem to fluctuate and can go from safe to unsafe quickly.

Isn't that more from the powder you are using?
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Old 06-03-2014, 11:29 AM
 
Location: Midwest
978 posts, read 1,525,420 times
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Quote:
Originally Posted by 1AngryTaxPayer View Post
Isn't that more from the powder you are using?
Yes, powder does matter. However, slower burning powders are more stable and should be used in most overbore cartridges. In general overbore cartridges are more sensitive to pressure as you are dealing with a small opening. Anything with a smaller caliber bullet, but large case capacity can be very sensitive to pressure. Think about a water hose. If you slightly close the tip of it, pressure increases.

22-250, 25-06, and even 270 are definitely overbore cartridges meaning that they are inefficient for the bore diameter, and the amount of powder used (small bore, but a lot of powder used). These cartridges are often very high pressure which can lead to diminished barrel life. A 30-06 rifle will have a longer service life than a 22-250.

Here's a list of common overbore cartridges: “Overbore” Cartridges Defined by Formula within AccurateShooter.com
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Old 06-03-2014, 12:44 PM
 
Location: SW MO
656 posts, read 955,604 times
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Quote:
Originally Posted by 1AngryTaxPayer View Post
Isn't that more from the powder you are using?
Yes, especially if somebody is making a compressed charge. Those are notorious for being very touchy with chamber pressure.

Quote:
Originally Posted by attrapereves View Post
Yes, powder does matter. However, slower burning powders are more stable and should be used in most overbore cartridges. In general overbore cartridges are more sensitive to pressure as you are dealing with a small opening. Anything with a smaller caliber bullet, but large case capacity can be very sensitive to pressure. Think about a water hose. If you slightly close the tip of it, pressure increases.
Slower-burning powders are essentially required by overbore cartridges unless you want them to perform exactly like their slower, smaller-cased cousins. Without getting into a bunch of physics and calculus, the only way to increase the velocity of a specific bullet in a specific barrel is to increase the burn time of the powder. Pressure issues are more common to overbore cartridges for a few main reasons:

- They are usually loaded at or very near maximum pressure as to maximize their velocity potential, which is usually their only advantage over smaller-cased cartridges. There isn't nearly as much "wiggle room" between maximum safe loads for the rifle action and unsafe loads compared to cartridges loaded to lower pressures. Also, reloaders making loads for a cartridge noted for its high velocity are much more likely to try to push the envelope compared to folks who bought a "fuddy-duddy" lower-pressure, lower-velocity round.

- They are loaded with a relatively large powder charge and as such they are proportionally less tolerant to differences in powder burn rates and compression of the powder charge than cartridges with less powder.

Quote:
22-250, 25-06, and even 270 are definitely overbore cartridges meaning that they are inefficient for the bore diameter, and the amount of powder used (small bore, but a lot of powder used). These cartridges are often very high pressure which can lead to diminished barrel life. A 30-06 rifle will have a longer service life than a 22-250.
The maximum pressure of most modern rifle cartridges are very similar as that is determined by the yield strength of the metals in their actions. For example, the .308 Winchester and .30-378 Weatherby Magnum have a maximum pressure which is nearly identical (62000 vs. 63817 psi) despite the .30-378 being a much larger cartridge able to drive similar-weight bullets about 800 fps faster. The reason that the overbore cartridges lead to lower barrel life is due to them driving bullets faster. Bullet velocity is what kills barrels and why a .308 barrel lasts a lot longer than a .30-378 Wby barrel.
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Old 06-13-2014, 08:40 PM
 
919 posts, read 1,668,417 times
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The Maximum effective range on a 100gr bullet in a 243 is 350yards! My dad was involved with Winchester when they brought it out in 1955. Please don't bs me it barely adequate . It is far superior to the 30/30 an that has killed at least a trillion deer. I have shot a ton of things with the 243 including mule deer it is a great caliber you don't need magnums to kill a deer.
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Old 06-16-2014, 03:22 PM
 
Location: San Diego
32,807 posts, read 30,061,070 times
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Quote:
Originally Posted by mark6052 View Post
The Maximum effective range on a 100gr bullet in a 243 is 350yards! My dad was involved with Winchester when they brought it out in 1955. Please don't bs me it barely adequate . It is far superior to the 30/30 an that has killed at least a trillion deer. I have shot a ton of things with the 243 including mule deer it is a great caliber you don't need magnums to kill a deer.
I'm getting a .243 for my Son specifically because his .264 AR is: A. Too heavy B. Too loud to load ~ I won't let him carry loaded for now as he's 12. A bolt .243 will fit the need perfectly. I've even thought about a single shot.
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Old 06-16-2014, 04:34 PM
 
7,282 posts, read 8,390,715 times
Reputation: 11407
Quote:
Originally Posted by Flyover_Country View Post
Yes, especially if somebody is making a compressed charge. Those are notorious for being very touchy with chamber pressure.



Slower-burning powders are essentially required by overbore cartridges unless you want them to perform exactly like their slower, smaller-cased cousins. Without getting into a bunch of physics and calculus, the only way to increase the velocity of a specific bullet in a specific barrel is to increase the burn time of the powder. Pressure issues are more common to overbore cartridges for a few main reasons:

- They are usually loaded at or very near maximum pressure as to maximize their velocity potential, which is usually their only advantage over smaller-cased cartridges. There isn't nearly as much "wiggle room" between maximum safe loads for the rifle action and unsafe loads compared to cartridges loaded to lower pressures. Also, reloaders making loads for a cartridge noted for its high velocity are much more likely to try to push the envelope compared to folks who bought a "fuddy-duddy" lower-pressure, lower-velocity round.

- They are loaded with a relatively large powder charge and as such they are proportionally less tolerant to differences in powder burn rates and compression of the powder charge than cartridges with less powder.



The maximum pressure of most modern rifle cartridges are very similar as that is determined by the yield strength of the metals in their actions. For example, the .308 Winchester and .30-378 Weatherby Magnum have a maximum pressure which is nearly identical (62000 vs. 63817 psi) despite the .30-378 being a much larger cartridge able to drive similar-weight bullets about 800 fps faster. The reason that the overbore cartridges lead to lower barrel life is due to them driving bullets faster. Bullet velocity is what kills barrels and why a .308 barrel lasts a lot longer than a .30-378 Wby barrel.
Quite a bit of inaccurate info in that post.

The maximum pressures of cartridges is not determined by the strength of the metals in their actions. That is nothing more than bad information.

Two different firearms chambered for the same cartridge can be made from different materials, including the materials from which their actions are made. The maximum pressure of cartridges is determined by the cartridge design, not the action materials used to make the firearm.

Overbore cartridges do not have lesser barrel life because they drive the bullets faster, they usually erode the barrels faster because of the hot gasses eroding the barrels. More to the point, it isn't bullet velocity that wears the barrel, it is the gases developed during firing and the materials from which the barrel is made and the composition of the bullet jacket or lack thereof and the bearing surfaces involved. Velocity is way down on the factors involved. Even the twist rate of the barrel is more of a factor than velocity when it comes to barrel wear and so is the design of the barrel such as conventional land/groove, polygon and other twist designs.

A lot of the comments you posted above don't wash.

Another is the statement that overbore cartridges are usually loaded close to or at maximum pressures as their advantage is also misleading to say the least. Please, spare the calculus and physics as you are implying your opinions are backed up by the which they are not.

Take the .17 Remington for example. It is one of the most popular over the counter overbore cartridges sold yet isn't loaded closer to maximum pressure than most others. The .17 Rem is very accurate and serves specific purposes very well.

The .17 when properly cared for doesn't wear barrels any faster than the .223 Rem and the FACT is that both are loaded to the same pressures and both have identical maximum pressures.

There is no factual evidence that reloaders push overbore cartridges more than they do any other cartridges. Those who reload and push pressures just do it because they do, not because of the cartridge being an overbore design.

Please, references to other forums are hardly references because so much bad information is little more than copied and pasted from forum to forum until people start believing it.

Last edited by Mack Knife; 06-16-2014 at 04:47 PM..
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Old 06-16-2014, 05:07 PM
 
7,282 posts, read 8,390,715 times
Reputation: 11407
Quote:
Originally Posted by attrapereves View Post
Yes, powder does matter. However, slower burning powders are more stable and should be used in most overbore cartridges. In general overbore cartridges are more sensitive to pressure as you are dealing with a small opening. Anything with a smaller caliber bullet, but large case capacity can be very sensitive to pressure. Think about a water hose. If you slightly close the tip of it, pressure increases.

22-250, 25-06, and even 270 are definitely overbore cartridges meaning that they are inefficient for the bore diameter, and the amount of powder used (small bore, but a lot of powder used). These cartridges are often very high pressure which can lead to diminished barrel life. A 30-06 rifle will have a longer service life than a 22-250.

Here's a list of common overbore cartridges: “Overbore” Cartridges Defined by Formula within AccurateShooter.com
That too is a lot of misunderstanding.

Most people don't understand what wears barrels. It isn't if the cartridge is overbore or not, high pressure or not, it is how the firearm is used.

You can wear out a barrel on a 30-06 rifle much faster than one chambered for 22-250 just by firing it quickly, not cleaning it and so on.

If you observe carefully, the typical shooter with a 22-250 vs one shooting the 30-06, something very apparent can be seen. The 22-250 shooter often heads out with a bag full of ammo, the 30-06 shooter, maybe a box, if that. A 22-250 shooter will knock off hundreds of rounds shooting 'dogs on a good long day, the 30-06 shooter might light off a few round at the range or hunting larger game. Of course the 22-250 barrel is going to wear faster. The barrel is going to get hot, the barrel material will then become more susceptible to erosion from the gases and so on. The 30-06 barrel might get warm, it that.

Overbore cartridges are not more sensitive to pressure because of a small opening. Large calibers can be overbore. The gases from the burning powder do not function the same way as water through a hose. The analogy doesn't work. Liquids and gases behave much differently, especially when the gas if formed by combustion.

All things being equal, the bullet going down the bore of rifle chambered for an overbore cartridge isn't going to wear faster because of that single factor to any significant degree than one than isn't overbore.

Barrel erosion is a factor of many things, the velocity of the bullet isn't the primary one of one even worth considering.

Gun magazine writers aren't resources worth citing, they sell advertising, not much else.
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Old 06-17-2014, 02:52 PM
 
7,282 posts, read 8,390,715 times
Reputation: 11407
Quote:
Originally Posted by TaxPhd View Post
Physics isn't my strong suit, but I'm pretty sure that felt recoil is much more a function of momentum rather than KE.
Your are correct, felt recoil has little to do with kinetic energy. Energy can be dissipated through a variety of methods to the point where two firearms firing the same cartridge in the same loading having the same kinetic energy will feel like two completely different firearms even though both are the same except for the method they use to dissipate recoil.

This has been proven as fact for so long it isn't something that should be open for argument, it is fact.
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Old 06-24-2014, 10:10 AM
 
1,176 posts, read 1,899,474 times
Reputation: 1397
Forget all the paper arguments.

A rifle chambered for .25-06 Remington is a great thing to have in your arsenal. It's a very potent hunting cartridge with a pussycat recoil. You'll love it.
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