Say, there is a possibility that the 30carbine is inherently inaccurate because it headspaces on the case mouth. Mass produced cases of the day may not have had the tolerances for consistent head spacing.

Larry,

Im not sure what worn out bores has to do with a cartridges reputation either good or bad but OK!!

I wonder if the 7X57 would have been considered more of an "inherently accurate" cartridge if it were not for the ultra deep throat they are usually found with. ??

quote:

Originally posted by Wstrnhuntr:
Larry,

Im not sure what worn out bores has to do with a cartridges reputation either good or bad but OK!! NOT A THING !

I wonder if the 7X57 would have been considered more of an "inherently accurate" cartridge if it were not for the ultra deep throat they are usually found with. ??

Quite possibly and the key word being "CONSIDERED". Long throats are not an accuracy deterent used with the right long bullets like in long range with VLDs roger

quote:

Originally posted by bartsche:

quote:

Originally posted by Wstrnhuntr:
Larry,

Im not sure what worn out bores has to do with a cartridges reputation either good or bad but OK!! NOT A THING !

I wonder if the 7X57 would have been considered more of an "inherently accurate" cartridge if it were not for the ultra deep throat they are usually found with. ??

Quite possibly and the key word being "CONSIDERED". Long throats are not an accuracy deterent used with the right long bullets like in long range with VLDs roger

I agree with bartsche.

Larry Gibson

quote:

Originally posted by Wstrnhuntr:
Larry,

I wonder if the 7X57 would have been considered more of an "inherently accurate" cartridge if it were not for the ultra deep throat they are usually found with. ??

Many long-throated calibers in individual rifles have proven that they can be accurate - this goes for most German made rifles in 7x57 and the 7x64 that features an even longer throat. What we learn out of this is that it is mostly to do with concentricity of the cartridge relative to the chamber and bore. That involves precision made rifles and careful reloading practises and the selection of precision made bullets.

I shoot clover leave groups with my K98 custom-made 7x57 mm, using federal factory ammo in 140 gr bullets. This happend during a test at the manufacturer before I took delivery. The PMP 170 gr ammo gave a slightly wider group, but still very good.

Warrior

quote:

Originally posted by 303Guy:
Would the bullet typically loaded in a cartridge influence its reputation for 'inherent' accuracy? I have been given the impression that the Lee Enfield was capable of surprizing accuracy from shot out and/or corroded bores. The 303 Brit was typically loaded with a Mk7 174gr bullet which is quite long and all that. Before I rebarreled my LMLE I was told by the range officer Sergent Major to just shoot the rust out the barrel. It didn't help! I did manage to land my shots onto the target at 600m but nowhere near an actual score.

SMLE's tend to shoot better than you'd think with edgy bores because of their Rifling. Early on they swithched over from a narrow groove type Metford rifles to a deeper style that would last longer shooting erosive Cordite ammo. It was a good choice, I've had a few SMLE's that had bores that looked like a potato patch and still shot 2 MOA or so groups.......................DJ

I will take the potatos, thank you !!!



Warrior

quote:

Originally posted by djpaintles:

Let me squish the tseste fly. If under controlled conditions your "group" is not in the center of the target it's merely a matter of sight adjustment to get them there.

Under NON controlled conditions (i.e. outdoors in a match) hitting the center of the target is effected by wind, mirage and other conditions that have nothing to do with the inherant accuracy of a round.

By definition how could environmental conditions effect something inherant in a round itself? I think this is where a lot of people get confused about "inherant accuracy", while a 338 Lapua would shoot better groups at 1000yds than a 22 long rifle it wouldn't necessarily do so indoors at 25 meters. So if you want to define "inherant accuracy" you have to limit the definition to accuracy in controlled condition where external conditions aren't changing things........................................DJ

I hate to say this dj, but you not only didn't squish the tsetse fly, you didn't even touch it, or apparently even see it.

The point was that accuracy does not even have a set definition, so it is difficult to say one cartridge is inherently more accurate than another.

Shooting on score targets, the round which scores the higher score is considered "most accurate", while in group shooting the one which scores the smaller group is considered most accurate. And that is NOT just a function of centering the group on the target.

Believe me, there is a reason benchrest competiors use the 6 PPC for smallest groups, and .30-BR for highest scores. And that difference is NOT inability on their part to center their groups!!

Which is the most accurate? Depends on what one is trying to achieve, doesn't it?


An example:

Let's say an average 6 PPC fires a group which is .007" smaller than the groups fired by an average .30-BR. Which is the more accurate? If smallest group is the goal, then clearly the 6 PPC is.

On the other hand, if the 6 PPC misses the dot which is the "X" of a score target, the .30-BR may still very well hit the dot, even though the center of its bullet hole may be farther away from the dot than the center of the 6 PPC bullet hole. After all, the .30 BR is .044" bigger in diameter. So, a shot which is a complete miss by .003" with a 6 PPC will still be hit by a .30-BR even if he BR places the center of its bullet hole .018" farther from the center of the dot.

So for score shooting the cartridge with the larger group may still be more accurate, i.e., make the higher score.

Translated to varmint shooting, a 6 PPC which misses a prairie dog by .003" has missed entirely. It has done just & only, that, missed. A shot from a .30-BR which might have the center of its bullet .005" farther away from the "dog" than the 6 PPC bullet, still puts .010" of its bullet into the prairie dog. That's equivalent to 40% of the diameter of a 6 mm round hitting the prairie dog.

Which is the most inherently accurate round?

For prairie dog shooting? The one which misses the prairie dog, or the one which hits it?

Accuracy ;
1. the condition or quality of being true, correct, or exact; freedom from error or defect; precision or exactness; correctness.
2. Chemistry, Physics. the extent to which a given measurement agrees with the standard value for that measurement.
3. Mathematics. the degree of correctness of a quantity, expression, etc.

Accuracy is the degree of veracity while precision is the degree of reproducibility. The analogy to explain the difference between accuracy and precision is the target comparison. In this analogy, repeated measurements are compared to bullet holes that are fired at a target. Accuracy describes the closeness of bullets to the intended point of aim presumably at the target center. Bullets that strike closer to the bullseye are considered more accurate. The closer a system's measurements to the accepted value, the more accurate the system is considered to be.


Thus logic would favor a smaller diameter projectile to a predetermined distance and a progressively larger diameter as well as heavier projectile to a greater distance .

One mans opinion .

"The world is a dangerous place to live, not because of the people who are evil, but because of the people who don't do anything about it."
Albert Einstein

DAMM!!!! Roger you sure stired the pot with this one.
lYLE

I find this subject fascinating! You folks out there have a tremendous combined experience and knowledge and I enjoy 'listening' to you all!

Some folks have been reporting under 'medium caliber' that they have found the 270 Win to be an accurate rifle/cartridge even with factory ammo. Could it be a combo of long neck, large case to bore diameter and a low expansion ratio and slow powder but giving it a lot of time and pressure to burn properly and consistently? These same conditions would exist in the 243, which is also said to be accurate.

bartsche, you started this, so, what have been your findings? Seriously, I mean - this is real interesting!

quote:

The 308W is one of them. But all of the others are equal to the 308W in terms of accuracy. So you'd have to say that they all are inherently accurate?

Maybe the truth is that all or most cartridge designs are potentially accurate, but some just happen to lend themselves to better accuracy due to the fact that they are more forgiving of manufacturing errors?

I gave the example of my hornet liking a very hot load of one particular powder. It just so happens that that powder allows me to load a very compressed charge in my particular gun with one particular make of brass and a heavy bullet which others have found to be accurate in their guns. That loading is over SAAMI spec and is a one off, so that would make it impossible to be a factory load. (Although, I am under the impression that this powder and other good bullets are now being factory loaded for the hornet).