quote:

Originally posted by TEUTONIC:
why people ything that velocity is first factor in clean killing of animals,sorry for my english and ignorance but velocity doesnt kill,MOMENTUM IS A FACTOR,i have more confidence of taking animals with medium fast cartidges than magnums,dont tell u will kill big bear any better with 300 win mag than i will with 9.3,actually is a man behind a gun whonever caliber he shoots

I understand what you mean, but velcity IS as important as momentum in killing.

How's that? Well, momentum is meaningless if you don't hit the target in the right place. More velocity makes flatter trajectories, and flatter trajectories deliver easier accurate bullet placement.

In game shooting as in much else, it takes two to tango....i.e. velolcity and momentum. (And BTW, velocity contributes proportionally to momentum, as momentum is calculated by weight (mass) x velocity.

quote:

Originally posted by Alberta Canuck:
In an emergency it would be just point and shoot, and a scout scope would get in my way.

ME TOO!!

I know it has something to do with my innate "weirdness", but I detest scout scopes. For me they do not work, and I have tried half a dozen of them.
[/QUOTE]
KB and AC, Hot Core would fit just fine at your Camp fire. I must admit the up front scope is a bit off thread intent. roger

quote:

Originally posted by bartsche:

KB and AC, Hot Core would fit just fine at your Camp fire. I must admit the up front scope is a bit off thread intent. roger [/QUOTE]

I'm not sure I get the intent of your message, Roger, but ANYONE and EVERYONE is welcome at my campfire so long as they are polite and friendly.

quote:

One thing folks forget when comparing the 30-06 with the 8x57 and thinking the 06 will throw the heavier bullets better because of more capacity is that the 8mm bore creates more volume faster then the 30 caliber and you can get more out of that 8x57 case because of that.

In my experience the 8X57 will push almost 20 grains more bullet weight @ a given MV compared to the .06 when the pressure is equal.

The .323 bore has 10% more base area than the .308 for the pressure to act upon & the case capacity advantage of the '06 is not that much greater than the 8X57.

AND bullets in the 200gr flavor are IMO the most effecient in the 8X57 as far as MV compared to down range energy while in the .308 it's more in the 165gr range..

quote:

Originally posted by wildcat junkie:

quote:

One thing folks forget when comparing the 30-06 with the 8x57 and thinking the 06 will throw the heavier bullets better because of more capacity is that the 8mm bore creates more volume faster then the 30 caliber and you can get more out of that 8x57 case because of that.

In my experience the 8X57 will push almost 20 grains more bullet weight @ a given MV compared to the .06 when the pressure is equal.

The .323 bore has 10% more base area than the .308 for the pressure to act upon & the case capacity advantage of the '06 is not that much greater than the 8X57.

AND bullets in the 200gr flavor are IMO the most effecient in the 8X57 as far as MV compared to down range energy while in the .308 it's more in the 165gr range..

Your argument is strong, but flawed. I believe it would have been better to concentrate on sectional density instead of bullet weight only. A quick glance at Hornady's 4th edition shows a 220 grain .323" bullet possesses a s/d of .301 and that the 220 grain .308" bullet has a s/d of .331. Although identical in weight, the "work" accomplished will be different if launched at the same velocity. The former will always have more frontal area, and the latter will always have a greater sectional density. With this in mind Hornady's great 195 grain .323" (s/d .267) more closely compares with the 180 grain .308" (s/d .271), not the 165 grain (s/d .248) bullet.

P.S. Hunting bullets that offer serious penetration start where sectional density is above .260 IMHO.

hpw about 6.5x55 and 140 grain SD

quote:

Originally posted by TEUTONIC:
hpw about 6.5x55 and 140 grain SD

I believe the 140 grain bullet in 6.5 calibre is ideal. Hornady lists their fine 140 grain spitzer as having a s/d of .287. Anyone who has used it knows it's a great choice and effective beyond what the cartridge size indicates.

quote:

Originally posted by Alberta Canuck:

quote:

Originally posted by bartsche:

KB and AC, Hot Core would fit just fine at your Camp fire. I must admit the up front scope is a bit off thread intent. roger

I'm not sure I get the intent of your message, Roger, but ANYONE and EVERYONE is welcome at my campfire so long as they are polite and friendly.[/QUOTE]
Hot Core dislikes scout rifles also. No evil intent. roger

roger,
I didn't mean to imply that I don't like scout scopes/rifles. It's just that I'm not comfortable using one, since I've not spent the time to become accustom with them. Those that I've looked through seemed like an odd sighting device, not quick at all as intended. Until I can get a better impression of them, I ain't spending money there. Since I don't have one, and don't have any hunting or shooting buddies who does, it aint likely that I'll ever use one.

As for Hot Core, I wasn't among those on his troll list, so we got along fine.

Right now I would really like to be in a place where a camp fire is a good idea. This time of year, I'm getting darn tired of snow and cold. Winter camping aint my idea of fun, right now, in Alaska. However, deer camp in Texas this time of year is another story. They have a wood stove in the bunk house.

Usually I'm in Texas right now, hunting hogs. I didn't go this year for a variety of reasons, and I'm feeling pretty sorry for myself.

KB

I think a 200 grain bullet is just about right for a 8x57 with a 20" barrel - that's what I used in my Mannlicher last summer in RSA - dropped a big Waterbuck no problem. Around 2,400 fps.

I would be interested to know what brand 220 grain bullets you have?
I have an 8 x 57,X60S and 8x63 I would love to test them out.

A 220 gr. bullet at about 2300 FPS in your 20 inch barrel is pretty deadly, and penetration is outstanding..I'd shoot about anything with it under say 200 yards. that is about a duplication of our grand old 30-06...Thats pretty damn high praise in my books.

quote:

Originally posted by Atkinson:
A 220 gr. bullet at about 2300 FPS in your 20 inch barrel is pretty deadly, and penetration is outstanding.

I can hardly wait to give it a try.

My CZ 550 in 8x57 should be back from the gunsmith any day now. I had it bedded into a McMillan stock, and the barrel shortened.

I made a mistake when I ordered the stock from McMillan, and told them to make the LOP 13.5", which is what I've used for Mausers. I thought it was normal in general for all the usual bolt action rifles. When it arrived, I discovered that it is at least 1/2" shorter when the barreled action is actually set in the stock, and put to my shoulder. At first I thought it was a disaster, and the stock wasn't going to work as is, and as you know McMillan stocks aint cheap.

So I mounted a scope just to check eye relief and see how it fit and shouldered with the scope in place. All the while I was thinking of quick handling, perhaps with a jacket on, etc. As it turned out, the 1/2" shorter is a blessing, and I wouldn't have thought to order it that way on purpose. The is still plenty of eye relief, and it's much quicker to shoulder. I would really hesitate to try the shorter stock on a heavy kicking rifle, but for this 8x57 I'm rather sure it will work out just right.

KB

quote:

Originally posted by buckshot:

quote:

Originally posted by wildcat junkie:

quote:

One thing folks forget when comparing the 30-06 with the 8x57 and thinking the 06 will throw the heavier bullets better because of more capacity is that the 8mm bore creates more volume faster then the 30 caliber and you can get more out of that 8x57 case because of that.

In my experience the 8X57 will push almost 20 grains more bullet weight @ a given MV compared to the .06 when the pressure is equal.

The .323 bore has 10% more base area than the .308 for the pressure to act upon & the case capacity advantage of the '06 is not that much greater than the 8X57.

AND bullets in the 200gr flavor are IMO the most effecient in the 8X57 as far as MV compared to down range energy while in the .308 it's more in the 165gr range..

Your argument is strong, but flawed. I believe it would have been better to concentrate on sectional density instead of bullet weight only. A quick glance at Hornady's 4th edition shows a 220 grain .323" bullet possesses a s/d of .301 and that the 220 grain .308" bullet has a s/d of .331. Although identical in weight, the "work" accomplished will be different if launched at the same velocity. The former will always have more frontal area, and the latter will always have a greater sectional density. With this in mind Hornady's great 195 grain .323" (s/d .267) more closely compares with the 180 grain .308" (s/d .271), not the 165 grain (s/d .248) bullet.

P.S. Hunting bullets that offer serious penetration start where sectional density is above .260 IMHO.

You did not choose the read my post carefully.

I cited the compromise of MV & downrange energy. (ballistic coefficient) I DID NOT cite sectional density as W/todays expanding bullets SD IS A MOOT POINT.

SD is only valid for slow moving lead bullets that do not expand or solids.

SD goes out the window as soon as the frontal area of the bullet expands beyond the original shank diameter of the bullet.

Also SD DOES NOT take the nose shape of the bullet into account. A pointed spitzer bullet will penetrate farther in most cases than a round nose bullet of similar SD & in fact it can even out penetrate the RN W/a greater SD.

SD is such a dated term I do not know why so many even consisder it valid in most cases.

SD is nothing more than the ratio of frontal area to wieght.

A properly contructed bullet for the application of approriate caliber W/a good BC will have all the SD needed to get the job done.

KB - you have a PM

I would mosey on over to the Shooters Pro Shop and buy a pile of 200 gr Partition seconds for $17 a box and call it good. In fact, I did just that.

quote:

Originally posted by Boxhead:
I would mosey on over to the Shooters Pro Shop and buy a pile of 200 gr Partition seconds for $17 a box and call it good. In fact, I did just that.

I bought 600 of them, and 600 of the Custom Competion for plinking.

Wildcat junkie:

SD is not valid but BC is ? And SD only valid in slow moving bullets?

How can that be?

SD is nothing other than a mathematical expression of a body's inertia. For a body in motion the ratio of it's mass ( not weight) to the cross sectional surface area of it's persenting part in the direction of it's motion

Simply put as Newton showed a body at rest wants to stay at rest and it resists being moved by virtue of this entity called SD.

By the same token once in motion it resists change in motion again by virtue of the magnitude of it's inertia to change... again SD.

Hence a bullet with High SD will require more energy to be moved from rest than a low SD bullet and once in motion if the same bullets are subjected to an external force seeking to retard it's motion the HIGH SD bullet will be more resistant to change than the LOW SD bullet.

As for BC it is a mathematical coefficient described by the ratio of that body's magnitude of inertia to it's form factor.

Ie BC = SD/i

For long range shooting we see that High SD bullets trump low SD bullets if the form factor is the same.

It's not a question whether SD was valid yesterday and no longer today..... it is always valid always will be. It's a physical fact of living on earth !

quote:

Originally posted by ALF:
Wildcat junkie:

SD is not valid but BC is ? And SD only valid in slow moving bullets?

How can that be?

SD is nothing other than a mathematical expression of a body's inertia. For a body in motion the ratio of it's mass ( not weight) to the cross sectional surface area of it's persenting part in the direction of it's motion

Simply put as Newton showed a body at rest wants to stay at rest and it resists being moved by virtue of this entity called SD.

By the same token once in motion it resists change in motion again by virtue of the magnitude of it's inertia to change... again SD.

Hence a bullet with High SD will require more energy to be moved from rest than a low SD bullet and once in motion if the same bullets are subjected to an external force seeking to retard it's motion the HIGH SD bullet will be more resistant to change than the LOW SD bullet.

As for BC it is a mathematical coefficient described by the ratio of that body's magnitude of inertia to it's form factor.

Ie BC = SD/i

For long range shooting we see that High SD bullets trump low SD bullets if the form factor is the same.

It's not a question whether SD was valid yesterday and no longer today..... it is always valid always will be. It's a physical fact of living on earth !

SD is just so simplistic.

It has little relevance W/today's premium expanding bullets that will expand quickly for maximum tissue distruction (thus lowering effective SD) while still retaining as much weight as possible for better penetration. (retaining as much effective SD as possible)

As bullet expandes it's effective SD falls dramatically. That is what makes SD of little relivance.

Now, large caliber non expanding or very limited expanding bullets do have relevant SD & thus better penetration.

SD does not take the bullet shape into consideration, BC does.

Yes higher BC does = higher SD, but it not a linear equasion.

BC just takes more factors into consideration than SD.

If we are considering RN soilids for dangerous game @ close range, then SD is very relevant as there will be no other factors to consider.

The same could be said for BP cartridges that use relatively hard cast lead bullets @ velocities that do not significantly deform the bullets.

Neither factor takes all things into consideration. It's not that simple.

Niether SD nor BC are relevant if the caliber is not adequate for the job.

Wildcat junkie:

I do not follow your logic at all???

Alf, what ballistics program do you use when shooting, and does it ask for the bullets SD, or it's BC?

BC is for those who shoot through paper and air.
SD is for those who shoot through moose and bear.

KB

Agreed, KB.

Antelope sniper:

I do not use a ballistic program but I do know something about physics.

it is simple: a body with larger mass will hold it's downranage velocity better than body of less mass given the same projected surface area and shape...... that is why long range bullets are high SD bullets not low SD bullets.

The same applies when you have to accelerate the same two bodies to the same muzzle velocity..... you have to expend more energy getting the high SD bullet to move than the low SD bullet. This is a fundmental principle in gun design, or rocket design or design of internal combustion motors.

It is the SD of the projectile that you wish to shoot that determines how much propellant you will have to use and how strong the gun and gun tube design has to be the withstand the amount of pressure you will need to generate to give the desired velocity.

Once both bullets are in motion and they impact a target, if none of the two deform fragment or loose stability the High SD bullet would be more resitant to change in it's motion status than the light bullet.... ie the high SD bullet will be more resitant to the forces that act to impdede it's forward progression in motion.

Thus they penetrate the target better than the low SD bullet because it's higher inertia to change when compared to the low SD bullet.

Its all about mass, and the effects of mass in motion.

The old analogy of the ping pong ball vs the steel ball of same diameter..... if both impact a target at the same velocity the steel ball will penetrate the target more than the ping pong ball.

The problem with SD as we have have come to dummy it down in reloading manuals is that this defintion is not the true definition of SD as it pertains to a body in motion.

The true definition of of SD is defined as the ratio of the body's mass ( not weight) to the cross sectional surface area of it's surface presented or projected in it's direction of motion.

This very very different to the definition given by the loading manuals.

For one the Load manual definition assumes a static unchanging value..... this is wrong becasue the bullet is in motion and the surface area projected in the direction of motion is dynamic. Our bullets spin, they preceed and nutate, not only that they act and react on the fluid ( air) that they are in, dependent of their velocity .

Enter then the concept of BC:

BC is none other than a coefficient derived from the ratio of SD ( which is dynamic not static) to a form factor termed i.

We know that BC is velocity dependent, ie it is dynamic, so then if BC = SD/ i and i remains constant then SD has to be dependent on velocity changes . In real life it is.

And if your ballistics program does not actually ask for SD it actually is doing it, but you do not know that it is actually using SD in it's calculations.

Right on Alf. And SD is a critical component required in calculating BC.

As it relates to cross sectional area, it also has nothing to do with a relation to nose area as was previously stated, as the longer a bullet's nose, given a particular ogive, the greater the nose area...and that dimension is not taken into account in calculating SD, IIRC.

AC :

In reality the cross sectional area of the presenting part of the bullet is also strictly not the true effective area, the only area of concern is the effective "wetted" area. ie that part of the area that physically interacts with the medium it is in.

If we look at drag we see that at low velocities the whole bullet body comes into contact with the medium it finds itself in so that the whole surface of the projectile becomes wetted , hence the phenomenon of increase in drag just before the bullet comes to a stop in the target. Usually when velocity drops to below 200fps.

In a flat meplat solid bullet moving meplat forward , it's is only the meplat surface that is wetted hence the reduced drag and therefore reduced resistance to penetration that these bullets have when compared to RN solid bullets. it's an important mode of drag reduction and one employed in modern Naval warfare

It also then explains why their actual cavities permanent and temporary are smaller than RN bullets ( As drag is a function of wetted surface area and the size of the TC is a function of drag it explains why low drag projectiles in dense media have smaller TC's.

I buy and undertand that Alf. I was not commenting on BC with that comment about cross-sectional area, but about SD. To the degree SD is expressed in weight (mass, really) vs. surface area...I was just pointing out that the whole surface area of the nose (meaning all the area surface(s) forward of the bullet shoulder's commencement) is not what is usually used in calculating SD for sporting rifle bullets.

It is certainly understandable that the meplat, or probably some slight mathematically adjusted exaggeration of that dimension, would be more expressive of penetrating ability.

Anyway, SD IS important in maximizing penetrtion.

Whether correct in the way we calculate it or not, pretty much all hunters know from practical experience that more mass in a bullet of given diameter will penetrate better when propelled above some threshold speed than will a less massive bullet of the same diameter and materials.

And obviously too, that is true only so long as the bullet "flies" through the flesh without excessive yaw, and does not tumble.

That in turn is why often a RN bullet will penetrate better in actual field application to game than will a more pointed bullet. Being shorter, RN bullets require less spin to stabilize and to keep that stability.

Even if one does not agree with that reasoning either, it is pretty clear from empirical observations that RNs are less inclined to tumble in flesh than are longer, more pointed bullets of the same diameter. And if they also have greater SD, well then, HOORAY!!

Anyway, the bottom line is that I think KB is going the right direction in his quest. He should end up with some pretty effective ammo.

quote:

Originally posted by Kabluewy:
BC is for those who shoot through paper and air.
SD is for those who shoot through moose and bear.

KB

Very reasonably said.