>> 6.5 mm -- is this the "perfect" caliber ?

Started by LLANOJOHN (deceased), January 14, 2005, 03:22:22 PM

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gitano

Be nicer than necessary.

LLANOJOHN (deceased)

#61
Paul,
 
In reply to your request about velocities for the 85 grain bullet.....Well, I am a little disappointed with the powder data base in the LFAD program. But I will give you the results that I obtained.
 
85gr Sierra HP....65degree temp....36.9grs - 3031....3178fps.....22" barrel. Pretty good but...
 
I think a little faster burning powder might bring those velocities up a bit.....however 3178 in a 22" barrel is not bad for the "little feller"........The Grendel would probably be pretty close in all respects.
 
klallen & kombi1976..........Fellers...you are both right in your respective views. Kombi..you and I are in definite agreement on how we choose what we want to hunt with and it is based on where we hunt and what we hunt. The vast majority of my shots are 200 yards or less...usually much less...more like 75 or 80. The various bullet manufacturers that I have had the occasion to read say their bullets will expand as advertised down to about 1600fps. My choice for the best caliber/cartridge where I hunt would be the 260 Rem, 6.5x55 Swede or the 6.5x257 Roberts. These cartridges will do the job to 300yards or so efficiently, mild recoil and less expense over all than the 6.5/06 or any of the Ackley versions. Bear in mind that my "personal" recommendation for any of the Ackley versions is 100 rounds per year to be cost effective. I really don't know the terrain you hunt so my situation may be quite different than yours. We need to share descriptions of the terrain we hunt and see if they have simularities.
 
As to klallen.....well I have come 180 degrees since I first read his posts on this forum and other forums. What changed my opinion was the opportunity to watch a hunting program where they were after mule deer in eastern Montana. If I had false teeth, I would have dropped them right then and there. Sage brush up to about your knee was the largest plant I saw. The astronauts walking on the moon would have felt right at home. I understand now how & why klallen chooses the "high end" of cartridge ballistics for where he spends most of his time hunting. From what I have been able to discern he has also taken the time to acquire the skills necessary to make clean humane kills at long range. If I manage to make my 2006 trip to Arizona, New Mexico, Wyoming & Montana you can be assured I will look up klallen. I will be close to 64 years of age by then and getting a bit "long in the tooth" but I am not too old to learn a few new tricks. I sincerely hope that we can share some quality shootin' time and I can come back to Texas a whole lot smarter than when I left. Good Lord willin' and the creeks don't rise! Thats what this feller is a
hopin'!!!!
 
Ol' John
 
PS..kombi...little package in the mail to ya, neighbor.  Thank you for the nice e-mail and the pics........wish I could join ya in huntin' them 'roo's.  If I win the lottery you can expect an -e- as to when and where!  Your thoughts were greatly appreciated.  Best regards, OHIH.
Life Member-NRA-TSRA
Riflesmith-Bolt & Lever Centerfires Only
Left-Hand Creek Rifles
Mark Twain was right-"There is no such thing as too much good whiskey!"
My best advice.."Best to stay outta trees and offa windmills!"

kombi1976

Well, I should hope I'm not hobbling myself with efficiency either.
After all, if it doesn't do the job it isn't efficient.
But, yeah, I understand your philosophy.
You've poured a lot of time, effort and money into being able to hunt at long ranges and if your cartridge doesn't enable you to fulfil those aims, by my definition it's also inefficient, so long as you are satisfied with the way it operates and are comfortable with it's recoil.
Who am I to criticize your choices when you have such a extensive success rate?
I guess efficiency adds up to what each of us decides is permissable....in other words it's subjective.
So next time you line up on an elk at 300yds with th Warbird just remember I'd be standing behind you if I could smiling as you took it down, half because it was your shoulder taking the wallop, but mostly because I like to see fine shooting.
To give you a little insight into why my approach is different, most of my targets are usually 200yds at the most, partly because I hunt on farmland with other properties encroaching on either side, but also because I have far less experience and only take a shot I'm pretty convinced is possible for this bumbling halfwit to hit.
Don't get me wrong, I'm getting better but I think Jack O'Connor & definitely Elmer Keith would laugh long and hard at the amount of concentration I invest in each shot.
I think I've got extra wrinkles from the faces I pull. :p
Cheers & God Bless
22lr ~ 22 Hornet ~ 25-20 ~ 303/25 ~ 7mm-08 ~ 303 British ~ 310 Cadet ~ 9.3x62 ~ 450/400 N.E. 3"


gitano

#63
I agree about the powders John, and 3200 fps is probably a not a bad guess for a reasonable max considering a 22" barrel.
 
I'd have to play around a bit with bullets before I could choose one primary bullet for a 6.5 BR. Generally, I prefer heavy-for-caliber bullets in "small" calibers, but the 6.5 is a little "big" to be calling it "small". Hence "generalizing" makes me a little uncomfortable. At the moment, with only ancillary 6.5 experience, I'd say the 95 grain V-Max would be at the top of my list. However, a 100 grain Partition is something I'd look real hard at if it was available. I'd have to build one of my little "sweet-spot" graphs and see what that revealed. I think I'll do that and post the graph. Maybe that'll add constructively to what you've presented here. In order to do that for the 6.5 BR, I'll need some more LFAD data from you. I'll PM you.
 
Paul
Be nicer than necessary.

LLANOJOHN (deceased)

Paul,

In the 6.5 caliber Nosler Partitions can be had in 3 weights - 100gr, 125gr, 140gr!
 
Ol' John
Life Member-NRA-TSRA
Riflesmith-Bolt & Lever Centerfires Only
Left-Hand Creek Rifles
Mark Twain was right-"There is no such thing as too much good whiskey!"
My best advice.."Best to stay outta trees and offa windmills!"

gitano

Yeah I saw that when I looked in their manual. I would definitely look at the 100 grain Partition and the 95 V-Max. I'm still working on the "sweetspot" graph.
 
Paul
Be nicer than necessary.

LLANOJOHN (deceased)

#66
Quote from: sakorickafter reading each and every post in this thread....no... the 6.5 is not the perfect caliber. The 6.5x'06 seems to get in the top 10. Regards, Rick.:D
SR,
 
Well neighbor, lets hear your 'whys' and 'where fores'? Here at THL we request discussion among our members.
 
Ol' John..:cool:
Life Member-NRA-TSRA
Riflesmith-Bolt & Lever Centerfires Only
Left-Hand Creek Rifles
Mark Twain was right-"There is no such thing as too much good whiskey!"
My best advice.."Best to stay outta trees and offa windmills!"

gitano

#67
Here's the promised "sweetspot" graph. I generated graphs for the Swede, 260, 6.5-06, 6.5-284, 6.5 Rem Mag, and the 264 Win Mag. I chose the one from the 260 at 300 yds because they were all basically the same in shape. If you would like to see one of the others, just speak up. Each can be had for 100, 200 or 300 yds.
 
This exercise really surprised me. I've looked at a lot of these "sweetspot" graphs and this is the first caliber whose sweetspot didn't change significantly with cartridge. Not only is the 140 just about centered for all cases, it's also the best performer by quite a bit. In other calibers, the sweetspot will move left (to lighter bullets) with smaller cases. The bigger cases getting better performance out of the heavier bullets. In the 6.5 (.264"), regardless of case, the theoretical "best" performing (highest KE at a given range) bullet weight remains between 130 and 135 grains from the Swede to the 264 WM. Amazing - at least to me.
 
Paul
Be nicer than necessary.

CAfrica

Now that really is an interesting graph.  If you say it is also similar for the other 6.5's then it seems that the 140gr Nosler Partitions that I shoot in my 6.5-06 happens to be a good choice.  I'm still experimenting but I seem to be able to launch them at around 3000ft/s + from my 26"bbl.
 
I asume you'r basing this graph on published BC's and published velocities available in each calibre for each bullet?  So the "variance"between the 4 100gr bullets is due solely to a difference in BC?  Is that correct?
 
Regards.
 
C

gitano

#69
Quote from: CAfricaNow that really is an interesting graph. If you say it is also similar for the other 6.5's then it seems that the 140gr Nosler Partitions that I shoot in my 6.5-06 happens to be a good choice. C, after creating all these graphs, I think I'd go with Nosler's 125 Partition. Its performance is "close enough" to the 140s that I'd opt for the reduced recoil of the 125. This only because it's a Partition. I'm still experimenting but I seem to be able to launch them at around 3000ft/s + from my 26"bbl.
 
I asume you'r basing this graph on published BC's and published velocities available in each calibre for each bullet? So the "variance"between the 4 100gr bullets is due solely to a difference in BC? Is that correct? Absolutely. Most of the velocities came from P.O. Ackley, or Richard Lee. The BCs came from the manufacturer ofhte bullet. I set all bullets of the same weight to the same muzzle velocity. That is of course not technically correct, but I'm sure the differences are insignificant with respect to this exercise.
 
Regards.
 
Looks like I shoulda made these graphs before I bought all those "light" bullets. :o Actually, I did get some 129s. But truly, I like the idea of the 125 Partiton.
 
C
Paul plus 5
 
I've added a graph of the 6.5-06 at 300 yds for your perusal. Note the performance of the 125 relative to the 140s. In this analysis the 140s had a MV of 2939 fps (896 m/s), and the 125's was 3114 f/s (949 m/s).
Be nicer than necessary.

LLANOJOHN (deceased)

Paul,
 
As I understand your graph, a bullet selection of anything from 120 to 140 grains gives the max delivered energy to the game hunted at 300 yards.  Am I reading this correctly?  Based on my memory(oops!), the 120's like the Nosler BT would more than likely give the flatest trajectory to 300 but not by a whole lot as compared to the 140.  So for antelope, whitetail and mule deer or perhaps Bighorn sheep or Mountain goat, the 120 Nosler BT, 120 Sierra Gameking and the 125 Nosler Partition would be the bullets of choice to do the job required.  Given an accuracy maximum of 1.5" at 100 and 4.5" at 300 yards.  For elk or caribou, perhaps a selection of the 140grain bullets available would be the better choice.  I would think that the Nosler 140gr Partition would be the bullet of choice for moose.
 
What say you?
 
Ol' John..:confused:
Life Member-NRA-TSRA
Riflesmith-Bolt & Lever Centerfires Only
Left-Hand Creek Rifles
Mark Twain was right-"There is no such thing as too much good whiskey!"
My best advice.."Best to stay outta trees and offa windmills!"

gitano

Quote from: HondoJohn6508Paul,
 
As I understand your graph, a bullet selection of anything from 120 to 140 grains gives the max delivered energy to the game hunted at 300 yards. Am I reading this correctly? Absolutely correct John. Based on my memory(oops!), the 120's like the Nosler BT would more than likely give the flatest trajectory to 300 but not by a whole lot as compared to the 140. Here are the BCs for the respecive bullets.
120 BallisticTip - .458
120 Spitzer - .368
120 BTHP - .403
125 Partition - .449
140 Partition - .490
140 BTSP - .490
140 BTHP - .526
140 A-MAx - .550
140 SST - .520
140 Spitzer - .465

As you can see, the 140s 'hold their own' with BCs. But I would agree with your assessment below, except that I'd probaly choose a BallisticTip 140 for Moose. My experience with Partitions is that they penetrate very well, but they blow back to the partition, and have an expanded diameter of just slightly larger than nominal - only .264" in this case. I wouldn't be worrying about penetration if I could deliver 2000+ ft-lbs of energy with a Ballistic Tip. I'd rather have the bigger hole.
 
So for antelope, whitetail and mule deer or perhaps Bighorn sheep or Mountain goat, the 120 Nosler BT, 120 Sierra Gameking and the 125 Nosler Partition would be the bullets of choice to do the job required. Given an accuracy maximum of 1.5" at 100 and 4.5" at 300 yards. For elk or caribou, perhaps a selection of the 140grain bullets available would be the better choice. I would think that the Nosler 140gr Partition would be the bullet of choice for moose.
 
What say you?
 
Ol' John..:confused:
Paul plus 5
Be nicer than necessary.

CAfrica

Gitano,
 
Thanks for that graph.
 
For flatter trajectory and small targets, I am experimenting with the 110gr GS Custom HV. Because of the copper construction it is as big as a 125gr bullet (and has a corresponding high BC of 0,49).  I expect to launch these at about 3400ft/s.  I will give the lighter Noslers some thought but when I am shooting at bigger animals (especially at long range where my placement may be suspect), I would prefer a strong heavy bullet with penetration capability rather than high energy impact and would therefore rather stick with the 140 partition.
 
But then you know we differ on this subject.
 
Thanks again.
 
C

gitano

#73
CAfrica,
 
I think if the GS bullets were readily available, I would use them instead of Partitions whenever a partition-type bullet was called for.
 
Let's revisit the issue of 'penetration' again. Not to change anybody's mind about what bullet they should use, but rather to flesh the subject out a bit more keeping in mind some specific initial constraints.
 
We are considering bullets of a single caliber, 6.5 mm, and the exact same design, GS's Monolithics. Given these constraints, I would submit that the bullet that arrives with the most momentum will be the bullet that penetrates the farthest. As you well know, the formula for kinetic energy is half the mass times the velocity squared, and for momentum, it's simply the mass times the velocity. Therefore, without having to calculate the actual value for momentum, I know that the one with the highest KE also has the highest momentum. Since the bullets are of the exact same design, we can assume that they will have "exactly" the same terminal response. Therefore, the one with the greatest momentum should travel the farthest before the target medium stops it. If this is not true, one of two things are: 1) They DID NOT perform similarly in similar media, or 2) the laws of physics as we know them need to be revised. Therefore, if I was considering "penetration" as an important selection criterion, and I was selecting among bullets of identical design, I'd select the bullet that delivered the most energy to the target at the ranges I expected to shoot, and the weight, as a selector, would be immaterial. While the "sweetest" weight might very well be the 140, I wouldn't select the 140 until I had checked its momentum/delivered energy against bullets of other weights, muzzle velocity, and ballistic coefficient.
 
To that end, you have access to the weights, BCs and expected MVs of lots of GS bullets. If you'll send those along for the 6.5 mm and MVs for whatever cartridge you'd like to compare, I'll make up a GS sweetspot graph. For my two-cents-worth, I'd like to see velocities for one of the 'smaller" 6.5s like the Swede or 260, and a larger one like the '06 or WM.
 
Of course this is mostly a 'tempest in a teapot' as it appears that any bullet from about 120 to 150 is gonna be an excellent terminal performer. But there's nothing wrong with a little arithmetic 'exercise' between continents.
 
Paul
 
Here's an analysis I call Nominal Figure of Merit. It compares a rifle/cartidge/bullet against a "standard" and give a relative figure of merit. The "standard"is a 8.5 pound (3.9 kg) .30-06 firing a 150 grain spitzer that is capable of placing 5 shots within a circle whose area is 1.43 square inches (9.2 square cm). The variables used to calculate the FOM are; accuracy, mean KE, "flatness", recoil and "lethality". They are in order of 'importance'. In other words, as you go down the list of variables, the weight of each coefficient is less. I rank accuracy more important than mean KE, and so on. The FOM for the "standard" is 1000.
 
I used your 125 GS with the .49 BC and a MV of 3400. I assumed a rifle weigh of 4.32 kg, an elevation of 100 ft (about 30 m), an ambient temperature of 50*F (10*C), and accuracy of 9.2 square cm, and a charge of 50 grains of powder. The zero and max ranges can be set at any values you like, but for the FOM calculation they 'float' so that the maximum height above the line of sight is 3" and the minmum below the LOS is 3".
 
Paul
Be nicer than necessary.

CAfrica

Gitano,
 
I agree with most of what you said.  Now if you take the "sweetspot graph" and redo it using Momentum rather than Energy we may get some interesting results. As you say, energy uses the square of the velocity so therefore it is biased towards the lighter faster moving bullets.  I suspect that if you redo that graph using momentum, you will find that the heavier bullets will become the more likely "sweetspot" bullets.
 
Secondly, another factor in the equation is the "if the bullets behave the same" part.  That is the part where I prefer partitions and specifically the monolithics from a "penetration" point of view.  Less strong bullets loose a lot of weight at the point of impact, leaving a light remaining projectile that does not have sufficient momentum to (say) break a large shoulder bone. The monometal bullets ratain about 85 to 90% weight even at high velocity impacts and the partitions 75 to 80%.  A non partition, like a polymer tipped bullet, may loose as a lot more and on a close shot, where impact velocity is still high, it may fail to perform if it has to traverse much tissue to reach the vitals.
 
The 110gr GS is their heaviest bullet for this calibre (you used 125gr, maybe you picked up on where I said it has the same size as a 125gr lead core bullet).  Their other one is a 95gr.  I have a packet but have not tried it yet. I suspect that I might be able to get another 200ft/s or so out of it but that the lower BC will cause these two bullet to be about the same from the "sweetspot" point of view at 300yard ranges.
 
Thanks for the grpahs and information.
 
Regards.
 
 
C

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