6.5 vs .257 cartridge question

[Bill Norris]

After powder run up and seat depth check I shot this 5-shot gp. @ 100 yds. measured .071. Shot another 5-shot gp. a couple of days later at 100 yds. kind of hurrying and gp. was .222 so I think it's ready to check at distances now.

 

[Bill Norris]

These guys are planning to run the 25 X 47 Lapua in their next NRL Team season.

 

[JEFFPPC]

I thought it was Smoothness is Speed.

Could be, I was never Fast or Smooth. But I could run you into the ground.

 

[B23]

For those that need/want to shoot factory ammo I see the 25 Creedmoor being a very popular choice for many. Slightly less recoil and slightly better ballistics with the 25 Creedmoor compared to the 6.5 Creedmoor so kind of a win win deal not to mention a good excuse to buy/build a new rifle.

 

[ISS]

I usually jump from 223 to my 257 Banshee (=257-300WM), then to my 300WM Eliseo or my pre-64 M70 in 300 H&H. For the next step up I am packing for that last desired trip to Africa.
I do envy you guys that can afford to shoot factory ammunition...

Rich

 

[Kurz]

And just so we can get a little historical information:


https://www.cartridgecollector.net/cartridge/257-condor/

Originally developed in 1946, Dr Ramon Somavia.


Norma 7x61 Sharpe and Hart on the left; Norma .257 Condor on the right.

Dimension drawing:

 

[Bowling Green]

I had a 26" Ruger #1 in 25-06 using 90gr Absolute Hammers at 3600+ at the barrel. VERY efficient on deer with very little bloodshot meat.

I plan on doing a 25-284 and am hoping for 3700+

I actually have a 25-284 and have some load data that I got from emailing Vihtavouri that I could share

 

[Wild Bill IV]

What is the difference? I mean really. Can some one tell me.
Lets take the 30-06
Now lets stick a .257 bullet in it.
The 25-06 is way more snappy then the 30-06
I do prefer the 25-06 over the 30-06 in terms of precision. Ive just had an easier time tuning 25-06 loads over 30-06. That could be because of Bullet B.C...i dont know because ive never once paid attention to those numbers.
Now what happens with a 6.5 bullet? I dont know because ive never shot one, and i dont follow numbers.
I dont know of any bullet that has a larger selection of on the market like the diverse. 308
So now were back to the 30-06..
If i was shooting antelope in Texas id want a 25-06, if im after that trophy buck, its the 30-30, or 30-06..only because i have experience with those cartridge and know what they can do.
So where does the 6.5-06 fit into all this? What would you use it for..sound like its on the edge of a a barrel burner with not much to gain.
Im just curious
Thank you

I questioned this years ago! 25-06 vs 6.5-06!!!!
I have a BS in Industrial Physics (Robotics enthusiasts during 386/486 microprocessor computer age).
Fundamentally, a body (bullet in flight) possesses momentum, not energy!
For hunters, down range energy is somewhat misleading!!!
Down range ballistics is more of a collision problem (fundamentally solved through conservation of momentum, not conservation of energy)!!!
The OGW lethality formula is based more on momentum than energy which Bryan Litz mentioned in one of his books!!!
OGW (Optimum Game Weight in lbs) = V^3 * M^2 * (1.5x10^-12) for Big Game!
Where V is the down range velocity (f/s) and M is the bullet weight (grains)!!!!!!!!!
Replace the 1.5x10^-12 with (5.0x10^-13) for Varmint hunting!!!
The OGW can be mathematically rewritten for looking at energy based [(M*V^2)^2]/V or momentum based [(M*V)^2]*V!!! Either way, we end up with V cubed x M squared!!!! Looking at by word definition, the momentum squared times the velocity vs the energy squared divided by the velocity!!! I prefer the momentum part of the formula since a body possesses momentum!!!!

Let examine a 25-06 at 2900f/s (MV), 117grain SBT SGK (BC: 403 between 1800-2000f/s) at 500yd (v=1864f/s, E=980ft-lbs). OGW = 59.1lbs!!

For the 6.5-06 at 2800f/s (MV), 140grain SBT SGK (BC: 480 at, or less than 2000f/s) at 500yd (v=1942f/s, E=1172ft-lbs). OGW = 95.7lbs!!!

For the hunters looking at DRE (Down Range Energy) the 6.5-06 has 30% more Energy than the 25-06 at 500yds with the 2 above scenarios!!! But, the 6.5-06 has 62% more Lethality than the 25-06 at 500yds!!!

Now, as Bill Norris is finding out, the 25-06 is an over bore cartridge (PO Ackley stated) and the 25x47 can keep up, and looking like it can beat the 25-06.!!!
In PO Ackley's books, the 6.5-06 is at peak optimum bore!!!! He stated, the 6-5-06AI is over bore and is a waste of time and money in wide shoulder, blown out body taper improved Wildcats!!!! VERY LITTLE GAIN IN VELOCITY VS ADDED POWDER CAPACITY!!!

Plus, the 6.5 bullet will have more rotational inertia than the 25 bullets!!! And the rotational torque will be much higher, thus bucking the wind better since the rotational center of mass has moved outward farther from the center of rotation!!!

This is the physical/mathematical facts than hunters must understand!!!!
HOWEVER, hunters ethics is another subject!!! The ethical hunter has to know his, and the rifles capability when stepping into the field!!!

I have a Custom 25-06 and have shot deer clear out to 574yds (10pt whitetail buck, one shot heart/lung kill)!!! The barrel is starting to go out!!!! I'm going to replace the barrel and rechambered in 6.5-06!!! With the 6.5-06, I might be able to roll the deer, instead of dropping them the the 25-06 does now!!!!

 

[Idaho-Lefty]

I thought it was Smoothness is Speed.

6.5 Caliber Bullets ARE Teflon coated to,.. "Buck the Wind",.. better than,.. .25 cal's ,.
Sorry, I couldn't help myself,.. LOL !
As a grown man, I went,.. kicking and Screaming with,.. the 6.5 Creedmoor about, 5 years ago.
Dam thing, IS, a Ton of Fun, on Steel Plates way, the fudge,.. out there !
Pew,... Ting !

 

[Wild Bill IV]

Wow!!!
Knowing physic formulas and math manipulations of formulas, the natural number "e" is used a lot!!! Looking at the OGW formula, and using momentum only, I came up with the formula OGWe=(MV^e)/(e x 10^12)!!!!!

The numbers fell into what I've experienced shooting the 25-06 and 7mm-08 at big game!!!

Using the 25-06 load in #48 and adding my 7-08 load of 2700f/s (MV) using a 160gr SBT SGK bullet with 472BC between 1600-2300f/s with V=1832f/s at 500yd!
25-06 at 500yd, OGWe=119.6lbs!!!!
7-08 at 500yd, OGWe=267.1lbs!!!! 123% increase in lethality!!!
And the hits on antelope close to 500yds with 25-06 and 7-08 reflected the 2x differences!!!
This explains the violent rolling (putting him on his back) of a +300lb buck at 275yd with the 7-08!!!

Now, using the OGWe for the 6.5-06 example above, OGWe=217.7!!!! 82% higher than the 25-06 and 22.7% lower than the 7-08 all at 500yd impacts!!!!

I'm still going to rebarrel the 25-06 custom rifle into a 6.5-06!!! Still have a bunch of 25-06 and 30-06 brass!!!!

 

[moondog]

I thought about doing a 25x47, I've got 1000 pieces of Virgin Lapua Brass. I love my 6.5x47. Low recoil, super accurate, and great Barrel life. Also have a 6.5x55GWI that I've been working with a lot lately. 150 SMKs at 2980ish is an easy Mile load. 130s and 140s at 2920 are just stupid accurate. I think I'm sticking with the 6.5.

 

[Bill Norris]

Wild Bill IV said​

Now, as Bill Norris is finding out, the 25-06 is an over bore cartridge (PO Ackley stated) and the 25x47 can keep up, and looking like it can beat the 25-06.!!!

This new reamer that Zack Donovant - ODCR has designed is giving the 25 X 47 a huge blessing with a tad more juice under the bullet. Can't wait to get it out to 600 yds. and beyond once the heat backs off a little. I have been to 3000 FPS with the heavies but backed down to better tune @ 2950 ish FPS per numbers on the Garmin.

 

[choprzrul]

I'm gonna make sure I'm grasping this correctly. Using Nosler load data for 100gr Ballistic Tip bullets in both the 25-06 and the 6.5-06 A-Square, max loads and associated BC:

25-06: 3361 fps, .393 G1
6.5-06: 3547 fps, .350 G1

25-06 ballistic table:


6.5-06 ballistic table:


2206 -vs- 2219 fps
1080 -vs- 1094 ft lbs

Someone is going to have to help me understand how the 6.5-06 has 30% more energy at 500 yards compared to the 25-06??

.

 

[Wild Bill IV]

I'm gonna make sure I'm grasping this correctly. Using Nosler load data for 100gr Ballistic Tip bullets in both the 25-06 and the 6.5-06 A-Square, max loads and associated BC:

25-06: 3361 fps, .393 G1
6.5-06: 3547 fps, .350 G1

25-06 ballistic table:
View attachment 1684014

6.5-06 ballistic table:
View attachment 1684015

2206 -vs- 2219 fps
1080 -vs- 1094 ft lbs

Someone is going to have to help me understand how the 6.5-06 has 30% more energy at 500 yards compared to the 25-06??

.

Now try picking a heavy bullet (115-120grain, the DEATH ALLEY choice for the most common 1:10 twist in factory hunting rifles) for the 25-06 and find its muzzle velocity!!
Then pick the same type of bullet in 6.5 that will have the same muzzle velocity with the same BC!!!
With the same muzzle velocities, and the same BC, the two bullets will have the same: trajectory; time of flight for 500 yds; and down range velocities at 500yd!!
Therefore, the larger bore bullet will be heavier!!
Crunching the numbers for E = 1/2*m*v^2!!!
The v squared components will be the same for both bullets at 500yds!!! The 1/2 is a constant!!
Therefore, through mathematical deduction, the ∆E% (DELTA or difference of energy in percentage) will be directly proportional (equal) to the ∆m% (DELTA or difference of mass of the bullets in percentage)!!
I picked the Sierra Gamekings with the Spitzer Boat tails because most of their SBT bullets increase as the velocity decreases down range!! Even Bryan Litz mentioned this briefly in one of his books!!! He didn't go into details!!! Wonder why??????
The Sierra SBT GKs are awesome at long distance!!! When load development is done right in a tuned rifle, they can hit an antelope heart (full body target) at 600 with ease, on fairly calm days, in the 25-06 and the 7mm-08 that I own(ed)!!! My custom 25-06 is going to become a 6.5-06 for increased lethality!!

 

[choprzrul]

How do you get 2 bullets of different diameter, but the same weight, to have the same BC? The smaller diameter bullet will be inclined to have a sleeker profile and likely a higher BC, correct? If you then give them the same muzzle velocity, the sleeker, higher BC bullet will retain more velocity down range.

The only way I can see to make this work having the same muzzle velocity, BC, and weight is for the larger diameter bullet to be of a different design/shape to get the BC numbers to match......which then is comparing apples to oranges.

 

[bobcat93]

I was watching a recent video on the test and use of the 30-06 on body armor, on the battlefield.
It was old WWl or WWll
It was when the 308win was being considered.
They said most men didnt want to give up the 30-06 because it would blow right through body armor out to 800yrds as seen on the feild of battle not a laboratory.
The 308 win struggled at 400yrd.
Im not looking to blow thru body armor.
But the statement does clearly point out the usefulness of same caliber bullet, different power levels can come in very useful say in hunting.
From deer at 100, and perhaps elk at 350 .
I thought it was interesting information

 

[ebb]

Something sinister may be going on, all this talk about 25s and Alex posts, but not once did he mention the 25 Killer Klutz that he has developed. Alex, Tom and Ol Roy and an attempt to break this years records with new 100+ lb ziricote stock, chambered in proprietary 25 Killer Klutz, and driven by Tom. You heard it here first at the outa touch curmudgeon news network.

 

[Owens85]

Something sinister may be going on, all this talk about 25s and Alex posts, but not once did he mention the 25 Killer Klutz that he has developed. Alex, Tom and Ol Roy and an attempt to break this years records with new 100+ lb ziricote stock, chambered in proprietary 25 Killer Klutz, and driven by Tom. You heard it here first at the outa touch curmudgeon news network.

If your talking about Toms HG I believe that was a 300 wsm.

 

[choprzrul]

I was watching a recent video on the test and use of the 30-06 on body armor, on the battlefield.
It was old WWl or WWll
It was when the 308win was being considered.
They said most men didnt want to give up the 30-06 because it would blow right through body armor out to 800yrds as seen on the feild of battle not a laboratory.
The 308 win struggled at 400yrd.
Im not looking to blow thru body armor.
But the statement does clearly point out the usefulness of same caliber bullet, different power levels can come in very useful say in hunting.
From deer at 100, and perhaps elk at 350 .
I thought it was interesting information

I completely agree. More power is gonna win.

However, when you have the same bullet weight, design, and velocity, the smaller diameter bullet is going to have a higher BC and more retained velocity down range.

Changing variables is always going to give different results. Bigger diameter, heavier weight, and more velocity will absolutely hit harder down range.

 

[ebb]

Yes it was, but in the discussion Alex mentioned a 25 caliber chambering he is building, and the possibility of it doing well a Deep Creek, with some of the new long range bullets that are being made now.