i have found a 6.5mm 140-grain spire point bullet at 2,600 fps to be the "perfect" deer killer for me. this happened to be a swede recipe with remington core-lokt bullet. i no longer have a swede and have killed many deer with many other chamberings. but that recipe seemed to do the job with so little fuss at ranges from 30 feet to 200 yards and more.

now then, here is my question: is there a simple ratio that would express this recipe for efficiency in other calibers? example: at what velocity and weight would a .277 caliber bullet of equivalent construction do the same efficient job?

i don't think this formula can be reduced to foot pounds of energy, which would be real easy to figure for any caliber, because it does not take into account trajectory. the swede load just seems to have a certain savoir-de-faire.

if there is no ratio or formula, perhaps some of you guys could mention some savoir-de-faire loads for your favorite chamberings. i'm looking to buy/build something swede-ish. was hankering for a medium bore but now i'm not so sure.

many thanks for any interest.

A 270, 140 grain bullet traveling at same velocity, will give the exact same Foot pounds of energy.

There is no tried and true formula for what you want. Basically any 140 bullet traveling at 2600 fps will give you the same muzzle energy (however, downrange energy will be a totally different story).

In addition, terminal performance of a bullet is not just designated by it's speed, or it's construction.

My favorite .270 load is:
Bullet: Sierra 140 Grain Hollow Point Boat Tail
Powder: 53.1 grains of IMR-4350
Primer: Winchester WLR
Case: Winchester
Firearm: Winchester 70
Velocity: 2944 FPS @ 15' from muzzle

Look for the bullet that has the same ballistic coefficient and sectional density , 150gr 277, and drive it at the same velocity.

hey mete:

i'm thinking that would give the same basic trajectory, wouldn't it? within reason?

so BC would be a part of the formula. i guess sectional density would be a big part of terminal performance, all other things being equal, for any bullet designed for deer-size game.

ok.

i'm thinking recoil foot pounds should be part of it, too, from a shootability standpoint, which means rifle weight has to figure into the "formula."

grasping at straws here, i think, after a point.

6.5 140 gr verses .277 140gr
Zeroed in at 100 yards, it would be my guess, that the trajectory out at 300 yards would be less than an inch, and foot pounds of energy would be less than 40 to 50 fpe difference.

[ 02-20-2003, 20:50: Message edited by: Marsh Mule ]

crunched some recoil numbers based on memory and semi-educated guesses for a 7 pound rig. i picked 7 pounds because that's what i'd like to shoot for on my next rifle, even if it's iron-sighted rather than scoped. it's useful for comparison's sake, anyway.

.257 bob, 120-grain bullet, 2,600 fps, 50 (?) gr. powder, 14 foot pounds of recoil

6.5x55/.260 rem, 140-gr bullet, 2,600 fps, 46 gr powder, 15 foot pounds of recoil

.270 win, 150-grain bullet, 2,600 fps, 52 gr powder, 18 foot pounds of recoil

.308 win, 180-grain bullet, 2,600 fps, 45 (?) gr powder, 21 foot pounds of recoil

8x57, 200-grain bullet, 2,600 fps, 50 gr powder, 26 foot pounds of recoil

.338-'06, 225-grain bullet, 2,600 fps, 60 (?) gr powder, 32 foot pounds of recoil

recoil friendliness goes way down as bore size goes up. what y'all think?

fish280-

The recoil goes up because the bullet weight goes up. The powder charge stays relatively constant (except 'till you get to the 338/06). If it were possible to get the same speed out of the same weight bullets with comparable charge weights, in each different bore size, they would all recoil "about" the same in like weight guns.

B Stephenson

My Girlfriend bless her heart gave me Sierra�s 5th Edition Manual for my birthday. (thanks Dino) If you want to get good information on BC this seems to be the place to start. I never really worried much about BC because I have never shot a Rifle any further then 200 yards. I was much more concerned with whether I shot good groups then BC. After reading the manual I decided to try and put some of what I learned to the test. In response to Mr. Riccardelli I think he may have been exposed to a 1936 through the 1960s version of calculating BC which Sierra said was not very accurate. They now use three methods to calculate BC all of which require test firing. One uses muzzle velocity and final velocity, one uses muzzle velocity and time of flight and one uses the doppler radar method. All take into account air pressure, temperature, altitude, humidity, wind direction both horizontal and vertical and elevation angle. They then use their ballistic program to calculate the only possible BC that can fit the given parameters. They give an example of how the infinity program can allow a hunter to sight in at one set of variables type in the variables where they plan to hunt and have the trajectory calculated at the new set. The doppler radar method was used at the Yuma Proving Ground with two match king bullets. This method allows you to see the BC all the way down the path of the bullet from the muzzle to about 700 FPS. The reason Sierra gives three BC�s is because it changes with velocity. They still do give all the BC�s for their bullets on their web sight. When the bullet leaves the muzzle it takes 50 yards or so to stabilize, once it does the BC goes up and more or less stays the same until it hits 1600 FPS (transonic) when it quickly drops to its lowest practical point at just above the speed of sound. As soon as it goes below the speed of sound it jumps to its highest point at 1000 FPS and gradually drops to its worst point after that. My match .22 rimfire shells are all subsonic. Now I know why. I shoot my 300 whisper at 1250 FPS and now plan to drop it to 1050 FPS. The infinity program says my wind drift with a 3 o�clock 20 MPH wind will actually be about 33% less with the lower velocity 1050 FPS load. Will it? Who knows? Is Sierra full of BS? Maybe, but if you want something with a hypothetical number look at foot pounds.

Formulas have been made up for the effect of a bullet on game. At the Handloader Dave Scovill had one but gave up on it.

That's why all these words are here www.mindspring.com/~ulfhere/ballistics/wounding.html

For a general rule this old saying is as good as any and maybe better. "If you don't know what big game rifle to get then get a 30/06, load the 180 gr bullet and sight it in for 200 yards. This is all that you need to know about big game rifles"

Good link, Don... thanks!

A lot of the 6.5 bullets are designed to expand better at the lower velocities (2000 fps ot 2400 fps).

I'm not the "great white hunter" it would take to make useful observations as to the reasons for the killing power of the Swede, but those who have routinely used this cartridge on much of the world's game have always assigned an almost "super-ballistic" quality to the effectiveness of the cartridge.

It seems to be a perfect balance of several things. You'll likely best duplicate those ballistics with a .260 Rem, but I believe the Swede to be the better cartridge yet...

Dan

Green,

This bullet diameter, sectional density, velocity, construction and shape thing is of constant interest. We note that there is little activity on shotgun forums.

There are so many variables when a bullet hits something that there is no exact answer.

A bigger faster bullet will be "overkill" however it will cover a lot of variables.

These comments do not apply to the 6.5 Swede but it seems adequate for deer.

The trend over the last 50 years however is been to higher velocity and now better and better bullets. This has to be the future. The same old cartridges will fire these new bullets as of today as there have been no significant improvements in propellants.

I think the formula is simple....put a decent bullet in the right spot.... good things happen.

Fish280 sounds like you are hitting on the same thing many people describe as "perfomance out of proportion to its paper ballistics". Some of the classics like the 257 Roberts, 6.5 Swede and 7mm Mauser are at the top of the list. I now hunt wild boar with a 25-06. When you take in account its too short barrel it has velocity on par with the 250 Savage or 257 Roberts but kills like my 30-06 or 338 WM. I thought it was a magical caliber but now know it is due to my confidence and ability due to lack of recoil that allows me to shoot it so well. If your looking for a quantifiable answer I would look at cartridges that have mild recoil (14 lbs.) and high B.C.

My 270 with 130 grain Noslers works great on small game and have no problems with big game Kudu, Gemsbok