speed, power and accuracy

[model 70]

can someone clear up a few things?

why is it that the .220 swift surpasses the .22-250 in speed (and power?) when shooting the exact same wieght .22 cal bullets?

why do you hear about most long range shooters using the .308win instead of the 30/06 yet both can fire the exact same bullet with the '06 using more powder?

doesn't a bigger powder charge push the bullet faster and more accurately?

[rem 700]

The 220 swift may use the same type of bullet such as a 40 grain BST as the 22-250 with a 40 grain BST, but the ballistic co-efficient of these bullets are different by a tiny fraction, so the 220 eventually surpasses the 22-250 due to its more aerodynamic bullet properties.

[bulletpusher]

model 70

The 220 Swift and the 22-250 can shoot the exact same bullit, same diameter, same length, same weight, same aerodynamic properties. The Swift holds more powder in the case than the 22-250. Thats how it gets more speed. They are like two peas in a pod as far as performance. The differences in performance are so small that once the trigger is pulled you and your target can't tell the difference. If you look at modern loading manuals, and use modern powders you will get almost the same result. Its just that because the Swift case (taken from the 6mm Navy cartrige) and the 22-250 (taken from the 250-3000 Savage cartrige) do not hold the same amount of powder. Nuff said.

The 308 and the 30-06 fall under the same rules. The 06 case is longer than the 308 case and can hold more powder. Because of the case efficentcy of the 308 cartridge it will do almost vertually the same as the 06 cartridge.

The 308 and other small/short cases are the in thing for long range target shooting and because the 308 was the most recent 30 cal. military cartridge it is more sexy.

The 30-06 was winning compititions and 1000 yard matches before the 308 was even a dream in its designers head.

The 30-06 works better than the 308 with the same bullet weights but the differences are minimumal, that is untill you get into the heaver bullets. That is where the 30-06 pushes further ahead of the 308.

Just as with the Swith and 22-250 the more powder you put behind a bullet the faster it will go and the flatter it will fly. Just remember that all things have a limit. You can't make the 30-06 into a 300 H&H, 300 Winchester or 300 Weatherby, just by putting more powder in the case.

Hope this helps.
Bulletpusher "BBRSSC #1"

[rem 700]

[QUOTE]Originally posted by bulletpusher
model 70

The 220 Swift and the 22-250 can shoot the exact same bullit, same diameter, same length, same weight, same aerodynamic properties.

Bulletpusher "BBRSSC #1" [/QUOTE

www.winchester.com You can see the differences in the muzzle velocity and the downrange velocity changes in these 2 cartridges here. You'll notice that the 22-250 has a higher muzzle velocity than the 220 swift, but the 220 swift has a higher ballistic co-efficient on its bullet, meaning it's more streamlined, so when downrange, the 220 swift will eventually have the speed advantage.

[Tater]

I'm not sure if this is true or not but I remember reading that the angle of the shoulder has a lot to do with the efficiency of the power burn. I think this is why the short mags can do so much with less powder. I am by not means an expert so if I'm wrong please let me know.

[L. Cooper]

The .220 Swift and the .22-250 Remington can shoot the same bullets. IF you shoot the same bullet from a particular manufacturer in both guns with powder charges maxed out for each cartridge, then the faster muzzle velocity of the Swift will be carried for the full range of the bullet's travel.

For the physicists out there, the velocity difference between them will decrease as distance increases because the faster bullet will slow more quickly than the slower one due to more friction with air as a result of its initially higher speed. But the faster one will always be faster at any given distance from the muzzle.

Now, shoot two different bullets of the same weight in both guns, or two bullets of different weight, and you will find differences in down range performance.

But the .220 Swift and the .22-250 are made to shoot the same bullets, as are the .308 and the .30-06 and all the various .300 Magnums for that matter. Case volume (and subsequent powder volume with subsequent larger volumes of gasses to drive the bullets) is what creates different performance levels within the same caliber.

And as bulletpusher says, you can't make a case of one volume push a bullet as fast as a case with a larger volume. Hence the 7mm-08, 7x57, 280 Rem., 7mm Rem Mag, 7mm Weatherby, 7mm Ultra-Mag and so on, all have their zealous followers. But they all shoot the same bullets.

[bulletpusher]

Rem 700,

The 220 Swift and the 22-250 pushing the same bullet (and I meen the EXACTLY same bullet will have the exact same ballistic co-efficient. The only way for the BC to be different is to use two (2) different bullet designs.

If these bullets are the same (i.e., same dia. weight, length & design) (an example would be two 55 grn ballistic tip bullets for that caliber) then the BC will be exactly the same.

If for example you are comparing a Nosler Ballistic Tip bullet with a Sierra BTHP Match then the BC will be different.

My last words on the matter.
Bulletpusher "BBRSSC #1"

[Rocky Raab]

The difference between the two pairs of cartridges (220 vs 22-250 and 308 vs 30-06) are simple: case volume and working pressure.

The 22-250 has a case capacity of 45 grains of water, and a working maximum pressure of 65,000 psi.

The 220 Swift holds 46 grains of water and a maximum pressure of 54,000 CUP.

The comparison may seem skewed in pressure, but that's the difference between a psi measurement and a CUP measurement. In reality, both rounds are as alike as peas in a pod.

With maximum pressure loads, the 22-250 will boost a 50-gr bullet to about 3850 fps. With the exact same bullet (with the same BC), the 220 Swift will get 4000 fps. Believe me when I say that there isn't a spit of difference between 3850 and 4000 fps at the muzzle. More importantly, those numbers might be reversed with two different rifles, with the Swift being a titch slower.

The difference between the 308 and the 30-06 is more dramatic in physical measurements. The 308 holds 56.0 of water while the 30-06 holds 66.0. Ten grains makes a big difference - except for pressure. Due to the age of some rifles (a century), the 30-06 is now loaded to a maximum of 55,000 psi, while the newer 308 (and its stronger rifles) can be loaded to 60,000. At peak pressure, with the same bullets, the two are also identical in performance. The 308 will get a bit over 2800 fps with a 150-gr bullet, and the 30-06 will get a bit over 2900. No real difference.

The reason that many target shooters use the 308 instead of the 30-06 (at ranges of 600 meters and less) is not velocity, but recoil. The 308 gets its performance with as much as ten grains less powder, so it has significantly less recoil than the 30-06. Less recoil= less flinching=higher scores. It's that simple.

(At much longer ranges, the edge goes to bullets with extremely high BC, and smaller cases can't launch them fast enough to take advantage of the BC. So 1,000-yard shooters often use mega-magnum cartridges to launch very heavy, very long, very streamlined bullets - and have to suffer the recoil.)

[MarkL]

I've read that the .308 is demonstrably more accurate than the 30-06 due to having a shorter powder column. In theory, having a higher percentage of the powder close to the primer leads to more consistent ignition (or something). Just don't ask me (or probably anyone else) to prove it!

[rem 700]

Originally posted by bulletpusher
Rem 700,

The 220 Swift and the 22-250 pushing the same bullet (and I meen the EXACTLY same bullet will have the exact same ballistic co-efficient. The only way for the BC to be different is to use two (2) different bullet designs.

If these bullets are the same (i.e., same dia. weight, length & design) (an example would be two 55 grn ballistic tip bullets for that caliber) then the BC will be exactly the same.

If for example you are comparing a Nosler Ballistic Tip bullet with a Sierra BTHP Match then the BC will be different.

My last words on the matter.
Bulletpusher "BBRSSC #1"

Winchester 220 swift 40 grain BST: BC: .221

Winchester 22-250 Remington 40 grain BST: BC: .214

Sorry, but they are different. If you handloaded with the same bullets, or bought from certain manufacturers(Hornady I believe does this), that's a different story.

[Rocky Raab]

It's not commonly known, but BC can and does vary - even with the same bullet.

Slight variations in shape, weight or concentricity can change the BC of a bullet between lots. So can the effect of the gun's rifling! Bullets that get deeper or more pronounced grooves cut into them by the rifling will have a slightly greater drag.

So it's not surprising that the tested BC of ostensibly identical bullets can vary by a small amount.

[Jack]

"It's not commonly known, but BC can and does vary - even with the same bullet."
Yup, and even the velocity can change B.C, according to Sierra. If you look at Sierra B.C. data, they'll give you a different B.C. for different velocity ranges.

[PJgunner]

Bulletpusher said, "The 30-06 works better than the 308 with the same bullet weights but the differences are minimumal, that is untill you get into the heaver bullets. That is where the 30-06 pushes further ahead of the 308."

Permit me to disagree slightly with that statement. I keep hearing that old line that the .308 cannot do well with heavier bullets, thus giving the 30-06 an advantage.
Now this has to be just a hair on the apples and oranges side of things, only because there are no factory loaded 220 gr. bullets in .308 Winchester.
Now Winchester advertises 2400 FPS with a 220 gr. bullet in 30-06. With judicious handloading, I have safely loaded a 22" barreled .308 winchester with 220 gr. Sierra round nosed bullets to 2260 FPS and have one load giving 2300 FPS using W-760 powder. If I could find a box of factory Winchester 220 gr. loads for the 30-06, I'd run them over the chronograph. I'd be willing to bet, that based on velocity testing of Winchester's 180 gr. Silvertips, that the 220's would be closer to what I was getting from the 220 gr. 308 loads.
Assuming that Winchester's 220 gr. load does in reality give 2400 FPS, I don't see where 100 FPS less from a .308 is any real disadvantage.
Be advised that I worked up the .308 loads in a Winchester Model 70 with a 1 in 12" twist. Using another brand of rifle having a 1 in 10" twist will most likely cause pressures to be higher.
FWIW, accuracy was fantastic with groups in the .375" range at 100 yards from a sporter in a Ramline stock. Scope was set at 9X for the tests.
Try it if you want, but data is scarce for that heavy a bullet.
Paul B.

[California Hunter]

I love these questions, and the answers (and arguments) they elicit. First, of course, there is the technical side of the question and Rocky nailed it. While there are techical differences in case capacity which leads to both theoretical and actual performance differences, they are slight as to be unseen in the field or on the range.

Secondly, there is the practical side. The truth of the matter is, from a users standpoint, the difference between the cartriges discussed is virtually zero in terms of accuracy and power. In both cases, 220 vs 22-250 and .308 vs 30-06 the differences are so small as to be absolutely unnoticed by either the shooter; or the game taken by any of the calibres currently compared.

As a side, I recomend reading this article from another site. It is one of the best pratical answers I have seen to a whole series of questions regarding cartrige selection, bullet weight, velocity, sighting recomendations etc. http://www.kifaru.net/posimag.htm

Isn't it great that we, as a hunting and shooting group, can have such strong opinions on matters so small:--)

[Evan03]

yeah and as our opions grow and change we begin to buy more rifles.

im now a porud owner of both 220swift and 22/250.
i agree they shoot the same even facotry ammo is loaded to almost the same velocity specs in both calibers useing identical bullets