With all things being relatively equal whic cartridge should be more accurate at 300 yards. thanks

I wish you could do a search.  There have been a few threads....ahh..sh....iii.....I'll be right back with the search for ya.

www.ar15.com/forums/topic.html?b=1&f=5&t=142869&w=searchPop

this one talks about both rifle and caliber choice.
www.ar15.com/forums/topic.html?b=1&f=74&t=159575&w=searchPop

I personally would choose the .22-250 for 300yd shots and beyond.  The .223 is capable, but with more drop.  You end up compensating more, which leads to errors=poorer accuracy.  The .22-250 is flatter shooting, both calibers are capable of superb accuracy out of equal rigs.  I feel the max distance for hunting with the .223 is 300yds, and that's pushing it. JMHO

I think you need to look at rifles first.  Once you decide on action, the cartridge selection will follow. If you are talking  bolt action, my experience says a .22-250 M700 (REm) or m-11 (sav) is capable of .5MOA accuracy. If you talking semi- auto, good AR in .223 can shoot 1MOA, but .22-250 options are limited.  HTH, ZT

They fire the same bullet.

All things being equal I'll jump on the .22-250 - normally short fat cartidges are best for bench rest. Look at the fat 6mm and 7mm benchrest rounds for perfect examples.

The .22-250 does fling that bullet down the barrel a bit faster than the .223 rifle does. This means less bullet drop and less windage but not different accuracy, just less time for mother nature to work on the round on its trip to the target.

I went with the .22-250 for my varmint/benchrest rifle. They are nice but expensive to buy ammo for - reloading is just a tiny bit more expensive (more powder).

22-250, higer velocity = flatter bullet fight. I've shot ground hogs at 250yd, hear bullet "pop" about the same time rifle goes "bang".

I know its not on your list but check out the .243 Winchester.  I have been extremely impressed with this cartrige.  It uses a necked down .308 case.

I loaded some 60gr in a 243 H&R single shot about 3500fps and they shot a good 1/2 in. Just looking around on the net there are some loads approching 4000 in this cal.

Quoted: With all things being relatively equal whic cartridge should be more accurate at 300 yards. thanks

Accuracy: The ability to place a fired round into the same point of impact as previous rounds fired at the same aiming point.

Precision:  The ability to hit what you are aiming at, preferably with high levels of accuracy.

Given those parameters, I'd say this.  Both cartridges will shoot exceedingly well at tht range; whether you or the rifle or ammunition you have are capable of that accuracy is a big variable.  All things equal, the .22-250, by virtue of its flatter trajectory (muzzle velocities of 200-600  fps greater than a .223) with a given bullet weight and design is likely to give you an edge if you are shooting at an unknown distance and be slightly less suceptible to wind deflection.  

I've shot .223 varmint rifle extensively, and can head shoot a groundhog at 400 yards with 7 minutes of elevation using  55 grain nosler ballistic tip at 3200 fps.  My buddy, shooting a 50 grain NBT at 3800 fps, needs barely 5 moa elevation, and his gun shoot like a laser beam.

Shooter, I think you got accuracy and precision backwards.

I'd take the .22-250 since it shoots a little flatter and faster.  Both are very accurate cartridges.

Like my local gun shop owner says: 300 and less get the .223 and watch the groundhog explode. .22-250 recoils too much to see it. Above 300 you need to use the .22-250 anyway.

Quoted: Shooter, I think you got accuracy and precision backwards.

Yep.  I stand corrected and humbled.  Only about the 37th thing I've done backward today.

Quoted: .22-250 recoils too much to see it.

complete horse poop!!!!

If you or anyone else is interested I'm selling a Browning 1885 High Wall in .22-250.  It's new but I have no box.  Leupy 1 inch rings inc.

750.00 cash (paypal +3%) shipped to your FFL

For shooting at 300 yards, I would select the .22-300, not the .22-250.

The .22-250 has recoil - yeah whatever!

My benchrest/varmint weighs in at about 12-13 pounds ... it hardly moves at all but due to its 36x power scope the target does jump from the scope. Set at a lower power like 24x or so the target is perfectly viewable.

If you want a super accurate hot rod go with the 22-250 ackley Improved. Much better than a regular 22-250 and you can shoot regular 22-250 ammo if you need to, matter of fact that is how you fire form the brass.

Have you guys seen any of the info on the new Winchester super short mags... .223 WSSM and the .243 WSSM.  .223 WSSM pushing 3800 fps with 52 gr slugs.  .243 WSSM pushing 4000 with 55 gr slugs.  One of those will be my next varmit rifle.  Right now you can only get them in the Win mod 70 or the Browing A Bolt.  Lets see, my birthday is in Feb... hmmm