Which is better out of a 20 inch barrel.  Which has better ballistics, knockdown, accuracy, etc.

Thank you,

Off hand, the 243 wssm will have much higher velocities.  They both make a great deer slayer.  Think of the 6.8 as a 270 winchester slowed down a little bit.  Everyone in the USA and Canada has probably hunted with a 270 winchester or with someone who uses one for deer.  The bigger debate about the 243 wssm (all wssm for this matter) is barrel life.   The 6.8 is not going to shoot as flat as a 243 wssm.  But remember you are comparing a 243 to a 270 caliber.  I'd go with a 6.8 for my ar upper, hopefully the gov't starts using it and someday we can have surplus ammo for it!

+1

I'm shopping for a 20" 6.8SPC upper for deer and elk in Colorado.

I'd go with the 6.8, I've heard that besides what winnie says they WSSM aren't doing well, and I don't think you need a round moving that fast to take a deer, as long as you place it well that's all that really matters, unless your hunting cape buffalo with a .22lr

If the 243WSSM can shoot a 95gr bullet at 3250fps from a 24" barrel, it will be around 3100fps from a 20" barrel.

The 6.8SPC will be a 100-115gr bullet at 2700-2850fps.

The barrel will last a lot longer on the 6.8, too.

-z

Could someone explain as to how the barrels wear out?

Every round fired down a rifle barrel contributes to erosion of the throat of the barrel.  This is the region of the barrel just forward of the chamber, where the highest temperature and pressures occur.  This metal is slowly eroded away by by hot combustion gases (and in some cases, blasted with yet-to-be-burned powder granules).   The higher the pressure and the temperature, and the more gas per shot, the faster this process occurs.

As the throat erodes, accuracy will suffer.  Eventually enough metal will be gone that headspace might be affected.    Top High-Power shooters usually get less than 5000 rounds through a 223 barrel before "it's done" for the kind of accuracy they need -- with some powder/load combinations, it's as low as 1000 rounds.

Generally, the higher the ratio of powder volume (ie, case volume) to bore area, or the higher the muzzle velocity, the faster the throat will erode.  When a cartridge has a higher volume :: bore ratio than standard cartridges like 308, it is considered to be "overbore" (or more overbore-- whatever).

243 WSSM is way more overbore than 223, and 223 is more overbore than 6.8SPC.

-z

how about the 25wssm

Quoted: Every round fired down a rifle barrel contributes to erosion of the throat of the barrel.  This is the region of the barrel just forward of the chamber, where the highest temperature and pressures occur.  This metal is slowly eroded away by by hot combustion gases (and in some cases, blasted with yet-to-be-burned powder granules).   The higher the pressure and the temperature, and the more gas per shot, the faster this process occurs. As the throat erodes, accuracy will suffer.  Eventually enough metal will be gone that headspace might be affected.    Top High-Power shooters usually get less than 5000 rounds through a 223 barrel before "it's done" for the kind of accuracy they need -- with some powder/load combinations, it's as low as 1000 rounds. Generally, the higher the ratio of powder volume (ie, case volume) to bore area, or the higher the muzzle velocity, the faster the throat will erode.  When a cartridge has a higher volume :: bore ratio than standard cartridges like 308, it is considered to be "overbore" (or more overbore-- whatever). 243 WSSM is way more overbore than 223, and 223 is more overbore than 6.8SPC. -z

If I'm understanding this correctly, it means a fat case with a small neck will eroding a throat faster than an equally fat case with a fatter neck, correct (in addition to other factors of course)?  So say for instance, a 7.62x39 should cause less throat erosion than 5.56 NATO?

Quoted: Quoted: Every round fired down a rifle barrel contributes to erosion of the throat of the barrel.  This is the region of the barrel just forward of the chamber, where the highest temperature and pressures occur.  This metal is slowly eroded away by by hot combustion gases (and in some cases, blasted with yet-to-be-burned powder granules).   The higher the pressure and the temperature, and the more gas per shot, the faster this process occurs. As the throat erodes, accuracy will suffer.  Eventually enough metal will be gone that headspace might be affected.    Top High-Power shooters usually get less than 5000 rounds through a 223 barrel before "it's done" for the kind of accuracy they need -- with some powder/load combinations, it's as low as 1000 rounds. Generally, the higher the ratio of powder volume (ie, case volume) to bore area, or the higher the muzzle velocity, the faster the throat will erode.  When a cartridge has a higher volume :: bore ratio than standard cartridges like 308, it is considered to be "overbore" (or more overbore-- whatever). 243 WSSM is way more overbore than 223, and 223 is more overbore than 6.8SPC. -z If I'm understanding this correctly, it means a fat case with a small neck will eroding a throat faster than an equally fat case with a fatter neck, correct (in addition to other factors of course)?  So say for instance, a 7.62x39 should cause less throat erosion than 5.56 NATO?

That's more or less true, but "fat" really has to be "high case volume".   In other words, you could neck  a 45ACP case down to 223, and it'd probably have less throat erosion than 223, even though it's fatter.

Yes, 7.62x39 ought to have less erosion than 6.8, less than 223.  7.62x39 is also lower pressure, and pressure is a big factor in throat erosion.    

Each additional round fired when the barrel is very hot has more effect than a round fired when the barrel is cold.

If you have the Stoney Point COAL gague, you can measure your throat erode over time.

-z

I have a 223wssm.  I do not expect it to last to long.  I have been getting well into the 4000's.  I have shot the 243wssm and like it a lot.  It is a flat shooting s.o.b.  There is almost no recoil and it will shoot lights out.  Short fat cases with sharp shoulders seem to be very accurate i.e. 6ppc, 6.5 Grendell.  
For hunting, I for a wssm, I would go with the 25wssm, I wish they made a 6.5wssm.  I think the 6.8 will have more dies, brass, and loads when all is said and done.  I would go with the 6.8.  Or if you are going with a bolt gun, inless you have a micro action, go with a 30wsm.  

Neither.

Go with what is known to work.

Quoted: how about the 25wssm

It is my understanding that this round is roughly the same as the 25-06, which is a great deer cartridge.  .243 is kind of a marginal deer round IMHO, but I have always been impressed with how the 25-06 knocks them down.

A buddy of mine just got a22",  .25 WSSM upper and is sooting 120 grain factory loads.  He said he's getting well under 1 MOA and about the same velocity as a 25-06.  For my kind of hunting I still like the.243 WSSM better.

Avoid the .243 bore size for deer. I will probably be flamed for this, but I had a 100+ gr, I can't remember which, Winchester silvertipped CXP2/lights skinned game bullet explode violently on the scapula of a yearling at 100m. It ruined a good quantity of meat. This was from a 20" barrel,  so it must have been several hundred fps slower than the WSSM bullet would go, and still it didtn hold up.

.25 WSSM would probably be a hell of a round for deer though. I still am waiting on the .25 WSM though.

Quoted: That's more or less true, but "fat" really has to be "high case volume".   In other words, you could neck  a 45ACP case down to 223, and it'd probably have less throat erosion than 223, even though it's fatter. -snip -z  Hey, Zak just gave me a great idea for my new deer round, the .224JAS

Reminds me of .224 BOZ. Where did that one go?

Keep in mind in many jurisdictions you will need an uber low mag - 3 or 5 max - or the game warden or ranger will come and ruin your day.  

A while back, some people were experimenting with a 20mm canon case shortened and necked down to 50 caliber.  It was called the 50 MAX or something like that - I don't remember.  With a slow 20mm powder, 750gr AMAX's blew up somewhere around 3300fps; with solids they got to 4000fps before the barrel's throat had totally eroded.

-z

Quoted: A while back, some people were experimenting with a 20mm canon case shortened and necked down to 50 caliber.  It was called the 50 MAX or something like that - I don't remember.  With a slow 20mm powder, 750gr AMAX's blew up somewhere around 3300fps; with solids they got to 4000fps before the barrel's throat had totally eroded. -z

In one of my books there was a .50 BMG necked to .338.

Quoted: Keep in mind in many jurisdictions you will need an uber low mag - 3 or 5 max - or the game warden or ranger will come and ruin your day.

For rifle, I believe in most states that have a limit, it's 5.

PRI lists 5 round mags.  I don't know if they are available now or not.  It should be easy to block a PRI 10 round mag to 5, or even use/block a 5 or 10 round 5.56 mag.

-z

Quoted:
Avoid the .243 bore size for deer. I will probably be flamed for this, but I had a 100+ gr, I can't remember which, Winchester silvertipped CXP2/lights skinned game bullet explode violently on the scapula of a yearling at 100m. It ruined a good quantity of meat.

Bullet selection and bullet placement.  The .243 Winchester or the .243 WSSM admitadly have poor "over the counter" bullet selection available, it doesn't mean the cartridge is poor for a particular animal.  I've shot many whitetail with the .223 Remington and have never tracked any of them nor have I thrown away any meat.  I hit the animal where I wanted to and I used a premium bullet.  I've seen many deer ruined by a.270 or 30-06 but it was purely bullet selection and bullet placement, not the cartridge.

Mardwell, it was a premium bullet, built for deer hunting. The shot was straight into the vitals. The bullet failed. I have no comfidence in lighth, high velocity bullets for big game after this. I switched to a 7x57 and made the next four kills with one shot each, with dramatic wounding and little meat damage.

I would still consider the .243 for long range shooting on light game, like antelope, or on animals I don't inted too eat. My kill may have wasted lots of meat, but he died exaclty where he stood.

well 243wssm uppers are out.. 6.8's really aren't...

but i'd want to go with 6.8

 Correct me if im wrong but there is not much difference from a 6.8 in a16 barrel vs a 20 inch barrel. The 6.8 was made to be shot through a carbine barrel. So if you went with 6.8 you might as well go with the lighter 16'' barrel. If what I said is true I would go with the 16'' for 6.8.

Quoted: well 243wssm uppers are out.. 6.8's really aren't...

www.model1sales.com/item-detail.cfm?ID=USO1068R&storeid=1&image=upoststd268r.gif

Model1Sales has them...

Quoted: Correct me if im wrong but there is not much difference from a 6.8 in a16 barrel vs a 20 inch barrel. The 6.8 was made to be shot through a carbine barrel. So if you went with 6.8 you might as well go with the lighter 16'' barrel. If what I said is true I would go with the 16'' for 6.8.

Expect 150-250fps difference from 16" to 20", depending on the load.

Winchester silver tip is NOT what I ment when I said "premium".  I'm talking Nosler partition.  You've heard of P.O. Akley haven't you.  He claimed that the .220 Swift was best caliber for the surest one-shot kill on whitetail that was available. (with premium bullets, of course)

Your're correct though, if you are going to buy "off the shelf" ammo, your way better off to stay away from the fast moving, small caliber, cartridges.

Quoted: Winchester silver tip is NOT what I ment when I said "premium".  I'm talking Nosler partition.  You've heard of P.O. Akley haven't you.  He claimed that the .220 Swift was best caliber for the surest one-shot kill on whitetail that was available. (with premium bullets, of course) Your're correct though, if you are going to buy "off the shelf" ammo, your way better off to stay away from the fast moving, small caliber, cartridges.

I don't know that the Partition was loaded at the factory at that time. Th bullet was some sort of polymer tipped wonder though.

[
I don't know that the Partition was loaded at the factory at that time. Th bullet was some sort of polymer tipped wonder though.

The poymer tiped bullets are designed for rapid expansion, generaly there is nothing to prevent them from coming apart.  The front of the partition is extremely light, it will expand even at great distance and low velocity (like the polymer tiped bullets).  But when you get to the partition, it stops expanding, retains it's mass and punches on through.

Quoted: [ I don't know that the Partition was loaded at the factory at that time. Th bullet was some sort of polymer tipped wonder though. The poymer tiped bullets are designed for rapid expansion, generaly there is nothing to prevent them from coming apart.  The front of the partition is extremely light, it will expand even at great distance and low velocity (like the polymer tiped bullets).  But when you get to the partition, it stops expanding, retains it's mass and punches on through.

Good to know. Neither I nor my dad knew anything about bullets at the time, we just used what the guy behind the counter liked.

Bullets for big-game are very difficult to design.  You have two major factors: 1) They need to expand, even at long range and low velocity, no mater where you hit the animal.  2) They need to be constructed so that if the bullet impact is at close range, high velocity, the bullet will not expand too rapidly, breaking apart and damaging meat, and perhaps not making a lethal wound channel.

Visualize the two extreme scenarios, both with the same caliber and bullet:

1) You take a shot at a whitetail that is standing about 400 yards away.  You have a .25-06 with 120 grain Remington Core-loc.  The bullet hits the animal between two ribs, just ahead of the diaphragm.  The bullet punches through the back of the lungs, never expands at all as it hasn't hit anything but hide and soft tissue.  The deer trots off, bleeding into it's chest cavity and eventually dying.  The bullet was constructed so that it would "hold up" under higher velocities or harder impacts.  

2) You are in the woods.  A large buck is in the brush only 30 yards away.  You can see his outline perfectly but he is in heavy brush.  You shoot, and he disappears.  You start looking around and find plenty of blood.  You track the wounded buck for ½ mile and when you find him, his front quarters are ruined.  The bullet, traveling at near muzzle velocity starts to hit brush and begins to "open up" and expand.  By the time the bullet strikes the deer, it's a whirling mass of lead and copper twice it's original diameter.  The bullet hits the deer directly on the front shoulder, breaks into thousands of tiny fragments.  The impact breaks the deers shoulder but there is nothing left of the bullet to continue through the shoulder and strike any vital area.

The Nosler partition takes care of both scenarios and everything in between.  The bullet is a soft point with a very thin skin.  About 2/3 of the way back through the bullet is a partition.  No matter what velocity or tissue it hits, it will expand.  If you take the second scenario, the partition would also have begun to "open up" or expand on the brush.  But when it hit the shoulder bone of the deer, the bullet would have "mushroomed" back to the partition, retaining 1/3 of it's mass and continued on into the deer's  vitals.  Nosler's motto for the partition is: Controlled expansion, Positive penetration.  That pretty well sums up what you need in a big-game bullet.  If you always knew how far away the game would be and exactly where you were going to hit them, you could probably do just fine with any bullet.

I'm sure this sound like a commercial but I've use the partitions for over 40 years and have yet to have a bad experience with them yet.  IMHO, worth the money!

Here's a link to a diagram of the Nosler partition:  http://www.nosler.com/partition.html

The 6.8 SPC is a .270 Win "slowed down a bit"...  what ballistics are you looking at?  A .270 Winchester (I do not know ballistics for a 115 gr bullet) will launch a 100 grain bullet over 3400 fps and a 130 gr over 3100 fps (out of a 22" barrel).

In Wisconsin we have an antlerless only early deer season at the end of October.  I'm going to give my .300 /221 Fireball a try with 150 grain Noslers at about 2000 fps.  I am worried about bullet expansion but deer do not go far with shattered front shoulders so I'll wait for a decent broadside shot.

Scot

THE 243 WSSM IS NOT A BARREL BURNER AS MANY OF YOU GUYS THINK.....just because it's name has wssm in it doesn't mean that it is....all it is is a fat shorten case with about 100-200fps increased in velocity...it's not that much.....compared to the 223wssm then it's a burner alright....700fps+ increased in velocity..

Oly's been testing the .243wssm upper and they've been through I think 4or5K rds without noticable erosions.

.243 I believe that. The .223 WSSM is absolutely brutal.

Many people tend to get the Nosler partition in too heavy of a bullet for the animal.  If you shoot the 25-06 and you would normaly shoot the 120 grain sp on a spacific aninmal, then going to the Nosler partition it is my practice to down-size one bullet catagory.  In the case above, I would go with the 100 grain Nosler partition.  You can't compare the partition, "apples to apples" with spitzers and soft points from other manufactures.  Same goes with the 6 mm bore.  If you would use the 100 grain on whitetail, jump down to the 85 grain partition and that will end the over penatration.  You get flatter shooting, less recoil, more shock power and the bullet will hold together just fine.

Just my .002

Why do you think you were over penetrating?  The partition is designed to expand and then retain about 1/3 of it's mass, continue through the animal creating a controlled wound channel.  Even if you down-size the bullet like I had talked about, the bullet will normally exit the animal.  The only whitetail that I ever shot where it didn't was on a deer that I shot going away ( I was desperate) I hit it near the base of the tail, it went right up the spine and ended up in the neck!  The partition, by design will penetrate more than a normal bullet but it will expand enough to be lethal.

I agree with you on the BC and down sizing the bullet.  I'm not normally hunting in a situation where BC is an issue.  If I were Elk hunting and thought I would be shooting longer ranges I would shoot the heavier bullet with the better BC.

I understand.  It has been nice discussing it with you though.  I'm new to this forum but it seems like no matter where you go you get people that love to push their opinion on you (an opinion most likely formed by reading someone else's post, not trigger time)  I tend to be old and opinionated but most of my opinions, correct or incorrect, are formed by experience, and I think your's are as well.