This may have been discussed all ready, so I apologize in advance.
What is the maximum effective Range for the 6.8
doubleajaybrock
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JJ, could you please clarify for everyone what you are asking about specifically, when you say effective range?
I hate seeing a thread continue in confusion when the question is not clear...:a43:
There are so many knowledgeable people on this site with years of physical experience with this caliber (not just theoretical couch commandos with Call of Duty training) that if you are truly looking for an answer, you are going to find it here.
BTW- I can stop iron sheep & pigs constantly up to 600 yards with factory SSA commercial ammo out of a 16" Noveske.
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It's a barrel, bolt, and magazine change (compared to 5.56), not just a follower in the standard GI mags...
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That's very true, and the Major made that point in his monograph.
Note to Rutgers95, et. al. : I have a PDF file of the monograph. Can I upload it here anywhere to make it available to everyone? It's about 1.2 meg in size.
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Yeah. As I said, change out the upper, and a magazine fix.
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It never gets brought up, but what about the rear sight elevation? Especially if we are discussing USMC 500 yd training, there might be a few more clicks needed on the elevation ring to drop them into black.
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Sorry, I'm partly agreeing with you, and partly not! Changing out the follower on standard mags is not going to make a 5.56 mag a 6.8 mag, which is how I take what you typed...Yeah. As I said, change out the upper, and a magazine fix.
"A good part of the piece was also about how to remedy this situation (all in reference to the typical engagement in Afghanistan being beyond the 200 yard effective range of the 5.56). One idea he pushed quite hard was retrofitting current M16 rifles with new A4 type uppers in 6.8 SPC because the only change beyond that needed is changing the follower in the magazines."
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NOW CUT THAT OUT! :a01: You must be reading over my shoulder...
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That would entirely depend on the round(s) selected for use, which is like step 55 at this point (and we're not even at step 1 yet, in all actuality)...
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I have been told by either an RRA factory rep or by the shop where I bought my RRA that changing the follower was essentially all that had to be done on the mag -- don't remember which it was. I didn't go beyond that as far as questioning the issue. I do know that I can stick a standard 5.56 mag in my RRA magazine well and it locks up nice and snug, so I've never really questioned just changing the follower. I note also that the RRA 458 Socom uses standard 5.56 mags with no changes at all, it just becomes single column feed with that big fat round.
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On a 5.56 PMAG, you can fit maybe 5-6 6.8 rounds in it before it starts to swell/bind up, and I imagine that you could fit a few more in a standard USGI mag (which I have never tried).
The dimensions and rib placement on the 6.8 mags are different, so there's no way just a follower change would work.
The .458 is true, however, as it uses standard mags (depending on the bullet used, completely unmodified). I have a .458 that I shoot with a good deal, and it's a damn fine rifle!
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I can put p_mags into my Stag marked 6.8 lower and they have no problems being snug. that said they do not work by just changing the follower or everyone here would have 6.8 p-mags like they want. Or a large supply of mags from all the 5.56 mags. There are no Colt mags with 6.8 followers that I know of.
That said this thread is about effective range of the 6.8 not mags lets keep it on topic.
LKirchoff was shooting his 18" SPC2 1:11 from Bison with factory and handloads in 115 smk's and was consistently ringing steel at 800. I pushed mine to 500 but ran out of ammo for it. I only brought 50 rounds for the SAM-R and used most of it on shooting the 300yd groups and plinking. So for steel and paper you can reach to 800. I bet you could get a little further as well.
That said this thread is about effective range of the 6.8 not mags lets keep it on topic.
LKirchoff was shooting his 18" SPC2 1:11 from Bison with factory and handloads in 115 smk's and was consistently ringing steel at 800. I pushed mine to 500 but ran out of ammo for it. I only brought 50 rounds for the SAM-R and used most of it on shooting the 300yd groups and plinking. So for steel and paper you can reach to 800. I bet you could get a little further as well.
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Sorry about the OT stuff...
I would be willing to say that the 6.8 is easily a 600 yard effective rifle against "zombies"...
There are plenty of hits at that range using 5.56 ammo and 77gr OTMs, and plenty of takedowns...and the 6.8 SPC has more "E" and mass at that range.
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Quicksilver, you asked what effective is. This is just my opinion, but if you are talking about hunting, then I would say out to the point where terminal energy is 800 ft. lbs. for deer sized game or smaller, including feral hogs. That's a pretty far piece with almost any rifle, so I would qualify that by saying that only to the extent of the ability of the shooter to hit consistently at that range.
Now, effective range on OTHER critters (two legged varmints) is entirely another thing. In that case, my criteria is about 500-600 yards for anything smaller than the 7.62 NATO round, but only about 200-250 yards for the 5.56. If I had to shoot beyond 600, then I would switch to my M1 with 168 grain HPBT at 2700 fps. That's good for 1000 yards if you can shoot that well.
An old Marine master gunny told me once that if he had a good M1 and an ammo can of M2 ball, and he could pick his terrain, he could hold up a division for three days minimum. This particular old MSgt saw the worst of the fighting in the Pacific island hopping campaigns and lived to tell about it, so I have no doubt he could do what he said.
Now, effective range on OTHER critters (two legged varmints) is entirely another thing. In that case, my criteria is about 500-600 yards for anything smaller than the 7.62 NATO round, but only about 200-250 yards for the 5.56. If I had to shoot beyond 600, then I would switch to my M1 with 168 grain HPBT at 2700 fps. That's good for 1000 yards if you can shoot that well.
An old Marine master gunny told me once that if he had a good M1 and an ammo can of M2 ball, and he could pick his terrain, he could hold up a division for three days minimum. This particular old MSgt saw the worst of the fighting in the Pacific island hopping campaigns and lived to tell about it, so I have no doubt he could do what he said.
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The ribs on the side of 6.8 mag are shallower than the 5.56 ribs, changing the follower in a 5.56 mag will not work no matter who said it. All AR15 mags have the same exterior dimensions as far as fitting in the mag well.
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Interestingly, while Ehrhart then seemed to advocate converting to 6.8 SPC, he now reportedly is proposing a 6mm round based on the 5.56 case:
http://castboolits.gunloads.com/showpost.php?p=905156&postcount=44
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My view is there are two effective ranges.
1) The maximum range that you can hit paper or steel at, limited by accuracy.
2) The maximum range that you have excellent terminal performance of the projectile and would hunt out to.
A fair upper limit for the maximum accuracy range is however far the round stays supersonic.
After it goes trans-sonic, anything might happen and all bets are off.
Maximum terminal performance range depends greatly on bullet construction and damage mechanism ( fragmentation, expansion, etc )
But it also depends on bullet velocity and energy.
May people quote ft-lbs of energy.
I like to use optimum game weight which is energy x momentum.
I think it is a more reliable indicator than just energy alone.
There are plenty of heavy slow bullets that to the job just as well as light, fast over energized bullets.
OGW is scaled to animal weight using a expanding type bullet.
I have arbitrarily picked 100 pound animal for the following list.
Here is a quick list of these ranges snagged out of another post.
SUPERSONIC RANGE
Maximum Range where velocity remains above 1075 fps
7.62x39 - 123 SP @ 2300 - 600 yards
6.8x43 - 115 SMK @ 2575 - 750 yards
5.56x45 - 62 gr M855 @ 3050 - 875 yards
6.8x43 - 110 AB @ 2630 - 900 yards
7x46 UIAC - 130 SMK @ 2650 - 975 yards
7.62x51 - 150 SMK @ 2750 - 1025 yards
6x42 - 90 FMJ @ 2900 - 1025 yards
7.62x63 - .30 M2 152 FMJ @ 2800 - 1075 yards
8x57 - 197 FMJ @ 2600 - 1175 yards
7.62x51 - M118LR 175 SMK @ 2600 - 1175 yards
6x42 - 95 SMK @ 2900 - 1225 yards
8.6x70 (338LM) - 250 HPBTM @ 2900 - 1850 yards
OPTIMAL GAME WEIGHT > 100 lbs RANGE
Maximum Range where OGW remains above 100 lbs
And with proper bullet selection can be expected to put down *game* up to 100 lbs
Actual value is related to momentum x energy, a very balanced indicator
5.56x45 - 62 gr M855 @ 3050 - 150 yards
7.62x39 - 123 SP @ 2300 - 250 yards
6.8x43 - 115 SMK @ 2575 - 350 yards
6x42 - 90 FMJ @ 2900 - 375 yards
6.8x43 - 110 AB @ 2630 - 400 yards
6x42 - 95 SMK @ 2900 - 500 yards
7x46 UIAC - 130 SMK @ 2650 - 550 yards
7.62x51 - 150 SMK @ 2750 - 700 yards
7.62x63 - .30 M2 152 FMJ @ 2800 - 725 yards
7.62x51 - M118LR 175 SMK @ 2600 - 900 yards
8x57 - 197 FMJ @ 2600 - 1150 yards
8.6x70 (338LM) - 250 HPBTM @ 2900 - 1900 yards
Interestingly, only the 8mm Mauser retains sufficient OGW and killing power out to its full supersonic range!
Also interesting is the 556 / 7.62x39 / 6.8 OGW match up.
The x39 has 100 yards on the 556, but the 68 has 100 yards on the x39!
Also that the hot rod universal intermediate rounds top out at about 500 yards with the best bullets,
but they fall short of the 308's 700/900 yard effective range.
1) The maximum range that you can hit paper or steel at, limited by accuracy.
2) The maximum range that you have excellent terminal performance of the projectile and would hunt out to.
A fair upper limit for the maximum accuracy range is however far the round stays supersonic.
After it goes trans-sonic, anything might happen and all bets are off.
Maximum terminal performance range depends greatly on bullet construction and damage mechanism ( fragmentation, expansion, etc )
But it also depends on bullet velocity and energy.
May people quote ft-lbs of energy.
I like to use optimum game weight which is energy x momentum.
I think it is a more reliable indicator than just energy alone.
There are plenty of heavy slow bullets that to the job just as well as light, fast over energized bullets.
OGW is scaled to animal weight using a expanding type bullet.
I have arbitrarily picked 100 pound animal for the following list.
Here is a quick list of these ranges snagged out of another post.
SUPERSONIC RANGE
Maximum Range where velocity remains above 1075 fps
7.62x39 - 123 SP @ 2300 - 600 yards
6.8x43 - 115 SMK @ 2575 - 750 yards
5.56x45 - 62 gr M855 @ 3050 - 875 yards
6.8x43 - 110 AB @ 2630 - 900 yards
7x46 UIAC - 130 SMK @ 2650 - 975 yards
7.62x51 - 150 SMK @ 2750 - 1025 yards
6x42 - 90 FMJ @ 2900 - 1025 yards
7.62x63 - .30 M2 152 FMJ @ 2800 - 1075 yards
8x57 - 197 FMJ @ 2600 - 1175 yards
7.62x51 - M118LR 175 SMK @ 2600 - 1175 yards
6x42 - 95 SMK @ 2900 - 1225 yards
8.6x70 (338LM) - 250 HPBTM @ 2900 - 1850 yards
OPTIMAL GAME WEIGHT > 100 lbs RANGE
Maximum Range where OGW remains above 100 lbs
And with proper bullet selection can be expected to put down *game* up to 100 lbs
Actual value is related to momentum x energy, a very balanced indicator
5.56x45 - 62 gr M855 @ 3050 - 150 yards
7.62x39 - 123 SP @ 2300 - 250 yards
6.8x43 - 115 SMK @ 2575 - 350 yards
6x42 - 90 FMJ @ 2900 - 375 yards
6.8x43 - 110 AB @ 2630 - 400 yards
6x42 - 95 SMK @ 2900 - 500 yards
7x46 UIAC - 130 SMK @ 2650 - 550 yards
7.62x51 - 150 SMK @ 2750 - 700 yards
7.62x63 - .30 M2 152 FMJ @ 2800 - 725 yards
7.62x51 - M118LR 175 SMK @ 2600 - 900 yards
8x57 - 197 FMJ @ 2600 - 1150 yards
8.6x70 (338LM) - 250 HPBTM @ 2900 - 1900 yards
Interestingly, only the 8mm Mauser retains sufficient OGW and killing power out to its full supersonic range!
Also interesting is the 556 / 7.62x39 / 6.8 OGW match up.
The x39 has 100 yards on the 556, but the 68 has 100 yards on the x39!
Also that the hot rod universal intermediate rounds top out at about 500 yards with the best bullets,
but they fall short of the 308's 700/900 yard effective range.
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Right now my effective range for hunting with my Robinson Arms XCR-L in 6.8 for smaller mule/white tail deer is 350 yards and by the end of the summer it will be 400 yards when I am shooting my 95gr TTSX/H322 loads.
I was up in the mountains near my home yesterday afternoon finishing the black bear hunting season off when I came to the end of a new cut/road I looked over to the old road and saw a perfect rock in the bank on the other side.
The rock is left of center and 20' left of the light coloured log that is laying straight up and down and is just above the trees that slid down the bank.
The first of 3 347 yard shots with my XCR-L in 6.8spc loaded with 95gr TTSX @ 2825fps just missed the rock low left and the next 2 shots hit appr 1 1/2" apart.
There was a 5 - 7 mph wind and I did not hold for windage wanted to see what kind of wind drift I would get with this load.
![Image]()
Here is the rock up close...
![Image]()
After I took the shots I had to drive my quad just over 1/2 mile back to the main road just before I got there a very nice chocolate brown black bear walked out in front of me but was gone into the thick bush before I could get the rifle loaded.
I was up in the mountains near my home yesterday afternoon finishing the black bear hunting season off when I came to the end of a new cut/road I looked over to the old road and saw a perfect rock in the bank on the other side.
The rock is left of center and 20' left of the light coloured log that is laying straight up and down and is just above the trees that slid down the bank.
The first of 3 347 yard shots with my XCR-L in 6.8spc loaded with 95gr TTSX @ 2825fps just missed the rock low left and the next 2 shots hit appr 1 1/2" apart.
There was a 5 - 7 mph wind and I did not hold for windage wanted to see what kind of wind drift I would get with this load.
Here is the rock up close...
After I took the shots I had to drive my quad just over 1/2 mile back to the main road just before I got there a very nice chocolate brown black bear walked out in front of me but was gone into the thick bush before I could get the rifle loaded.
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Interesting numbers, and valuable for relative comparison of calibers. You need to consider a couple of things, though. First, 150 lbs. is a more realistic weight for deer sized animals that are well fed. A mature, well fed Mulie buck can run 250 lbs. on the hoof, and I've seen plenty of whitetail bucks that tip 200 lbs. For does and yearlings, and smaller bucks, 150 is a good compromise.
Second, the average man is about the same weight range as a deer, but from what I've heard, a man is a lot easier to kill than a deer. The deer doesn't know he's supposed to lay down and die when he gets shot. If he's capable of running, he will try to get away. A man, on the other hand, is hampered by his reasoning. He knows he's been shot and likely dying, and tends to lay there calling for help. He pretty much throws in the towel.
I think the military probably has it as close to right as you get. There are many, many anecdotes of tangoes taking multiple hits from the 5.56 and continuing to fight even if the hits ultimately prove lethal. That's why 200 yards is often quoted as max effective range in that caliber. Since the majority of firefights in Afghanistan are in excess of 200 yards, that renders the 5.56 ineffective at best. The Army wouldn't be issuing M-14 rifles to many units as they are if the 5.56 was doing the job.
I'm curious, too, why the only full power rifle cartridge you included in your list was the 8mm Mauser? What happened to the 30-06? Most knowledgable people rate it a bit ahead of the 8mm, which at least in the U.S. tends to be underloaded. If the 7.62 NATO is good for 700 yards, the '06 is easily capable of 900-1000 yards. In fact, the old 03 Springfield was originally sighted out to 1200 yards if memory serves.
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