I am considering building a 6.8 SPC upper and my brain is about to hit overload status. After researching the caliber I have come across 6.8 SPC, 6.8 SPC II, and 6.8x43. Twist rates vary from 1/10 to 1/12 w/ most in the range of 1/11-1/12. Barel lengths vary from 16 in. to 20 in., w/ and w/o M4 feedramps. Barrels w/ a bolt, and barrels w/o a bolt. Noveske barrels are 6.8, as are DPMS. Wilson Combat barrels are chambered in 6.8 SPC II, as are the AR-Stoner barrels on Midway. The Midway barrels come w/ a 6.8 bolt already headspaced to the barrel. The 16 in. barrel comes w/ M4 feedramps, while the 20 in. barrel does not. I am looking to build the rifle to hunt with (deer & Varmint) and have basically decided on the AR-Stoner 20 in. barrel from Midway for the reason of a bit more velocity from the longer barrel over the 16 in barrel. What are your opinions on length and M4 ramped vs. Non-M4 ramped barrels? Also, for the purposes I am wanting the Noveske is a bit out of my price range.
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6.8 SPC is confusing
- Thread starter hilbillee
- Start date
Re: 6.8 SPC is confusing
It may be beneficial to visit the 68 forums, I personally would go with a 16-18" barrel in a spec II chamber. The M4 ramps depend on the upper you are using. If you have a stripped upper with ramps cut get one with M4 ramps to match. If your feeding it off the shelf ammo look at Silver State Ammo, they seem to be the leaders in this field. Also it might be worth your time to look here or call the dudes and pick their brains.
http://ar15performance.com/
It may be beneficial to visit the 68 forums, I personally would go with a 16-18" barrel in a spec II chamber. The M4 ramps depend on the upper you are using. If you have a stripped upper with ramps cut get one with M4 ramps to match. If your feeding it off the shelf ammo look at Silver State Ammo, they seem to be the leaders in this field. Also it might be worth your time to look here or call the dudes and pick their brains.
http://ar15performance.com/
Re: 6.8 SPC is confusing
The best place 6.8 info is the www.68forums.com if you have not been there yet. There are several manufactures on there that specialize in the 6.8 and there barrels are all the optimal specifications to shoot the hottest combat loads. You might also look at some of the ballistic testing over there and I think you will come the conclusion like I did that the a longer barrel does not get you that much more FPS to justify the weight.
M4 ramps are highly recommended for the 6.8. I agree about the information overload on the 6.8. Find a manufacture on 6.8 forums and order from there. Wilson Combat is on that site and uses all the updated specifications if your inclined to order from them.
The best place 6.8 info is the www.68forums.com if you have not been there yet. There are several manufactures on there that specialize in the 6.8 and there barrels are all the optimal specifications to shoot the hottest combat loads. You might also look at some of the ballistic testing over there and I think you will come the conclusion like I did that the a longer barrel does not get you that much more FPS to justify the weight.
M4 ramps are highly recommended for the 6.8. I agree about the information overload on the 6.8. Find a manufacture on 6.8 forums and order from there. Wilson Combat is on that site and uses all the updated specifications if your inclined to order from them.
Re: 6.8 SPC is confusing
What are you going to be doing with this rifle? if its strictly hunting than the 6.8 is a good choice, then of course all your options come into play.
I build quite a few of these and use the SPC II chamber.
good luck in your build and like the other guys said, 68forums is a great place to learn.
What are you going to be doing with this rifle? if its strictly hunting than the 6.8 is a good choice, then of course all your options come into play.
I build quite a few of these and use the SPC II chamber.
good luck in your build and like the other guys said, 68forums is a great place to learn.
Re: 6.8 SPC is confusing
Decide what do you want the upper to do, then decide the caliber. 6.8SPC is a great round to put down living things of a medium size within 300m. Its not the most accurate round, nor a good medium/long range round. Its made for terminal effects out of a AR15 platform.
America's 7.62X39, basically.
For the civilian hobbyist I think its a solution to a nonexistant problem. For deer and other medium game in cover it'd be great.
Decide what do you want the upper to do, then decide the caliber. 6.8SPC is a great round to put down living things of a medium size within 300m. Its not the most accurate round, nor a good medium/long range round. Its made for terminal effects out of a AR15 platform.
America's 7.62X39, basically.
For the civilian hobbyist I think its a solution to a nonexistant problem. For deer and other medium game in cover it'd be great.
Re: 6.8 SPC is confusing
It is going to be a strictly hunting rifle for up to 300 yds. For the longer ranges I have the 6.5 Grendel, and the 6.5 Creedmoor, along w/ the 223 Wylde chambered AR. Along w/ what Scottmilk9 & what sobrbiker said I have decided to go w/ the 6.8 SPC II. Plus I need another caliber to load for...lol. Thanks cg_wilson for the link to the 68 forums. One thing I forgot to ask though. The upper I have is a standard flat top upper w/ the m4 feed ramps. Will the ejection port be open enough for the 6.8 SPC round, or will I have to go for a different upper?
It is going to be a strictly hunting rifle for up to 300 yds. For the longer ranges I have the 6.5 Grendel, and the 6.5 Creedmoor, along w/ the 223 Wylde chambered AR. Along w/ what Scottmilk9 & what sobrbiker said I have decided to go w/ the 6.8 SPC II. Plus I need another caliber to load for...lol. Thanks cg_wilson for the link to the 68 forums. One thing I forgot to ask though. The upper I have is a standard flat top upper w/ the m4 feed ramps. Will the ejection port be open enough for the 6.8 SPC round, or will I have to go for a different upper?
Re: 6.8 SPC is confusing
If you want a hunting upper, Scott's your man.
Check his rep with predatormasters (in addition to his good standing here) then give him a call.
If you want a hunting upper, Scott's your man.
Check his rep with predatormasters (in addition to his good standing here) then give him a call.
Re: 6.8 SPC is confusing
Whether its a 16, 18 or 20" barrel do yourself a huge favor and get it with M4 ramps. As chambers go you should lean heavily towards the SPC-II or the 6.8x43 which both are literally the same. You would likely being doing yourself a favor by buying a barrel/bolt combination as they should be headspaced together. Now for twist rates most anything between 11 and 12 or better will handle all of the hottest loads.
Things to avoid, barrel/uppers lacking M4 ramps, the old SPC chambers and twist rates in the 9.5/10 range.
I've found my 6.8's to be exceedingly accurate, unless your shooting crappy Remington ammo and are a good bit hotter than 7.62x39 loadings.
The Noveske barrels are very nice and seem to run everything but they do come at a price.
Whether its a 16, 18 or 20" barrel do yourself a huge favor and get it with M4 ramps. As chambers go you should lean heavily towards the SPC-II or the 6.8x43 which both are literally the same. You would likely being doing yourself a favor by buying a barrel/bolt combination as they should be headspaced together. Now for twist rates most anything between 11 and 12 or better will handle all of the hottest loads.
Things to avoid, barrel/uppers lacking M4 ramps, the old SPC chambers and twist rates in the 9.5/10 range.
I've found my 6.8's to be exceedingly accurate, unless your shooting crappy Remington ammo and are a good bit hotter than 7.62x39 loadings.
The Noveske barrels are very nice and seem to run everything but they do come at a price.
Re: 6.8 SPC is confusing
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body">Decide what do you want the upper to do, then decide the caliber. 6.8SPC is a great round to put down living things of a medium size within 300m. Its not the most accurate round, nor a good medium/long range round. Its made for terminal effects out of a AR15 platform.
America's 7.62X39, basically.
For the civilian hobbyist I think its a solution to a nonexistant problem. For deer and other medium game in cover it'd be great. </div></div>
6.8 factory ammo is pushing 110gr bullets to 2600fps from a 16" barrel, handloaded 2750 is possible.
The little Barnes 85gr TSX has been driven to 3170 out of a 16" barrel and passes through hogs corner to corner. It is quite a bit more accurate than a 7.62x39 and some barrels shoot factory ammo less than 1 MOA which is plenty good enough for practical accuracy. Texas hog hunters are snatching these things up so fast it is unreal.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body">Decide what do you want the upper to do, then decide the caliber. 6.8SPC is a great round to put down living things of a medium size within 300m. Its not the most accurate round, nor a good medium/long range round. Its made for terminal effects out of a AR15 platform.
America's 7.62X39, basically.
For the civilian hobbyist I think its a solution to a nonexistant problem. For deer and other medium game in cover it'd be great. </div></div>
6.8 factory ammo is pushing 110gr bullets to 2600fps from a 16" barrel, handloaded 2750 is possible.
The little Barnes 85gr TSX has been driven to 3170 out of a 16" barrel and passes through hogs corner to corner. It is quite a bit more accurate than a 7.62x39 and some barrels shoot factory ammo less than 1 MOA which is plenty good enough for practical accuracy. Texas hog hunters are snatching these things up so fast it is unreal.
Re: 6.8 SPC is confusing
I'm not an expert, but I have looked into the 6.8. Here's how I've come to view it.It's not any harder than .223/5.56/Wylde, it's just less publicized. Here you go:
Chambers
6.8 SPC (the SAMMI spec) = .223 chamber (won't handle higher pressure loads)
6.8 SPC II = 5.56 (will handle higher pressure loads)
6.8x43 = Wylde (handles it all, gets a bit more velocity out of some loads)
Twist Rates
1 in 10 = 1 in 9 (works, not the best, watch your pressures)
1 in 11/1 in 12 = 1 in 8/1 in 7 (work better, depending on what you're shooting)
That may be oversimplified, but hope it helps.
I'm not an expert, but I have looked into the 6.8. Here's how I've come to view it.It's not any harder than .223/5.56/Wylde, it's just less publicized. Here you go:
Chambers
6.8 SPC (the SAMMI spec) = .223 chamber (won't handle higher pressure loads)
6.8 SPC II = 5.56 (will handle higher pressure loads)
6.8x43 = Wylde (handles it all, gets a bit more velocity out of some loads)
Twist Rates
1 in 10 = 1 in 9 (works, not the best, watch your pressures)
1 in 11/1 in 12 = 1 in 8/1 in 7 (work better, depending on what you're shooting)
That may be oversimplified, but hope it helps.
Re: 6.8 SPC is confusing
I ordered my 6.8 barrel from Wilson Combat. It's the 18" Recon in 6.8 SPC II and has the M4 feedramps. One step closer to finishing the build...lol.
I ordered my 6.8 barrel from Wilson Combat. It's the 18" Recon in 6.8 SPC II and has the M4 feedramps. One step closer to finishing the build...lol.
Re: 6.8 SPC is confusing
I have the LMT MRP in 6.8 w 18" barrel, and have no problem hitting 1' plates at 600 yards with it. I've used to mainly for hog hunting, and have had great success. Great round for hogs IMHO.
I have the LMT MRP in 6.8 w 18" barrel, and have no problem hitting 1' plates at 600 yards with it. I've used to mainly for hog hunting, and have had great success. Great round for hogs IMHO.
Re: 6.8 SPC is confusing
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hilbillee</div><div class="ubbcode-body">I ordered my 6.8 barrel from Wilson Combat. It's the 18" Recon in 6.8 SPC II and has the M4 feedramps. One step closer to finishing the build...lol.
</div></div>
This should work very well for you, time to find a few mags and some SSA ammo.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hilbillee</div><div class="ubbcode-body">I ordered my 6.8 barrel from Wilson Combat. It's the 18" Recon in 6.8 SPC II and has the M4 feedramps. One step closer to finishing the build...lol.
</div></div>
This should work very well for you, time to find a few mags and some SSA ammo.
Re: 6.8 SPC is confusing
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hilbillee</div><div class="ubbcode-body">I ordered my 6.8 barrel from Wilson Combat. It's the 18" Recon in 6.8 SPC II and has the M4 feedramps. One step closer to finishing the build...lol.
</div></div>
You could have saved $50 by getting a Bison, they are the exact same ss barrel made by Shaw,they shoot well though.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hilbillee</div><div class="ubbcode-body">I ordered my 6.8 barrel from Wilson Combat. It's the 18" Recon in 6.8 SPC II and has the M4 feedramps. One step closer to finishing the build...lol.
</div></div>
You could have saved $50 by getting a Bison, they are the exact same ss barrel made by Shaw,they shoot well though.
Re: 6.8 SPC is confusing
SAAMI SPC has a freebore of 0.050", SPC II has a longer freebore (.100). SAAMI SPC is more accurate so if you're not shoot SSA's "tactical" rounds, then you don't need SPC II.
The real story (not the marketing BS) behind why SPC II came about is interesting...
SAAMI SPC has a freebore of 0.050", SPC II has a longer freebore (.100). SAAMI SPC is more accurate so if you're not shoot SSA's "tactical" rounds, then you don't need SPC II.
The real story (not the marketing BS) behind why SPC II came about is interesting...
Re: 6.8 SPC is confusing
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: recce556</div><div class="ubbcode-body">SAAMI SPC has a freebore of 0.050", SPC II has a longer freebore (.100). SAAMI SPC is more accurate so if you're not shoot SSA's "tactical" rounds, then you don't need SPC II.
The real story (not the marketing BS) behind why SPC II came about is interesting... </div></div>
recce, as a 6.8 fan, could you elaborate?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: recce556</div><div class="ubbcode-body">SAAMI SPC has a freebore of 0.050", SPC II has a longer freebore (.100). SAAMI SPC is more accurate so if you're not shoot SSA's "tactical" rounds, then you don't need SPC II.
The real story (not the marketing BS) behind why SPC II came about is interesting... </div></div>
recce, as a 6.8 fan, could you elaborate?
Re: 6.8 SPC is confusing
I too am interested in hearing how freebore determines a barrel's inherent accuracy.
I too am interested in hearing how freebore determines a barrel's inherent accuracy.
Re: 6.8 SPC is confusing
Because most 6.8 SPC guns are magazine fed, you have limits on the bullet seating depth. With a 0.050" freebore, the bullet has a smaller "jump" to get to the lands. If it was a bolt gun, the 0.050" freebore difference between SAAMI and SPC II wouldn't matter because you can adjust your bullet seating depth since the magazine is not longer the restriction. People who reload match/benchrest/etc. generally prefer to set the bullet just slightly off the lands for improved accuracy. I don't know anyone that seats their bullets with excessive jump for accuracy, do you?
Rutgers, if you're referring to the story as to why SPC II came out, because I heard the info second hand (but through very reliable sources), I'll just say that it was developed to correct a ammo manufacturing problem.
Because most 6.8 SPC guns are magazine fed, you have limits on the bullet seating depth. With a 0.050" freebore, the bullet has a smaller "jump" to get to the lands. If it was a bolt gun, the 0.050" freebore difference between SAAMI and SPC II wouldn't matter because you can adjust your bullet seating depth since the magazine is not longer the restriction. People who reload match/benchrest/etc. generally prefer to set the bullet just slightly off the lands for improved accuracy. I don't know anyone that seats their bullets with excessive jump for accuracy, do you?
Rutgers, if you're referring to the story as to why SPC II came out, because I heard the info second hand (but through very reliable sources), I'll just say that it was developed to correct a ammo manufacturing problem.
Re: 6.8 SPC is confusing
Short freebore in gasguns can also be the culprit in many pressure problems found in the crazy directions we have taken Stoner's original design.
Short freebore in gasguns can also be the culprit in many pressure problems found in the crazy directions we have taken Stoner's original design.
Re: 6.8 SPC is confusing
Does this ammo manufacturing problem have anything to do with the throat shaving copper off a particular bullet?
If so, the story is worth looking into further. Throat angle was the issue with certain reamers, which were revised later on to address the problem. The newer reamers for 6.8x43 and SPCII corrected the issue. The additional leade allows for lower peak pressure, and as a benefit premits hotter loads.
Since the intented purpose of this cartridge from day one was for improved CQB ballistics, the comments regarding the effect on accuracy are a bit superfluous. Inside 300m, the accuracy discrepancy between a SAAMI spec chamber and SPCII are a non-issue. However I will admit a bias, since I do enjoy shooting 110gr TSX at 3000fps and 130gr SPBT's at 2550fps, which was impossible before with the SAAMI spec 1/10" twist bbl.
Does this ammo manufacturing problem have anything to do with the throat shaving copper off a particular bullet?
If so, the story is worth looking into further. Throat angle was the issue with certain reamers, which were revised later on to address the problem. The newer reamers for 6.8x43 and SPCII corrected the issue. The additional leade allows for lower peak pressure, and as a benefit premits hotter loads.
Since the intented purpose of this cartridge from day one was for improved CQB ballistics, the comments regarding the effect on accuracy are a bit superfluous. Inside 300m, the accuracy discrepancy between a SAAMI spec chamber and SPCII are a non-issue. However I will admit a bias, since I do enjoy shooting 110gr TSX at 3000fps and 130gr SPBT's at 2550fps, which was impossible before with the SAAMI spec 1/10" twist bbl.
Re: 6.8 SPC is confusing
The bullet was the major issue and it was the only bullet to exhibit this problem. And because a certain company invested heavily in the bullets, they decided to "update" the spec. Yes, added velocity was the benefit but at the cost of accuracy...that being said, you're right, if you plan on building a 6.8 SPC as a CQB weapon, then the accuracy issue is moot. I reload my own so I'm biased in that if I'm gonna spend the time to reload and develop a round for it, I want it as accurate as possible (which is why I don't reload AK rounds
). I also prefer not to burn out my barrels earlier than necessary (nor do I like overly punish my brass) so non "+P" velocities work better for me.
When I first got into the whole 6.8 SPC thing, I called Noveske (as one of 6.8's is a built around a Noveske barrel) and asked if they could update the chamber for SPC II, they offered to trade me my barrel for a new one with the SPC II chamber as they said they had customers that were specifically looking for SAAMI spec barrels. Go figure.
Now since the OP is looking for a hunting/varmint gun, I was thinking that accuracy was more important then velocity which is why I brought it up.
The bullet was the major issue and it was the only bullet to exhibit this problem. And because a certain company invested heavily in the bullets, they decided to "update" the spec. Yes, added velocity was the benefit but at the cost of accuracy...that being said, you're right, if you plan on building a 6.8 SPC as a CQB weapon, then the accuracy issue is moot. I reload my own so I'm biased in that if I'm gonna spend the time to reload and develop a round for it, I want it as accurate as possible (which is why I don't reload AK rounds
When I first got into the whole 6.8 SPC thing, I called Noveske (as one of 6.8's is a built around a Noveske barrel) and asked if they could update the chamber for SPC II, they offered to trade me my barrel for a new one with the SPC II chamber as they said they had customers that were specifically looking for SAAMI spec barrels. Go figure.
Now since the OP is looking for a hunting/varmint gun, I was thinking that accuracy was more important then velocity which is why I brought it up.
Re: 6.8 SPC is confusing
Your insight on bullet jump and rifle's intended use is valid and refreshing. I suspect the SAAMI spec barrel requests were done for peace of mind, as the majority if not all barrel makers for 6.8 have made the switch to SPCII. Interestingly enough, a few of them are still using 1/10" twist rifling. I don't think the slower 1/12" is ideal when considering the smaller bullets like the 85gr TSX, but more 'heavier' bullets are being introduced to the market for the 6.8 in the 120-130gr range and the 1/10" might re-emerge as the preferred configuration.
Your insight on bullet jump and rifle's intended use is valid and refreshing. I suspect the SAAMI spec barrel requests were done for peace of mind, as the majority if not all barrel makers for 6.8 have made the switch to SPCII. Interestingly enough, a few of them are still using 1/10" twist rifling. I don't think the slower 1/12" is ideal when considering the smaller bullets like the 85gr TSX, but more 'heavier' bullets are being introduced to the market for the 6.8 in the 120-130gr range and the 1/10" might re-emerge as the preferred configuration.
Re: 6.8 SPC is confusing
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: recce556</div><div class="ubbcode-body">
When I first got into the whole 6.8 SPC thing, I called Noveske (as one of 6.8's is a built around a Noveske barrel) and asked if they could update the chamber for SPC II, they offered to trade me my barrel for a new one with the SPC II chamber as they said they had customers that were specifically looking for SAAMI spec barrels. Go figure.
</div></div>
This is good to know as I was going to get a Noveske bbl for my RRA 6.8. I wonder if they still have this going on? The 6.8 is a hell of a round and as much as I love mine, I shoot my .223 more because it's cheaper. But a 12.5 with a switchblock and my sandstorm is where I'm headed as the 6.8 is a favorable round for an SBR. H335 is my powder of choice and I only use Large Rifle Primer brass from Rem or SSA.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: recce556</div><div class="ubbcode-body">
When I first got into the whole 6.8 SPC thing, I called Noveske (as one of 6.8's is a built around a Noveske barrel) and asked if they could update the chamber for SPC II, they offered to trade me my barrel for a new one with the SPC II chamber as they said they had customers that were specifically looking for SAAMI spec barrels. Go figure.
</div></div>
This is good to know as I was going to get a Noveske bbl for my RRA 6.8. I wonder if they still have this going on? The 6.8 is a hell of a round and as much as I love mine, I shoot my .223 more because it's cheaper. But a 12.5 with a switchblock and my sandstorm is where I'm headed as the 6.8 is a favorable round for an SBR. H335 is my powder of choice and I only use Large Rifle Primer brass from Rem or SSA.
Re: 6.8 SPC is confusing
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: recce556</div><div class="ubbcode-body">Because most 6.8 SPC guns are magazine fed, you have limits on the bullet seating depth. With a 0.050" freebore, the bullet has a smaller "jump" to get to the lands. If it was a bolt gun, the 0.050" freebore difference between SAAMI and SPC II wouldn't matter because you can adjust your bullet seating depth since the magazine is not longer the restriction. People who reload match/benchrest/etc. generally prefer to set the bullet just slightly off the lands for improved accuracy. I don't know anyone that seats their bullets with excessive jump for accuracy, do you?
Rutgers, if you're referring to the story as to why SPC II came out, because I heard the info second hand (but through very reliable sources), I'll just say that it was developed to correct a ammo manufacturing problem. </div></div>
LOL but, we can get more velocity out of the round as a result so it's all good.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: recce556</div><div class="ubbcode-body">Because most 6.8 SPC guns are magazine fed, you have limits on the bullet seating depth. With a 0.050" freebore, the bullet has a smaller "jump" to get to the lands. If it was a bolt gun, the 0.050" freebore difference between SAAMI and SPC II wouldn't matter because you can adjust your bullet seating depth since the magazine is not longer the restriction. People who reload match/benchrest/etc. generally prefer to set the bullet just slightly off the lands for improved accuracy. I don't know anyone that seats their bullets with excessive jump for accuracy, do you?
Rutgers, if you're referring to the story as to why SPC II came out, because I heard the info second hand (but through very reliable sources), I'll just say that it was developed to correct a ammo manufacturing problem. </div></div>
LOL but, we can get more velocity out of the round as a result so it's all good.
Re: 6.8 SPC is confusing
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Powder Burns</div><div class="ubbcode-body"> However I will admit a bias, since I do enjoy shooting 110gr TSX at 3000fps and 130gr SPBT's at 2550fps, which was impossible before with the SAAMI spec 1/10" twist bbl. </div></div>
how are you getting 3k out of a 110g?
I have been handloading and pushing the edge for several years on the 6.8
Most of us are getting around 2850 with the 95 TTSX and a max load of RL10x out of a 16-18" barrel
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Powder Burns</div><div class="ubbcode-body"> However I will admit a bias, since I do enjoy shooting 110gr TSX at 3000fps and 130gr SPBT's at 2550fps, which was impossible before with the SAAMI spec 1/10" twist bbl. </div></div>
how are you getting 3k out of a 110g?
I have been handloading and pushing the edge for several years on the 6.8
Most of us are getting around 2850 with the 95 TTSX and a max load of RL10x out of a 16-18" barrel
Re: 6.8 SPC is confusing
Everyone talks of the 6.8 as a 300 yard round.
If you are using a 20" barrel and using bullets of the same (or nearly so) B.C. as the 5.56, you get VERY similar velocities from a SPCII chamber and a slower twist barrel (1-11 or 1-12).
The Hornady VMax 110 grain bullet has, for all practical purposes, the same BC as the 77 grain SMK used in the 5.56 load
(as does the 110 grain accubond). Velocities are very similar with the "Combat" loads from SSA, over 2700 FPS from a 20" barrel with the 110 grain pill.
You can engage targets at 700 yards with either the 5.56 77 grain load or the 110 grain 6.8 combat loads and still be quite lethal.
No, it is not optimal, but it can be done.
Everyone talks of the 6.8 as a 300 yard round.
If you are using a 20" barrel and using bullets of the same (or nearly so) B.C. as the 5.56, you get VERY similar velocities from a SPCII chamber and a slower twist barrel (1-11 or 1-12).
The Hornady VMax 110 grain bullet has, for all practical purposes, the same BC as the 77 grain SMK used in the 5.56 load
(as does the 110 grain accubond). Velocities are very similar with the "Combat" loads from SSA, over 2700 FPS from a 20" barrel with the 110 grain pill.
You can engage targets at 700 yards with either the 5.56 77 grain load or the 110 grain 6.8 combat loads and still be quite lethal.
No, it is not optimal, but it can be done.
Re: 6.8 SPC is confusing
I don't know how deep your are into your build, but there is a nice noveske 6.8 upper for sale in the accessories thread.
I don't know how deep your are into your build, but there is a nice noveske 6.8 upper for sale in the accessories thread.
Re: 6.8 SPC is confusing
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kLewis</div><div class="ubbcode-body">I'm not an expert, but I have looked into the 6.8. Here's how I've come to view it.It's not any harder than .223/5.56/Wylde, it's just less publicized. Here you go:
Chambers
6.8 SPC (the SAMMI spec) = .223 chamber (won't handle higher pressure loads)
6.8 SPC II = 5.56 (will handle higher pressure loads)
6.8x43 = Wylde (handles it all, gets a bit more velocity out of some loads)
Twist Rates
1 in 10 = 1 in 9 (works, not the best, watch your pressures)
1 in 11/1 in 12 = 1 in 8/1 in 7 (work better, depending on what you're shooting)
That may be oversimplified, but hope it helps. </div></div>
This is a great post^^^^^
I would suggest reading a bit more on the 6.8 forums. I would also suggest that you go to AR15 performance for your upper. The chamber he uses, along with his nitrocarburized barrels, get higher velocities than others and can also handle hotter loads. Plus his Super Bolts are awesome. His guns are very accurate as well. They are priced quite nicely.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kLewis</div><div class="ubbcode-body">I'm not an expert, but I have looked into the 6.8. Here's how I've come to view it.It's not any harder than .223/5.56/Wylde, it's just less publicized. Here you go:
Chambers
6.8 SPC (the SAMMI spec) = .223 chamber (won't handle higher pressure loads)
6.8 SPC II = 5.56 (will handle higher pressure loads)
6.8x43 = Wylde (handles it all, gets a bit more velocity out of some loads)
Twist Rates
1 in 10 = 1 in 9 (works, not the best, watch your pressures)
1 in 11/1 in 12 = 1 in 8/1 in 7 (work better, depending on what you're shooting)
That may be oversimplified, but hope it helps. </div></div>
This is a great post^^^^^
I would suggest reading a bit more on the 6.8 forums. I would also suggest that you go to AR15 performance for your upper. The chamber he uses, along with his nitrocarburized barrels, get higher velocities than others and can also handle hotter loads. Plus his Super Bolts are awesome. His guns are very accurate as well. They are priced quite nicely.
Re: 6.8 SPC is confusing
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: fdkay</div><div class="ubbcode-body">Everyone talks of the 6.8 as a 300 yard round.
If you are using a 20" barrel and using bullets of the same (or nearly so) B.C. as the 5.56, you get VERY similar velocities from a SPCII chamber and a slower twist barrel (1-11 or 1-12).
The Hornady VMax 110 grain bullet has, for all practical purposes, the same BC as the 77 grain SMK used in the 5.56 load
(as does the 110 grain accubond). Velocities are very similar with the "Combat" loads from SSA, over 2700 FPS from a 20" barrel with the 110 grain pill.
You can engage targets at 700 yards with either the 5.56 77 grain load or the 110 grain 6.8 combat loads and still be quite lethal.
No, it is not optimal, but it can be done. </div></div>
I think most peoople are referring to 300 yards for ethical, clean kills for hunting.
400 yards is about the max to geta 95g TTSX to expand in soft tissue and still has the 1000 ft lbs of energy some people get hung up on (I don't)
I have banged steel at 750 yards with the 115 OTM and it moves the steel with authority and I sure as hell would not want to get hit with it... but 400 is really about the max for effective, clean 1 shot kills on game
now, hitting a guy COM and taking him out of the fight?
I am sure it's out past 500, but no one has reported any real world data to my knowledge
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: fdkay</div><div class="ubbcode-body">Everyone talks of the 6.8 as a 300 yard round.
If you are using a 20" barrel and using bullets of the same (or nearly so) B.C. as the 5.56, you get VERY similar velocities from a SPCII chamber and a slower twist barrel (1-11 or 1-12).
The Hornady VMax 110 grain bullet has, for all practical purposes, the same BC as the 77 grain SMK used in the 5.56 load
(as does the 110 grain accubond). Velocities are very similar with the "Combat" loads from SSA, over 2700 FPS from a 20" barrel with the 110 grain pill.
You can engage targets at 700 yards with either the 5.56 77 grain load or the 110 grain 6.8 combat loads and still be quite lethal.
No, it is not optimal, but it can be done. </div></div>
I think most peoople are referring to 300 yards for ethical, clean kills for hunting.
400 yards is about the max to geta 95g TTSX to expand in soft tissue and still has the 1000 ft lbs of energy some people get hung up on (I don't)
I have banged steel at 750 yards with the 115 OTM and it moves the steel with authority and I sure as hell would not want to get hit with it... but 400 is really about the max for effective, clean 1 shot kills on game
now, hitting a guy COM and taking him out of the fight?
I am sure it's out past 500, but no one has reported any real world data to my knowledge
Re: 6.8 SPC is confusing
Finally got everything to finish the build. Brass is on the way as are the mags. Now to get the time to assemble everything, load rounds, and test everything.
Finally got everything to finish the build. Brass is on the way as are the mags. Now to get the time to assemble everything, load rounds, and test everything.
