Today's State of the Art in 6.8 X 43 mm SPC

#51
Re: Today's State of the Art in 6.8 X 43 mm SPC

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: silver78</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HTR707</div><div class="ubbcode-body">

It is very important to note that even if you bought any of these barrels from any manufacturer, converting the SAAMI to SPC II chamber is ridiculously easy, by reaming out to the extra freebore, then equaling .100" which is .050" greater than the SAAMI.

</div></div>

So does this mean that any of the old barrels that are reamed as you describe will be safe to use with todays hot loads? If I recall correctly there was also a change in thinking on twist rates and I wonder if an older barrel with a fast twist rate will still exhibit problems even if reamed. Sorry - I'm no expert on this. I just want to make sure that everyone who wants to shoot the 6.8 is doing it in a safe manner. </div></div>

I have the LMT MRP Barrel that came with the 1:10"/6-Groove/SAAMI Chambered barrel and I reamed it out with the SPCII Reamer and it works much better now and it is very accurate for a chrome lined barrel (10 rounds at around 1.25 MOA).

Here is the break down:

Take a 1:10"/6-Groove/SAAMI Chambered barrel and convert it to the SPCII Chamber and you can go up 1 GR in powder, which equals approximately 100 FPS. Now the difference between a 1:10"/6-Groove/SPCII CHambered Barrel to a 1:11 or 1:12"/3, 4, or 5R Groove/SPCII Chambered barrel is you can go up another 1 GR so you get another 100 FPS.
<span style="font-weight: bold">So the difference from a 1:10"/6-Groove/SAAMI Chambered barrel to a 1:11 or 1:12"/3, 4, or 5R Groove/SPCII Chambered barrel is 2 GR of powder and approximately 200 FPS.</span>
 
#52
Re: Today's State of the Art in 6.8 X 43 mm SPC

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HTR707</div><div class="ubbcode-body">
You are the one that clearly seems biased against the 6.8. Why, I don't know. Have you ever fired one? Do you know what the recoil impulse feels like?
</div></div>

Yes.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HTR707</div><div class="ubbcode-body">
You seem to believe that the only viable purpose for it, is in the US military. If that were true, we could then argue its merits or disadvantages based solely upon military / tactical considerations.
</div></div>

I have only commented on considerations relating to practical use as a combat arm because I have a differing opinion on that topic and only that topic.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HTR707</div><div class="ubbcode-body">
But, since Paulosantos refuted every disadvantage you brought forth, and you still are telling us the round is not as good a 5.56, I find it completely worthless to argue with you.
</div></div>

You would make one hell of a terrible Judge. Your critieria for 'refuted' leave much to be desired.


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HTR707</div><div class="ubbcode-body">
I simply came here to post this for those that want to know more about the round. Many of these guys are hunters and LEO's. The will not care about magazine capacity or 1-2 ozs of weight in carrying ammo. If they did, they could simply buy Barrett mags and get 30 rounds. </div></div>

I understand your point and agree that mag capacity and weight may not be a worry for a hunter

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HTR707</div><div class="ubbcode-body">
In my opinion, a 6.8 rifle will outperform the 5.56 in any scenario you can imagine. That comes from 5 years of experience shooting and reloading for both, and hunting with both, killing hundreds of animals.</div></div>

My opinion differs from yours and I have 24 years in emergency services, treating humans. I have also killed deer with 5.56, 7.62 x 39 and 30-30. I feel this gives me some predictive ability in terms of wounding models for 6.8. I do not claim that the 5.56 is more lethel or even equal. I claim that both rounds are devastatingly lethal on the human model and that 'more kill' is not a terrible relevant advantage.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HTR707</div><div class="ubbcode-body">
There really is no comparison whatsoever, for me, anymore. the 6.8 SPC has made my 6 lb AR-15, with its 12 inch barrel, a completely viable hunting weapon, whereas before, it was a crippler. If you can bring that same level of experience to this forum (after doing the same ting with 6.8 SPC) and you have a different opinion, then I suspect members will want to hear it. If you have no experience with the 6.8, then I would suggest you try it....you might be surprised at how little you really know about it..</div></div>

I do not contest your stated opinion regarding your AR in 6.8 as a hunting tool. If you read this response from the top down, you already know my experience


 
#53
Re: Today's State of the Art in 6.8 X 43 mm SPC

To MedicJim and Ballistics: This thread was started by HTR to be an informational thread. It wasn't started to ask opinions on the 6.8 SPC. It is very clear to most of us from your previous replies in other 6.8 SPC threads that you guys don't like the 6.8 SPC and that is fine. But you guys have gone out of your way to turn this well intentioned thread into crap. That is rude and very unprofessional. If you guys want to bash the 6.8 SPC, why not start your own thread and bash it all you want?
 
#54
Re: Today's State of the Art in 6.8 X 43 mm SPC

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: medicjim</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HTR707</div><div class="ubbcode-body">
You are the one that clearly seems biased against the 6.8. Why, I don't know. Have you ever fired one? Do you know what the recoil impulse feels like?
</div></div>

Yes.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HTR707</div><div class="ubbcode-body">
You seem to believe that the only viable purpose for it, is in the US military. If that were true, we could then argue its merits or disadvantages based solely upon military / tactical considerations.
</div></div>

I have only commented on considerations relating to practical use as a combat arm because I have a differing opinion on that topic and only that topic.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HTR707</div><div class="ubbcode-body">
But, since Paulosantos refuted every disadvantage you brought forth, and you still are telling us the round is not as good a 5.56, I find it completely worthless to argue with you.
</div></div>

You would make one hell of a terrible Judge. Your critieria for 'refuted' leave much to be desired.


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HTR707</div><div class="ubbcode-body">
I simply came here to post this for those that want to know more about the round. Many of these guys are hunters and LEO's. The will not care about magazine capacity or 1-2 ozs of weight in carrying ammo. If they did, they could simply buy Barrett mags and get 30 rounds. </div></div>

I understand your point and agree that mag capacity and weight may not be a worry for a hunter

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HTR707</div><div class="ubbcode-body">
In my opinion, a 6.8 rifle will outperform the 5.56 in any scenario you can imagine. That comes from 5 years of experience shooting and reloading for both, and hunting with both, killing hundreds of animals.</div></div>

My opinion differs from yours and I have 24 years in emergency services, treating humans. I have also killed deer with 5.56, 7.62 x 39 and 30-30. I feel this gives me some predictive ability in terms of wounding models for 6.8. I do not claim that the 5.56 is more lethel or even equal. I claim that both rounds are devastatingly lethal on the human model and that 'more kill' is not a terrible relevant advantage.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HTR707</div><div class="ubbcode-body">
There really is no comparison whatsoever, for me, anymore. the 6.8 SPC has made my 6 lb AR-15, with its 12 inch barrel, a completely viable hunting weapon, whereas before, it was a crippler. If you can bring that same level of experience to this forum (after doing the same ting with 6.8 SPC) and you have a different opinion, then I suspect members will want to hear it. If you have no experience with the 6.8, then I would suggest you try it....you might be surprised at how little you really know about it..</div></div>

I do not contest your stated opinion regarding your AR in 6.8 as a hunting tool. If you read this response from the top down, you already know my experience


</div></div>


Jim,

Thanks for your input. This may surprise you, but I, too have over 20 years experience as a physician. I no longer work in a trauma center (thank God) but my training there was enough to provide me with plenty of predictive and foundational tools for assessing the lethality of wounds on animals / tissue.

When I pair that with over 35 years of hunting experience, I have come to the conclusion that for certain double-tough animals, .223 / 5.56 caliber is NOT enough.

These beasts can take a beating and keep going. I was skeptical of the 6.8 and its ability at first, but after seeing the advancement of the cartridge to what it is today, I just thought I'd like to share that with some of you.

Billyspig.jpg
 
#55
Re: Today's State of the Art in 6.8 X 43 mm SPC

For over a year, I have had the yen to buy a 6.5 Grendel upper. Have also thought much about the 6mmAR Turbo.

The problem with the AR-15 platform is magazine length. The problem with the AR-10 is weight. Barrel extension, bolt carrier group and barrel diameter all contribute that extra couple pounds. You lose any advantage the lighter weight munition might've had. So...


Haven't bought another upper for the 15. I like 75/77gr match bullets for toughness, and bet they would match the hog killers HTR cites. There's always 90gr SMK & JLK. A guy in Canada shooting a bolt .223rem at 1000yds got 2.5" vertical dispersion in 15-20 rd groups shooting over a thousand rounds of ammo...

I cut my longrange teeth on a .270; but where are the 130/140 gr bullets that can be used in the SPC?

I do have a 6mm/.22-250AI AR-10 upper. 107gr matchkings might work in the SPC case.

Who needs the 6.8 SPC? Mil-Surp brass would seem to be the real advantage, but then you could do a 6x45?

I think the 6mmAR Turbo AI is the ultimate round for the AR-15 lower. 107gr and 1000yd accuracy is all you could fancy, but when a Texan fancies he'll take his chances; chances will be taken...

Maybe a .30/6mmAR Turbo AI is really the way to go?
Load that baby with 155gr Scenars or SMK and see whatcha get?
Be kinda like a .300 Savage with AI and rebated rim.
 
#56
Re: Today's State of the Art in 6.8 X 43 mm SPC

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Swamper</div><div class="ubbcode-body">For over a year, I have had the yen to buy a 6.5 Grendel upper. Have also thought much about the 6mmAR Turbo.

The problem with the AR-15 platform is magazine length. The problem with the AR-10 is weight. Barrel extension, bolt carrier group and barrel diameter all contribute that extra couple pounds. You lose any advantage the lighter weight munition might've had. So...


Haven't bought another upper for the 15. I like 75/77gr match bullets for toughness, and bet they would match the hog killers HTR cites. There's always 90gr SMK & JLK. A guy in Canada shooting a bolt .223rem at 1000yds got 2.5" vertical dispersion in 15-20 rd groups shooting over a thousand rounds of ammo...

I cut my longrange teeth on a .270; but where are the 130/140 gr bullets that can be used in the SPC?

I do have a 6mm/.22-250AI AR-10 upper. 107gr matchkings might work in the SPC case.<span style="color: #FF0000">you will lose velocity due to effeciency and the 107 is a little long, the 95SMK works if the case is shortened to 41mm</span>

Who needs the 6.8 SPC? Mil-Surp brass would seem to be the real advantage, but then you could do a 6x45?

I think the 6mmAR Turbo AI is the ultimate round for the AR-15 lower. 107gr and 1000yd accuracy is all you could fancy, but when a Texan fancies he'll take his chances; chances will be taken... <span style="color: #FF0000">107=2700fps max from a 22" barrel 2600fps from a 18" </span>

Maybe a .30/6mmAR Turbo AI is really the way to go?- <span style="color: #FF0000">7.62x39 +100fps maybe</span>
Load that baby with 155gr Scenars or SMK and see whatcha get?
Be kinda like a .300 Savage with AI and rebated rim. </div></div>

I would just say compare and double compare actual performance so you aren't dissapointed with the velocities.
I have had many people call about a custom barrel but then when I tell them the velocities that are really possible they compare them to the 260 and rethink their choice. Since this is an AR I use 20" barrels to compare. A 107 from a 6mmAR turbo will hit 2650-2700, a 107 from a 260 will hit about 3000-3050. A 110gr from a 20" 6.8 will hit 2850-2900.
 
#57
Re: Today's State of the Art in 6.8 X 43 mm SPC

Just my $.02,

If I were trying to kill anything larger than a coyote,man or beast, between these two debated cartridges,I'd rather have a 6.8 SPC over 5.56 for sure.More wallop!

If I were to have a AR-15 carbine with 16" barrel or less for self defense,I'd just get a 6.8SPC and be happy.

I happen to own a 6mmAR turbo 40 and can't comment on what velocities could be achieved with 105gr bullets in carbine length barrels but I do know that with 105's 2925 fps is achievable and with 95's 3050 fps is achievable out of a 26 inch barrel.I wouldn't be surprised if I got 3150 fps out of the 26 inch barrel with the 85gr TSX.For additional info,Just the other day I was shooting 115 DATCS at 2675 fps.

The nice thing about the 6mmART's is that they make a very good long range cartridge as well.I shoot at 1000Y with it quite often and it does a fantastic job.

Steve

 
#58
Re: Today's State of the Art in 6.8 X 43 mm SPC

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Swamper</div><div class="ubbcode-body">For over a year, I have had the yen to buy a 6.5 Grendel upper. Have also thought much about the 6mmAR Turbo.

The problem with the AR-15 platform is magazine length. The problem with the AR-10 is weight. Barrel extension, bolt carrier group and barrel diameter all contribute that extra couple pounds. You lose any advantage the lighter weight munition might've had. So...


Haven't bought another upper for the 15. I like 75/77gr match bullets for toughness, and bet they would match the hog killers HTR cites. There's always 90gr SMK & JLK. A guy in Canada shooting a bolt .223rem at 1000yds got 2.5" vertical dispersion in 15-20 rd groups shooting over a thousand rounds of ammo...

<span style="color: #CC0000">I cut my longrange teeth on a .270; but where are the 130/140 gr bullets that can be used in the SPC?</span>

I do have a 6mm/.22-250AI AR-10 upper. 107gr matchkings might work in the SPC case.

Who needs the 6.8 SPC? Mil-Surp brass would seem to be the real advantage, but then you could do a 6x45?

I think the 6mmAR Turbo AI is the ultimate round for the AR-15 lower. 107gr and 1000yd accuracy is all you could fancy, but when a Texan fancies he'll take his chances; chances will be taken...

Maybe a .30/6mmAR Turbo AI is really the way to go?
Load that baby with 155gr Scenars or SMK and see whatcha get?
Be kinda like a .300 Savage with AI and rebated rim. </div></div>


Here are two of them:

The 130 grain Sierra Game King and the 130 grain Combined Technology Ballistic Silvertip may be loaded, as you can see, but the BST is s little too long for <span style="font-style: italic">super</span>sonic loads. It makes one HELL of a <span style="font-style: italic">sub</span>sonic round, though. The one you see pictured here, is the 130 grain BST over 7.2 grains of Trail Boss, in SSA Brass, with Wolf Primer, and loaded to 2.29" COAL.

It produces 1040 FPS in my 12 inch WOA stainless barrel, and is unbelievably quiet. I have already killed 2 hogs with neck shots, using the 130 BST subsonic. One went down on the spot, and the other ran about 40 yards where we heard it thrash around in the bushes, and we presume it died there.

(this is another nice attribute of the 6.8. Subs can be loaded from 90 to 150 grains, and no filler is required. They are as quiet as the .300 whisper.)

DSCF8004.jpg
 
#59
Re: Today's State of the Art in 6.8 X 43 mm SPC

I may not be an expert in this discussion but the reason I love the 6.8mm is I can hunt with it. I can't hunt with a 22 cal bullet in Virginia. I can hunt with the 6.8mm and carry a light AR body - win-win for me. I have two 6.8mm's - An AR Performance Upper built by Harrison B. and a LWRC M6A2. Both of the rifles are top notch. All I can say is that they kill what I point at - White Tail normally.

HTR and Paul - outstanding review. I have learned a lot by reading this thread. Thanks for taking the time to discuss the 6.8mm. Sometimes it is a hard sell to 5.56mm lovers. I have no problem using them both.
 
#60
Re: Today's State of the Art in 6.8 X 43 mm SPC

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HTR707</div><div class="ubbcode-body">
When I pair that with over 35 years of hunting experience, I have come to the conclusion that for certain double-tough animals, .223 / 5.56 caliber is NOT enough.
</div></div>

No contest, my position has always been focused on the human animal, which definitely does not qualify as 'double tough'.


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: paulosantos</div><div class="ubbcode-body"> But you guys have gone out of your way to turn this well intentioned thread into crap. That is rude and very unprofessional. </div></div>

Paul,

I think you are off base with your accusations directed at me, however, I will respect your request and cease posting on this thread.
 
#61
Re: Today's State of the Art in 6.8 X 43 mm SPC

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: medicjim</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: paulosantos</div><div class="ubbcode-body"> But you guys have gone out of your way to turn this well intentioned thread into crap. That is rude and very unprofessional. </div></div>

Paul,

I think you are off base with your accusations directed at me, however, I will respect your request and cease posting on this thread. </div></div>

Thank you Jim. Although we may not agree on the 6.8SPC, I respect your opinion and thank you for being understanding.
 
#63
Re: Today's State of the Art in 6.8 X 43 mm SPC

I'm not a huge fan of the 6.8 SPC cartridge. I'm an LEO and for my purposes, the .223 is sufficient. But only because I'm able to use the best ammo. Military users are limited in the types or rounds they can use.

As far as lethality, I don't give a shit whether the guy I shoot dies or not. I care that he stops doing what he's doing ASAP. A .22 caliber drilled clean through someone will not cause them to stop their actions unless the shot is very lucky. A cartridge that has the same velocity and twice the bullet weight has got to be more efficient at actually putting someone down. If I shoot someone and they can continue to fight for 5 or 10 minutes, like what was seen in Somalia, that is not a success for the round.

As far as Ballistic's argument, who really cares if the round has a high BC for MOUT operations. That would be more of concern in the mountains of A-stan, but not so much for LE or Military operators in urban terrain. The argument that a smaller, lighter, slower bullet is just as effective because it has a high BC is a little hard to follow. I'm guessing his argument is that because of the high BC the bullet retains more energy past 500 yds (or whatever yardage it takes the lead). I'd much rather have a 200 yards stopper, than a round that I can shoot 1000 yards with.
 
#66
Re: Today's State of the Art in 6.8 X 43 mm SPC

Here's what LWRC has to say about the 6.8. I don't even know why there is an argument here.

http://www.lwrci.com/Technology/Why68mmSPC/tabid/91/Default.aspx

I have a 6.8 and I love it. If I get a deer tag this year, that's probably what I'll take my deer with(can't use the .223 here). I have ARs in 4 different calibers and shoot the .223 the most(cheapest). My 6.8 is a DI RRA and I've put more than 250rds through it suppressed(.30 cal can) w/o a malfunction, although it's very dirty afterwards. All of the mags I've used are C-prducts 25rd stainless steel w/ MagPul followers. If you can have more punch from the same platform; why not?

If I shoot a deer I plan on using a 110 grain Accubond, probably backed by H335. .223 is great for coyotes and such, but for long pig I'd rather have a little more knock down power.
 
#67
Re: Today's State of the Art in 6.8 X 43 mm SPC

Thanks for your replies, guys.

We have tried to simply state some facts about the 6.8 X 43mm SPC here. It is evolving into something other than that which was released to the market 4-5 years ago. I just want all of you to know that, so you can make an informed decision as to whether to buy one now or not.

I find it somewhat amusing that LWRC talks about "being ahead of the curve..." To this day, they still make their rifles with 1:10 twist, though we have shown that 1:11 or 1:12 is optimal for this platform, especially when you start to consider the bullet weight trends......which is toward the lighter ones.

You do not need 1:10 twist for 85, 90 or 100 grain bullets. NO ONE loads the 6.8 SPC with 130- 150 grain bullets. They make great rifles, but ARPerformance was 3 years ahead of them when all the newer, upgraded rounds started to be loaded, and the cartridge really pushed ahead in performance.
 
#68
Re: Today's State of the Art in 6.8 X 43 mm SPC

I'm planning on purchasing a 6.8 upper for hunting hogs and deer. This post has been very informative. Thanks for all the info especially HTR707. I'm probably going to get an AR Performance 6.8 XT, my budget is about $700, and as I'm going to be beating bush I don't want it any heavier or bulkier than required. Any suggestions? Thanks!

BTW This is my first post and this seems to be a great forum!
 
#69
Re: Today's State of the Art in 6.8 X 43 mm SPC

Over stabilisation is the ruin of many a good bullet - and many people and manufacturers seem unable to differentiate the needs of the military -who want penetration with FMJ bullets through armour and cover, vs the needs of the hunter or Law enforcement officer who needs good bullet expansion and quick 'put down' times.

In general, enough stabilisation to produce good accuracy is all a hunter wants. Any more detracts from the bullets killing power (unless you are hunting elephant and using FMJ's- then you really need over stabilised bullets!).

A good example of this is the 5,56 Nato.

We had a few old AR15's with 1:14 twist. They shot patterns at 100m, but when the bodies of those shot with them arrived in my lab, the results were impressive. The FMJ bullets really tore people up. It was an effective stopping round.

We then recieved newer M16's with 1:12 twist. Chest shots in particular were not impressive with FMJ's and the lads switched to 55grn Samson OTM bullets. Still not as effective as FMJ's out of the old barrels but nice tight groups on the targets improved confidence (even though most fire fights were at 20m or less)

We then recived a batch of FNC's 1:9 twist. Terminal performance on people even with the OTM bullets dropped even more - and the lovely FNC's and the new SIG 551's were given to 'support' folk like me and the kill teams went back to their M16's.

Looking at the 6.8 SPC, those who use the 1:12 twist are going to see better terminal results and be happie (on Average) than those who use a twist that is designed for 150grn bullets at a much higher velocity.
 
#70
Re: Today's State of the Art in 6.8 X 43 mm SPC

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I don't even know why there is an argument here. </div></div>

I've got to agree with this.

Thanks for the information gentlemen and especially the tip about the simple reaming operation. I have one of the original SPC barrels and had thought changing the chamber was an expensive proposition.

Paul...I sent you an e-mail before I realized you probably don't send your reamer out anymore. You might let me know of anyone else who offers this service.
Thanks....Pete
 
#71
Re: Today's State of the Art in 6.8 X 43 mm SPC

From a hunting stand point, there are limitations as to bullet diameter that one can use on deer. In Nebraska, the criteria was ft/lb of energy at 100 yards. .223 was allowe, while .222 Remington was not. Some states care only about bullet diameter and most won't allow a 5.56 dia bullet to be used on deer.

I've shot deer from everything from .223 Remington all the way up to .338 Winchester Mag. I would prefer to shoot a deer with a little bit bigger bullet than the .224 dia bullet. The degree of shock and knock down would be better with the 6.8 x 43 or the 6.5 Grendel, or .260 Remington. If I was heading into a war and got to pick a rifle, the last rifle I'd grab would be the 5.56 NATO,ESPECIALLY the DI gas op type, and would probably take the 6.8 SPC II. I want to be able to make cover dissappear and want the bullet to penetrate, irregardless of what the enemy is hiding behind (car) or is wearing or happen to have been carrying. I would even prefer the 7.62 x 39 Soviet to the 5.56 NATO for CQB.

My decisions and opinion come from shooting since I was 8 (1961) and hunting deer, elk and other animals with all sorts of weapons, and shooting all sorts of odd stuff when I was younger and shot at our local junk yards (very rural), and the info I learned at the Law Enforcement Training Center in Grand Island, NE for my certification.

I came here for info, and found it. I like the idea of the 6.8 SPC II and for what it is. Longest deer kill was many years ago with a 7mm Remington Magnum at 700 yards. But, for average deer hunting I would imagine the actual average to be between 50 and 150 yards tops. In this range the 6.8 X 43 should do very well.
 
#73
Re: Today's State of the Art in 6.8 X 43 mm SPC

No one I know of, I have some 12x3 and Pac Nor will make you a 13x3 blank but no one has a 11x3 button as far as I know.
There are plenty of 11x4. It is the land to groove ratio that that is important unless like some you believe a 3 groove will foul less and clean easier.
 
#74
Re: Today's State of the Art in 6.8 X 43 mm SPC

you guys that are knocking the 6.8 are not the brightest or just very bias.

I would of loved to have the 6.8 over the 5.56 in combat. It can do everything the 5.56 can but better. ( only difference maybe long range shooting for punching paper not holes in people)
 
#75
Re: Today's State of the Art in 6.8 X 43 mm SPC

the 5.56 is a very un predictable round. I will give it that. I have not treated any victims of shootings but have been the giver of some wounds.
 
#76
Re: Today's State of the Art in 6.8 X 43 mm SPC

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: paulosantos</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: medicjim</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: paulosantos</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: medicjim</div><div class="ubbcode-body">

<span style="text-decoration: underline">Downsides</span>


-Greater recoil impulse means longer recovery time for a second aimed shot
<span style="color: #FF0000">A properly set-up 6.8SPC is very similar to the 5.56. There was an independent test conducted that proved it. DocGKR actually posted the times and the 6.8SPC was actually a fraction of a second faster in CQB drills. I know you are going to say I'm full of shit, but facts are facts.</span>

</div></div> </div></div>

I'm not going to say you are full of shit, but I am going to suggest that perhaps the reason you believe this has more to do with Bias than Fact. The 6.8 ejects greater mass in both bullet and gasses, which means it will have a greater gross recoil, if the weapon systems are the same, it should have greater NET recoil. That's basic science. If you make claims contrary to established science, you need to come up with some compelling reason why we should believe the world is flat.

</div></div>

The test was conducted and the guys testing didn't know what they were shooting. If you think the test was biased, then we are just going to go back and forth all day long. The test was not biased.

The reason that the SPC has similar recoil to the 5.56 is that the SPC uses faster powders. The 5.56 uses powders such as TAC, H4895, Varget, BLC-2, while the SPC uses powders such as H4198, H322, RE7, RE10X, X-Terminator.

Anytime you want to go to the range, I'll prove it to you, even with my over-gassed LMT barrel. </div></div>

I recently built a 6.8 and it definitely has more felt recoil than the .223. My 6.8 weights a little more than my .223 and the recoil diff is quite noticeable. I was shooting them side by side just to test that exact thing. But with an AR it is more of a straight back recoil so it still is pretty dang fast.


I will say the 6.8 is one sweet round. I would much much rather have it on a hunting trip than the .223 if I had the choice. I love the fact that they keep offering all the new options for the ARs.
 
#77
Re: Today's State of the Art in 6.8 X 43 mm SPC

I now have a Rock River Arms 16" barrel in 6.8 SPC II chamber, and an Adams Arms piston system. Recently with a hand load of Benchmark at 31.3 grain I pushed a 110 grain Sierra Spitzer to around 2760 average fps, and a nice group of around 3/8" MOA at 100 yards.

One other I am thinking of getting soon is a DEZ Arms, Inc., 6.8 SPC II in a 10.5 twist barrel. They have Chrome Moly Vanadium steel with a non chrome lined barrel. My current RRA is a 1 in 10 twist SPC II, and I think it's (6.8 SPC) great!
 
#78
Re: Today's State of the Art in 6.8 X 43 mm SPC

What exactly is the argument that the 6.8 is not superior to the 5.56?
Let's see, the 110 grain match .277 bullet has nearly the same ballistic coefficient as the 75 grain match .224 bullet. So, if velocity is equal, drop will be pretty much the same.
So, what! You say.
Well, how about this, the 6.8 is using a bullet 35 grains heavier. Duh. It hits with more energy, it penetrates better. It does EVERYTHING better than the 5.56.
They are now driving the barnes TSX 85 grain to similar velocities as the 55 grain M193 load. Again, 30 grains heavier, guess what, IT HITS HARDER!
I carry a 5.56 in the performance of my duties. I am COMPLETELY confident that in the event that I must use it against a perp that is not behind cover, or in an automobile, it will work.
HOWEVER, if I must shoot through the windshield, i am better off using my duty sidearm because barrier penetration SUCKS with the 5.56.
For the jackass that was implying Dr. Roberts is full of shit, Dr. Roberts happens to be one of the militaries foremost experts on wound ballistics.
The reason for the 6.8 chambering is simple, they found that it was an excellent compromise between the high bc's of the 6 mm and the incredible terminal performance of the 7mm 130 grain bullet. With the limited overall length, they could not get the velocities needed for the 7mm bullet, and the 6mm did not have the same CQB terminal effectiveness.

The 5.56 is a very good round, but in every test conducted, the 6.8 was VASTLY superior in terminal performance. I believe that it is ALMOST the ideal police marksman round. It has NONE of the drawbacks of the 5.56/223 platform(better intermediate barrier penetration, better terminal performance) and none of the drawbacks of the .308 (over penetration, slow follow ups).
It is not perfect, but it is an improvement that fits in an already existing envelope.
 
#79
Re: Today's State of the Art in 6.8 X 43 mm SPC

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AKsarben</div><div class="ubbcode-body">Who puts out a 3 grove 1:11 twist barrel? </div></div>
There is that barrel maker in Washington state, the name escapes me, they do not have a website, but specialize in 3 groove barrels.
 
#80
Re: Today's State of the Art in 6.8 X 43 mm SPC

I have both .223 bushmaster and lwrc m6a2 6.8. I actually got my muzzle break from paulosantos (thanks again) and the recoil difference is not that great. I think it's similar to the 9mm vs the .40, one is just a tad more snappy.

To the OP, thanks for posting and I'll be sure to look out for more of your posts. Wish I had a range that was my backyard like you..lol

I'm not really sure what the arguing is for here. The OP posted to be informative and all of the sudden you get some people trying to knock his analysis. Analysis I might add that can be backed up on 68forums.com. In every possible manner, the 6.8 is a superior round to the 5.56 and neither are sniper rounds. I wonder how many here knocking the 6.8 even realize that at 200yds, the 6.8 still retains more energy than the 5.56 at muzzle? If your looking for a killer out to 400yds for prey up to 400lbs in a package that is lightweight, shorter barrel, more functional, an in versatile platform...6.8 is your round....
 
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