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> 6.8 SPC
6.8 SPC
@ 08:33 pm (GMT) |
Nathan FosterI had an email from a reader today, remarking on the merits of the 6.8. Below is my reply. To my readers who do not have first hand experience with military ball ammo, please trust me in this, there is so much rubbish pushed on to people now..................... Hi ..., I must be up around 11,000 to 12,000 head of game now. But then I am told that I tend to understate these figures. I have taken atleast 1000 head of game with military rifles and FMJ ammo. There are so many combos and varieties of ammo I have used now that I have lost count but I can mention some basic cartridge designs here including the 5.56, 6.5, 7x57, 7.62x39, .30 Carbine, 7.62 Nato, .303 Brit and the 7.62x54, plus hand gun calibers. From these experiences, I can tell you that designing a low velocity .270 cal assault cartridge is bollocks. If you have ever shot an animal in close with the 7.6x39 cartridge and FMJ ammo where energy is high yet performance is still relatively useless, you will know just what I mean. Projectile design is always the key factor, not paper figures. This really comes down to money and marketing. It's always the way these days- follow the money. I do not want to see any of my readers caught out thinking that the 6.8 is the answer to their ills because with FMJ ammo, no matter how slick the BC and energy, it all means nothing if it just pin holes through. Actually, the higher the more inherently stable the bullet is in flight, the worse it is on target with regards to wounding, lacking the ability to initiate nervous trauma. There is so much to this, more than I can cover in one email sorry. I get tired of these so called military experts trotting out the same old rubbish without really having a deep understanding of terminal ballistics, contrary to what the general public might think. As for our own military, we are steadily going back to 7.62 / .308 using a decent projectile design that will blow the heads clean off these f-wits that are now causing trouble in the middle east. 6.8- follow the money. .300 Blackout- follow the money. Cheers, Nathan. |
Replies
@ 10:03 pm (GMT) |
Martin TaylorRe: 6.8 SPCYes, follow the money indeed!This “latest and greatest thing” where the newest thing on the market must be the best is absurd. The Industry is in a strange place at the moment so it is no wonder that you are so busy answering these emails Nathan. If the 223 was not adopted as a NATO calibre it would not even rate a mention in any hunting camp. I commented to my son only last night whilst loading our first ladder test "Imagine going into a conflict armed only with this bloody thing"………. If you get a chance to read Blackhawk Down one of the soldiers states how ineffective the 5.56 is and how much he respected the sniper who carried and preferred the 308w-M14 for its stopping power. I cannot legally shoot deer with this round here but we give it to our soldiers as their primary calibre?? |
@ 01:41 am (GMT) |
Mike NeesonRe: 6.8 SPCI am an avid reader of Col Jeff Cooper and this reminds of a phrase he would often use for new beut cartridges - "What is it for"? |
@ 01:48 pm (GMT) |
Joshua MayfieldRe: 6.8 SPCWhile I feel safe saying that any pilot will tell you there is plenty out of kilter in the aviation industry, I do wish companies in the arms and ammunition business would be as thorough and as transparent in their R&D as we ask civil aviation manufacturers to be. Maybe I'm being naive, but it seems that a culture of that sort would allow the average consumer to build up better immunities to slick advertising and overzealous magazine articles.Honest question... do you think that in extended times of peace militaries adopt cartridges (primary consideration is $$$, I think we all agree there) in part because the thought creeps into meeting rooms that we don't want bullets to be too lethal and destructive? I believe the man/woman in uniform who will be pulling the trigger and facing fire would want the most lethal and destructive armament possible. But do the people who make decisions without setting foot on a battlefield mandate FMJ in part because a non-lethal wound from that sort of bullet may be thought to be less mutilating than a non-lethal wound from an expanding bullet? Or do you think it is purely and solely about the money? |
@ 03:00 pm (GMT) |
Peter BjerregaardRe: 6.8 SPCJoshua,The Hague Convention of 1899 (yes, 1899) states, that bullets in international warfare must not be designed to expand. Still ratified today.. So it's not a cost issue. //Peter |
@ 03:33 pm (GMT) |
Warwick MarflittRe: 6.8 SPCWhat bullets do the police use to shoot people.? FMJ or expanding hunting projectiles? What would you like to be shot with? A-Max, Partition, Berger or Hornaday GMX? Have a read of this for a views about War and the true costs of it?content://com.sec.android.app.sbrowser/savepage/0808133909.mhtml |
@ 08:53 pm (GMT) |
Thomas KitchenRe: 6.8 SPCyou got to laugh most countries in the world has spent millions of dollars trying to get there fmj to perform more like expanding/fragmenting projectiles within the Hague convention rules then hunters come along and try to use fmj for hunting?? if you can use the better projectiles why wouldn't you?i believe the police use sp ammo because they can. i did have some hsm 223 ammo that was marked police ammo from memory it was 55gr sp. i use to work with an ex british paratrooper, we talked about the 223 round vs the 308 round a bit. he was saying the bullshit the were feed was if you shot someone with a 223 is less likely to kill them out right so it will take 2 people to attend to them/carry them hindering the enemy, where as if they a killed outright they will be left. like he said your not there to hinder your there to eliminated. if it wasn't for the ar15 platform surely we wouldn't have half the calibers we do, why people don't just buy the AR10 (believe thats the 308 version) and run 243 7-08 308 338 fed 358 win barrels with adjustable gas ports. |
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@ 09:05 pm (GMT) |
Martin TaylorRe: 6.8 SPCPolice and Special Ops teams use the Amax and similar with great effect in the Hornady TAP FPD ammo. Slows the high speed pass throughs in close quaters and also with longer range engagements.Did cost play a part in the 5.56....... l would like to think not but they would be a lot cheaper to produce than the 308 they replaced. I was told the following by an older solider years ago as a young cadet whilst on a range using the 308w SLR (FN), when l asked why the 5.56? To achieve higher fire rates (lower recoil), weapons could be made lighter (Barbie doll M16 were his words), followed by something like “F….ing big mistake, l would rather see controlled fire from one of these than squirting those bloody things everywhere, they’ve got nowhere to hide from these things” He then went on to tell me how effective the 308 was during Vietnam and how the enemy feared the OZ & NZ forces with their controlled fire power compared to the 5.56 armed forces. |
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@ 10:23 pm (GMT) |
Nathan FosterRe: 6.8 SPCMore correspondance:Hi ....., thank you for the 14 email replies, plenty of information to consider. It is my understanding that regular forces are bound to the Hague convention with regard to the use of FMJ ammunition. I did not know that the U.S military intend to use this cartridge on mass with a match HP bullet. Perhaps this signals the end of the Hague convention. With regards to use the of this cartridge for hunting: Please understand, we have shot hundreds of animals at extended ranges with the .270 Win. I am fully aware of how 110gr projectiles perform below 2400fps on game. I have also downloaded the .270 for youths to a muzzle velocity of 2400fps. I have been doing this since the the mid 1990's so it is not new to me. Yes, there is some merit in having a projectile that is somewhat heavier than the original .223 loads. But at the same time, I do not expect to see any major changes in performance in comparison to that which I have already seen when using the .270 at extended ranges with the likes of the 110gr V-Max / TAP. I can understand what you are saying about this cartridge being perhaps a better hunting cartridge relative to those who choose to use AR-15 rifles for hunting or culling. However, there are still factors to consider. For one, to make such bullets work at low velocities, the bullets must be somewhat frangible. On the other hand, a light weight frangible bullet can be problematic on tough animals. On the other hand, if we use a homogenous copper or bonded bullet (even if designed to work at low velocities), the bullet can struggle to initiate fast killing at low impact velocities. An example of this can be found in my most recent video on youtube (copper versus frangible) while my cartridges books goes into great detail with regards to the fundamental aspects of low velocity killing. So there are some limitations which need to be taken into consideration. As for deliberate bullet designs. Yes, I am well aware of this having worked first hand with some bullet designers. I can tell you that some of the people involved in these projects have not been jumping for joy at these opportunities. In fact, they have been pulling their hair out trying to make everything work. Even when a good projectile design was achieved, one manufacturer was left shaking his head wondering why the hell did we go down that track. More recently, I have been working with DRT, testing their .223 79gr bullet, designed for LE and hunting. The irony of this is (regarding the 6.8), with its high sectional density combined with mild muzzle velocities of around 2730fps in the AR- plus an optimal projectile design, this bullet has performed surprising well, offering an excellent balance of wide wounding versus reasonably deep penetration. This bullet cannot take a deer or pig tail on, but neither can the 6.8 with expanding projectiles. I have used this projectile out to ranges of around 360 yards and found that it still produces a relatively wide wound. Anyway, yes, I understand that a lot of effort has been put into optimizing the 6.8 for hunting. In plain terms, the cartridge can utilize varmint bullets at low velocities which can aid penetration while maintaining wounding capabilities. Such a combination can certainly work well. However, I do not want to see my readers drop their .270 Win rifles thinking that this is the next best thing. I see kids (16-18 year old young men) want to start out hunting but rather than buy a decent, accurate and potent bolt action rifle, they want a black rifle, not because of its prowess as a hunting tool, but because they want to play the soldier. The rifles barely group worth a darn in the hands of these young men. You will have heard them at the ranges, pop, pop, pop. These kids don't give a shit about humane killing (which is the primary purpose of our research). All they want to do, is rattle off a magazine load of ammunition as fast as they can pull the trigger. On the other hand- perhaps it is better that they do this with the 6.8 and expanding bullets rather than a .223 and FMJ ammo. So in this sense, your argument gains weight. On the other hand, an AR 10 rifle is even more effective and as our armed forces are finding with regards to military usage, it has been good to shift back to a full powered cartridge. I can see your point. Its just that this is not anything new to me. Like I say, I have hunted with youths using .270 downloads as a part of the NZDA youth buddy program and have used the .270 Win with full power loads out to ranges where performance is the same. It just becomes a bit of a farce when we see a pile of ballistics gel tests and so forth trying to portait X and Y factor when over a million people have been hunting with the .270 Win for decades and already know how it performs out at 300 yards etc. I get jaded by the marketing. But I do see where you are coming from and agree with what you are saying. Make of this whatever you will. Again, I can see your point so you do not need to try and drive this home any further, I understand where you are coming from. |
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@ 10:42 pm (GMT) |
Nathan FosterRe: 6.8 SPCBeyond this correspondance:Any of you who have used a .270 Win and light bullets out past a couple of hundred yards will know that it is mild yet effective. From this, one can see that the person who emailed me has a valid point when he emailed, suggesting that the 6.8 has merit as a hunting cartridge and as a youth rifle chambering. My initial (negative) response was based on the design of this cartridge with regards to FMJ ammunition. The person who emailed me states that this cartridge will be employed with HP ammo for military use which I cannot at this stage either confirm or deny as I have not taken the time to look into it. I just thought that you might all find this subject of interest. Other 'like cartridges' would include the .25-06 at extended ranges (impact below 2400fps), the 6.5's with varmint bullets at extended ranges and the 7mm-08 with varmint bullets at extended ranges. Shooting an animal at 100 yards with the 6.8 is much like shooting with the above gammut at 300 yards with lightweight bullets. Shooting an animal at 200 yards with the 6.8 is the same as shooting with the above at 400 yards while a 300 yard shot with the 6.8 is the equivalent of using the above at 500 yards. Obviously, these are very much over generalized figures but you get the picture. What I am trying to say, is that many of you will have some experience with light weight small bore bullets at these impact velocities and will know what you can and cannot get away with. Also, that these combinations do exceed the performance of the .223. The question is, does that make you want to ditch your high velocity cartridge in exchange for a black rifle chambered for the 6.8? Pros and cons. |
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@ 11:59 pm (GMT) |
Martin TaylorRe: 6.8 SPCThe question is, does that make you want to ditch your high velocity cartridge in exchange for a black rifle chambered for the 6.8?Why would anyone bother with this or a Whisper when as a hand loader l can easily match and beat these cartridges using reduced loads in any larger capacity 7mm, 270 or 30 cal along with a suitable projectile. Stepping up to full charge and heavier projectiles as skills & confidence grow. No need to buy multiple rifles, set the rifle up once in a suitable platform and watch the juniors develop! Don't hand load, easy, Hornady Custom Lite or Remington reduced factory ammo developed for juniors and light recoiling applications in 243, 270, 7-08, 7rm, 308, 30-06 and any of these would suit most youth hunting/plinking applications worldwide! As you said mate follow the money! |
@ 06:26 am (GMT) |
G DogRe: 6.8 SPCA litte of topic or maybe not.When I first got into hunting 10 years ago and was looking at buying my first rifle I spoke to a couple of older hunter on seperate occasions who didn't know each other. I trusted (still do) both there opinions. They both said either a .308 or a .270. None had a preference. I ended up with a .270 and its been my no1 hunting rifle since - ive played with other calibers out of interest and fir fun but I always stick with the .270 because its whst i know well, hasn't let me down. Pre deciding on what caliber and being green, I spoke to an experienced hunter at work and said to him - why are there so many different calibers around that are so alike? He just said it is what it is and people like change and new shit, but said the tried and true will always be around and be popular. .223, .243, .270 and the .308. I still don't understand the need for so many different cals except for the fact that its fun to tinker and improve things. |
@ 01:23 am (GMT) |
Mike DavisRe: 6.8 SPCok..#1 why.... cause I could buy it in Ruger mini 14 configuration #2 cause in that guise/rifle it would be shit hot for close bush hunting or popping of wallabies/goats etc I love my .223 bolt action and dropped a BIG red hind at about 40 yards yesterday no issue....right projectile=right range=right aim point. (Nathan you are a good influence) Slimjim over on www.huntingnut has done a heck of alot of testing of this calibre and his finding are interesting to say the least there seems to be a couple of barnes type projectiles made for this cartridge that outshine the others by a country mile no its not a .270 winchester but you could build it in short/med action if you are going to say its no good as a cartridge you best be selling that latte drinkers 7mm/08 using same logic and the 7mm waters even more so. no its not going to be a long range rifle proposition but if you wanted a ruger semi and didnt want 7.62x39mm or .223 or .44mag it would seem to be a good option (and looking at that list the most attractive) heck if I owned one I would still load it with heavy pills for bush stalking...130-150 grn partition anyone????LMAO |
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@ 11:51 pm (GMT) |
Mike DavisRe: 6.8 SPCI knew Id seen it somewhere.....issue #83 july/aug 2004 NZ Guns &Huntinghad article on this "flash new" cartridge and how it got started etc...looked good when first read,but when you re-read it the errors stick out.......funny the editor didnt pick up on it at the time claiming the velocity will be same as .308 at 600 yards then saying energy will be the same at 600 yards???????? ah hmmm 115grn vs 140ish grn I THINK NOT GENTLEMEN. also see back then in testing stage loaded with 115grn .277 hp match king projectiles at 2800fps yip the projectile selection has come a looooong way since then but trooper wont have the access to them that article also mentions the .223 delema with heavier stable bullets on Tailiban targets being described as "like hitting them with an ice axe" so the guys dug out older 55grn unstable loads.......... |
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@ 11:52 pm (GMT) |
Mike DavisRe: 6.8 SPCoops that should read ice pick...... |
@ 01:50 am (GMT) |
A VilavellaRe: 6.8 SPCHi,I am new to the forum and I don't know if I could add much more but I have experience with the aforementioned cartridges. The 6.8 is a very nice little cartrige. I have been shooting both the 6.8 and whisper for several years and in terms of terminal performance capabilities one cannot even begin to compare them because they are two different things. It would be like comparing a moped with a kawasaki ninja. Both might take you from A to B but they are two complete different vehicles with different engines and purposes in mind. The Whisper is a little case designed primarily for subsonic work, the other is a small intermediate cartridge designed to provide a decent balance between speed, trajectory and terminal performance also from light and compact carbines. IMO the whisper doesn't make much sense in the supersonic world. It simply doesn't have the powder capacity to propel even the lightest light for caliber 30 caliber bullets to decent speeds. But at the other hand it might be a nice alternative to the 30 carbine as close range defense or as special purpose round in subsonic mode. Accuracy in both auto-loader and bolt has been acceptable but nothing impressive. The 6.8SPC had a rocky start due to the inability from Remington to follow through but others had picked up on where Remington left and modern SPCII chambers and ammo are very effective and proven light carbines for many hunting applications like white tail, hogs and black bear. They are a bit on the light side for larger game but if the range is right is still a very potent round. I am impressed of the barnes 85gr and 95gr TTSX performance tested both reloads and some commercial offerings. Commercial 95gr TTSX from my 18" 5R AR carbine leave the muzzle at 2,850fps avg. / 869 m/s. FMJs are not allowed in most places and I would not even try them on any game no matter what purpose. As probably know the Barnes work as prescribed and are specially lethal in tough feral hogs when injected at fast speeds killing like lightning bolts . No matter the caliber and grain these bullets are very effective when used as designed. Speed kills. The 6.8 SPCII is a compact fast killing round for small/medium game and accuracy has been excellent in line with 223, 6x46 and even 6BR or 6.5BR rounds. I am giving this information from first hand shooting and hunting experience with these calibers. |
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@ 03:20 am (GMT) |
Warwick MarflittRe: 6.8 SPCHmmmm! So as a military round or if choosing one? What would you class the target species as? Light/medium, or heavy and Dangerous? Body armor changes the game too? Maybe Intelligent with a tendency to shoot back! Tungsten core copper FMJ projectiles maybe? Or should we not be talking about this horrid subject at all? Sticking to the paper Hunting and meat gathering topics instead? JUST SAYING! |
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@ 06:01 am (GMT) |
A vilavellaRe: 6.8 SPCThe 6.8 makes a lot of sense in a 16" carbine as a similar 6.5 or 7mm would. It gives a gain w/o going too heavy. My thinking is that if it was widely adopted the modern 6.8spcII or something very similar they would be leaning towards a fast moving 90-95grain bullet for the MBR and a 115-120gr for longer DMR and longer engagement range.But there would be several other alternatives worth considering I am thinking in the 6mm department. After all like Eugene stoner once replied to General Kalashnikov in one of the famous meetings of the titans: I had three requirements from the ARMY: 1) Weight 2) weight 3) Weight. They both got a big laugh. The same directives still apply today. Perhaps more than ever before. Operational combat load is at its max. and the armies will not sacrifice firepower. |
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@ 09:24 am (GMT) |
Thomas KitchenRe: 6.8 SPCI believe Eugene stoner hated the 223 round he invented the ar 10 for 308 when the army wanted the 223 he handed it over to Jim Sullivan and a team to get it to work. I'm away from a computer I'll post link when I get a chance.The caliber debate is an interesting one and will always go on. I do like how no one would try use 110grain bullets on deer in a 270 but they will in a 6.8spc. |
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@ 09:57 am (GMT) |
Mike DavisRe: 6.8 SPCThomas my good man you are mistaken...people DO use 110grn projectiles in the .270 on deer and have done so for years.one of the reasons it got reputation as a meat spoiler. myself I tried hornady 110grn fbhp but never tootooed enough to get them to group well, they were absolute dynamite on wallabies (10-40kgs) blew messy hole around 2litres in size,but the bruising/gelling/blood shock made using them for dog tucker not the best. a harder cup n core would have given same flat trajectory with less trauma and the110grn TTX barnes has a VERY good reputation in the .270 up to about 300 yards for fallow hinds/goats or young fellas/recoil sensitive shooters using a 110grn in .270 (if you can work out load that groups) makes a lot of sense...its sort of a .243/twoforfree/EBRG type loading |
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@ 03:49 am (GMT) |
Thomas KitchenRe: 6.8 SPCi think your right mike i am bit mistaken, most of the bullets are advertised as a varmint bullets thou, i got some 110gr vmax's i reload for light recoil for young shooters, not sure i would use them on anything but rabbits i have heard of people using them on deer but if you hit bone don't think they'll do much. now i got trail boss ill most like load that for the youngens.this is that video with jim sullivan i was talking about. https://www.full30.com/video/9b50f8a825ab510b4c227c7b32a76bc1 also another good watch https://www.full30.com/video/d0b180478fa3b4bd8508e317f240f80e bit off subject so if you need to clean up the thread Nathan feel free to remove any of my comments |
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@ 02:57 pm (GMT) |
A VilavellaRe: 6.8 SPCHi,The 95gr TTSX, 100gr and 110gr Accubonds among others are not varmint bullets and when delivered as prescribed they are lethal on deer, feral hogs, and black bear among other game. Bullets expand as designed, penetrate accordingly and have a proven track record. The 95gr TTSX is a lightning bolt and of course it could be injected and much higher speeds but at the average range in the northern woods normally withing 100m and rarely reaching 200-250 meters I see no problem. IMO the caliber wars are boring and pointless. It would be like arguing about mail carriers w/o considering the actual mail. The mail that is needed and how fast it needs to be at the destination are far more important discussions than the brand and uniform of the carrier. The 6.8SPCII (much better than remington's Ver.1) is a very nice little cartridge that can deliver that mail efficiently and effectively to different type of game. Here just a quick chart of the 6.8 SPCII with 95TTX from a 5R 18" carbine. http://www.doubletapammo.net/index.php?route=product/product&path=303_363&product_id=401 I like the 95gr to 100gr bullets because they deliver more with less. Many times less is more specially when trying to take advantage of every single grain of fuel in these little cartridges. Ballistic Coefficient 0.292 Velocity (m/s) 869 Weight (grains) 95 Maximum Range (m) 300 Interval (m) 50 Drag Function G1 Sight Height (cm) 5 Shooting Angle (degrees) 0 Zero Range (m) 200 Wind Speed (km/h) 10 Wind Angle (degrees) 90 Altitude (m) 0 Pressure (hg) 29.53 Temperature (C) 20 Humidity (%) 0.78 Ballistics Results RANGE (METERS) VELOCITY (MPS) ENERGY (JOULES) TRAJECTORY (CM) COME UP IN MOA COME UP IN MILS WIND DRIFT (CM) WIND DRIFT IN MOA WIND DRIFT IN MILS Muzzle 869 2325 -5 0 0 0 0 0 50 817 2054 2.5 -1.7 -0.5 0.5 0.4 0.1 100 767 1809 6.1 -2.1 -0.6 2 0.7 0.2 150 718 1588 5.5 -1.3 -0.4 4.5 1.1 0.3 200 672 1388 -0.1 0 0 8.1 1.5 0.4 250 627 1209 -11.2 1.5 0.4 13.1 2 0.6 300 584 1048 -29.2 3.3 1 19.5 2.4 0.7 |
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@ 09:15 pm (GMT) |
Nathan FosterRe: 6.8 SPCIf such discussions were boring and pointless AV, you would not have come up with a .358x39 and would be content with the parent cartridge.If the black rifle was not so popular, this cartridge would be put into the same class as a soft loaded .257 Roberts or soft loaded .243. Now imagine if I started telling people, that they really need to be downloading their .243's and 25's to get the best out of them. Nobody would buy it because as many folk know, velocity kills. hence why we want to take the 6.8 case and push it balls to the walls. This is a difficult discussion because it comes from different angles. The questions are: How do we get the most out of the AR15 platform as a military cartridge (primary). This then breaks down into a sub category question which is- do we use FMJ or an open point. (I still have no evidence as to whether this cartridge is to be used on mass with HP ammo. The second question is somewhat moot in that it becomes more about- How do we make this a viable hunting cartridge. There are two aspects to the 6.8 as a hunting cartridge. The first is that there is a push for sales and there has been a great deal of research to actually make the cartridge effective because- it simply is not a good performer without the right bullet. To this end, there has been a great deal of pressure on bullet makers. The second aspect is the demand from customers who like the AR15 and want to use it for hunting. I will say it again. If we took the AR out of the picture and started pushing the idea that downloads were the key to good hunting, nobody would buy it. I don't buy it. I have had quite a few bad experiences with low velocity small bores. But when we ask how do we get the most out of the AR15, we are then faced with quite a challenge including enhanced bullet designs to avoid the sort of problems that many of us have seen when using small bullets at low impact velocities. As an argument to my statement regarding poor performance of low velocity small bores, I have seen some good results with .270 and 7mm cal varmint bullets driven at mild velocities which allow the bullet to penetrate to a reasonable depth but also create wide wounds on light to mid sized medium game. Before I sign off, I would like to reiterate one major aspect which is always a concern for me- the money. I said earlier, follow the money and this still stands. When the 6.8 was first designed, there was no talk of hollow point ammo. What I saw was Remington FMJ ammo for military use- the primary role of the AR rifle. Based on this information and knowing that there is no real world difference in wounding performance between a 62gr 5.6mm bullet and an FMJ .270 bullet, my primary concern was that this was all about the money. I have seen so much in the way of marketing things we don't need these past so many years. This seemed to me to be the same, directed at the U.S military whom many folk treat as a money tree. My primary concern was for the allied soldier. They are not some consumer that we can just throw kit at and say "try this, its pretty cool". I think this is and will all come together over time but it will all come down to projectile designs, whether military or civilian. |
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@ 09:25 pm (GMT) |
Nathan FosterRe: 6.8 SPCHere is a question for my readers.I often come across two schools of thought. The first is- use just enough power to get the job done. This school of thought seeks minimum recoil and minimum cost while maximizing meat retrieval. The second school of thought is- use as much power as you can comfortably shoot. This school of thought is based purely around fast humane killing. Which school do you generally (doesn't have to be always) lean towards? |
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@ 11:30 pm (GMT) |
A vilavellaRe: 6.8 SPCHi,Wise thoughts but I think it is hard to put anyone in just two categories as many more factors can be part of the though process. This is the way I think about this when analyzing the situation with the small autoloader carbines. AR15 and AKM type of carbines are extremely popular due to alternatives, availability of parts and in the case of the AR15, its modular capabilities thus increased versatility. The AR15 as we know it today was scaled down and, for better or for worse, developed around the 223 cartridge and not the other way around. The weight requirements from the Army superseded any desire to implement a larger and more potent cartridge. A lot of people acquire ARs for recreation and home defense but they like to explore the alternatives w/o requiring complete new rifles and more for the occasional use and also having more power for hunting. Light carbines also attract more youths and relatives new to the sports that otherwise would be tormented by larger and harder to tame offerings. When exploring the alternatives and through the entire evolution of the AR15 we are constrained by the real state limitations we are starting with, specially max COAL as imposed by the magazines. There are special purpose alternatives like gated magazines and center stack magazines (only in 223 based cartridges) that might increase COAL up to 2.5" but most people want to use popular magazines for popular calibers already available like 5.56, 6.8 and 7.62x39/LBC/Grendel. When looking at formulas to obtain extra case capacity it is clear one cannot go longer so the only solution is to go wider. Going wider presents a series of challenges in terms of the bolt designs and materials used since all parts are limited to the maximum tolerances allowed by the original portfolio. If we go really wide we are talking about specialty calibers that require custom bolts, extensions and oversized receivers with a larger shank like the WSSM family. Limited firepower only reserve to special purpose like long range and hunting. To my knowledge the only two bolt designs that can run at top pressures are quality 5.56 and a custom bolt with the .473 (308w) bolt face aimed to the BR and BRX cases that requires a custom extension too but works with the standard shank and receivers. These are groups that have been taking the heat for several years even at 62K+ psi w/o showing stress nor breaks. The 6.8 has also been very reliable at the ceiling pressures that can be safely pumped in the modern SPCII chambers. At this point I am assuming most people are familiar with the specs and advantages of the reviewed SPCII chamber. Magazines that provide 2.3”+ COAL are the norm. The 7.62x39 and its siblings have been the ones suffering more from bolt failures and other complexities. Only recently we are starting to see improved bolts that do not break over time. Some alternative calibers like the 450 bushmaster, 458 Socom, and 50 Beowulf need to be run a very modest pressures to preserve brass and parts and prevent failures. The AR15 was created for the 223 and the 6.8 for the AR15 so we had the limitations imposed by the circumstances. The 6.8SPCII provides a substantial improvement over the 223 and 5.56 and specially in the shortest carbine barrels that are now popular with the 5.56 but far from ideal and a lot shorter than the AR15 and its parent caliber was designed for. In terms of the military applications and since weight continues to be the nr. one and most important requirement the 6.8 offers a substantial gain w/o sacrificing on firepower. But if we consider both the current requirements and shortcomings perhaps the ideal cartrige for the MBR would be a 6mm version not too different in dimensions form the 223 but with enough capacity to propel 80 to 90gr modern bullets to AR15 carbine speeds. This would be a 25-30% increase in momentum but what is more important could increase the effective range of the carbine to 700 meters and even past 800-900 meters for a DMRs. We are taking about shooting fast and flat enough to provide incapacitation and mortal wounding with alternative ammo and the proper terminal design for long range. In terms of the main bullet most likely would be of solid nature with arrowhead design or a thick SO-OT whit small lead core to reduce OAL yet good performance in hard and intermediate barrier. But both would be able to easily penetrate 1/4" cold rolled steel at 300 meters and show less deflection and more momentum on targets. Auto glass is another hard one specially with increased ranges of today’s battlefields. Speed is key here. Also all this is w/o drastically increasing the weight of the operational battle pack and sacrificing on firepower. The Chinese took a close look at was available and they decided to go 6mm. The round is not perfect but IMO a move in the right direction. Even the simple and popular 6x45 shows a significant improvement in performance using the same parent case and when loaded using nato/lapua brass and military primers at same nominal 5.56 pressures. This little cartridge makes hunting hogs and white tail possible where the 223 is not allowed by law and in terms of hunting bullet choices the 6mm starts where the 223 ends. This is still a cartridge with limitations but lets not quickly disregard the virtues of a stout 85gr bullet leaving a barrel at 840m/s. They are not a weed whacker like the 6mm/22-250, Dasher or other improved BRs but they do get the job done. The 6.8SPCII with solid 85-100gr delivers speed and lethal blows at decent ranges. If you are not familiar with these bullets give them a try. 110gr otms are extremely accurate at least it has been from some batches challenging the consistency of some bolt action rifles. I am talking about consistent and repeatable accuracy and not internet accuracy. The above are simple facts totally independent of our own personal preferences. With the imposed limitations it is impossible to find anything worth looking at larger than 7mm, I mean other than the thumpers and a couple of other specialty choices. The 7.62x39 and anemic whisper/blackout/etc.. can be fun but slow light for caliber choices are not going to get far in results other than internet sales perhaps. Speed is what gets the job done. |
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@ 11:32 pm (GMT) |
Warwick MarflittRe: 6.8 SPCThe second one for sure comfortably and accurately. |
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