Some questions on building a "scout rifle," - 6.8 SPC questions

[the naked prophet]

Okay, so I thought all this up in a dream. Seriously, I had a dream about Col. Cooper's idea for a handy all-purpose rifle.

I know that for an accurate rifle, a thicker barrel prevents the barrel from vibrating as much when the bullet comes out. A shorter barrel will vibrate less at the muzzle than a long barrel, and can therefore be made thinner (saving weight both by length and thickness reduction). So if we just go ahead and make the barrel 16 inches or so, that'll make the rifle pretty light and handy.

The .308 is commonly accepted as being a good scout rifle cartridge, mentioned by Cooper himself. However, in a short barrel like 16 inches, it loses a lot of velocity and has a bigger boom than I'd like. So I thought maybe 7.62x39 would work, since it's usually in 16 inch barreled AK rifles, but those ballistics don't hold well for longer ranges. So, maybe a caliber designed for shorter barrels, and designed to have a better BC than the x39, but still more powerful than the 5.56mm... how about the 6.8 SPC or 6.5 Grendel?

The ballistics of the 6.5 Grendel would be better, and feeding wouldn't be as much of an issue since it's a bolt action, but I think ammo availability is more important than the marginal increase in performance, so I'd go with 6.8 SPC personally.

Does anybody make a bolt action rifle in 6.8 SPC or 6.5 Grendel, or are both entirely AR-related cartridges?

Second, I haven't seen many modern bolt action rifles which can accomodate stripper clips. If I'm using a scout rifle, I want stripper clips. Does any manufacturer include slots to hold the clip, similar to, well, just about all military bolt action rifles and even the SKS?

Even then, it would need a scope mount located forward of the action. I think Ruger offers something like that, and hear rumors that Savage will soon.

I just want a bolt action rifle, chambered in 6.8 or 6.5, with a light 16 inch barrel, forward scope mounts, and the ability to use stripper clips.

Is that too much to ask?

 

[Hauptmann]

Remington makes several bolt action 6.8 SPC models in the 700 series. There is even a police model. Ruger now makes the Mini-14 in 6.8 SPC. There are no production non-AR rifles that are chambered in 6.5 Grendel. As far as I know, only Alexander Arms makes rifles in the Grendel which are AR types.

Personally, I would go with the 6.8 SPC if you are wanting a 16" barrel and are interested in shooting game under 300lbs. You should consider at least a 22" barrel for game up to 500lbs, or get a .308.

 

[Wes Janson]

It would seem to me that you're not going to gain anything by choosing 6.8 or x39 over .308 Win in terms of ballistics..and if the muzzle flash is an issue, you should look into having a flash suppressor installed.

 

[Charles S]

It would seem to me that you're not going to gain anything by choosing 6.8 or x39 over .308 Win in terms of ballistics

Agreed, but you could build a rifle with similar (albeit diminshed) ballistics in a much lighter and smaller package.

I personally think it is a great idea.

Let us know how it turns out if you decide to build.

 

[the naked prophet]

Was wondering how difficult it would be to rebarrel an SKS? Put on a 6.5 grendel barrel, use SKS stripper clips, trim off all gas piston related stuff, and have a straight-pull bolt action rifle, with less weight than an SKS and better ballistics?

 

[Zak Smith]

Both the Grendel and the SPC make the most sense in an AR-15 platform. As such, the capabilities the "scout rifle" is supposed to achieve are easily attained with the AR platform. Just a thought.

 

[GunTech]

For 6.5 Grendel, you have a couple of ideal options for converting. Both Remington (model 799) and CZ (CZ-527) have rifles chambered for 7.62x39. Do a rebarrel and voila! a 6.5 super light carbine. The CZ is a nice gun, and has a 5 round detachable magazine.

6.8 has a 0.422 inch case head, shared only by some obsolete Remington cartridges. For a bolt gun, it's pretty much just the 700 - a receiver designed to feed 308 length catridges and thus much bigger and heavier than necessay for the 6.8.

There have been persistant rumors that CZ was going to bring out a 6.8 527, but nothing so far.

 

[Gator]

"A Few Words on the Scout Rifle Concept

Since one must take care with one's speech it is appropriate that we address the issue of just what a "scout rifle" really is.

By the definition of the Scout Rifle Conferences held under the auspices of Jeff Cooper the scout rifle has been defined as a general purpose rifle suitable for taking targets of up to 400 kg (880 pounds) at ranges to the limit of the shooters visibility (nominally 300 meters) that meets the following criteria:

Weight-sighted and slung: 3 kilograms (6.6 lb). This has been set as the ideal weight but the maximum has been stated as being 3.5 kg (7.7 pounds ).
Length: 1 meter (39 inches)
Nominal barrel length: .48 meter (19 inches)
Sighting system: Typically a forward and low mounted (ahead of the action opening) long eye relief telescope of between 2x and 3x. Reserve iron sights desirable but not necessary. Iron sights of the ghost ring type, without a scope, also qualify, as does a low powered conventional position scope.
Action: Magazine fed bolt action. Detachable box magazine and/or stripper clip charging is desirable but not necessary.
Sling: Fast loop-up type, i.e. Ching or CW style.
Caliber: Nominally .308 Winchester (7.62 x 51 mm). Calibers such as 7 mm - 08 Remington (7 x 51 mm) or .243 Winchester (6 x 51 mm) being considered for frail individuals or where "military" calibers are proscribed.
Built-in bipod: Desirable but not mandatory.
Accuracy: Should be capable of shooting into 2 minutes of angle or less (4") at 200 yards/meters (3 shot groups)."

http://www.steyrscout.org/project.htm

Poodle shooters don't make the grade

 

[Titan6]

Not sure why it a bolt gun is prescribed. At times scouts need to send a high volume of of suppresive fire to break contact. I would likely pick an M6A2. That probably is the next weapon the US Army will go with anyway.

 

[HorseSoldier]

Yeah, Cooper was convinced not only that there was a market for a paramilitary bolt gun (edgy decision right off the bat), but that it also needed to be able to drop anything found in North America.

If I were building a Scout Rifle to go knocking around the North Slope of Alaska with, I'd consider .308 a poodle shooter round. If you're building one where your odds of meeting a brown bear are non-existant, and black bears slim to non, I don't see why a smaller caliber than .308 is not appropriate. Personally, I think Cooper missed the boat by not looking at 6.5x55 due to his fixation on basically updating the 1903A3.

 

[GunTech]

If the 6.5x55 was loaded to modern pressures, it makes sense. Otherwise, 260 is the same thing is a smaller package. By using a short action you can save some weight.

Cooper had some interesting ideas, but is the 376 Steyr really necessary for North America?

 

[HorseSoldier]

Not sure why it a bolt gun is prescribed. At times scouts need to send a high volume of of suppresive fire to break contact. I would likely pick an M6A2. That probably is the next weapon the US Army will go with anyway.

I feel like Cooper was not addressing the job I did back in the day as a cavalry scout with the Scout Rifle concept (our main concern with small arms was always ways to sling lots and lots of lead down range during break contact drills and ambushes).

His idea was a weapon that sacrificed volume of fire (he wasn't keen on semi-autos for the role, much less select fire) in favor of the lightest package possible, which he felt only a bolt action rifle could provide. He also wanted something that could mostly work the 0-300 range realm (if I remember right, been a while since I read his writings on the matter). If you take away the "able to drop a horse" angle, which is the only real reason .308 is required, he was probably describing CZ's 7.62x39 bolt carbine, really . . .

If the 6.5x55 was loaded to modern pressures, it makes sense. Otherwise, 260 is the same thing is a smaller package. By using a short action you can save some weight.

Yeah, the .260 would work as well.

 

[the naked prophet]

Both the Grendel and the SPC make the most sense in an AR-15 platform. As such, the capabilities the "scout rifle" is supposed to achieve are easily attained with the AR platform. Just a thought.

Can you really get under both the length and weight requirement with a scoped AR?

[edit]Just looked at Bushmaster's "SuperLight" carbine, the 16 inch with a telestock is 7.25 lbs loaded, then add a scope onto that. That's really pushing the boundary, and they don't offer it in 6.8 yet. The length looked good at 34-ish inches. I still think a bolt action could be done lighter, shorter, and cheaper, and just as effective with the exception of suppressing fire and CQB. [/edit]

 

[Zak Smith]

Not sure if you can make 6.6 lbs, but you're not going to make that with a "a thicker barrel [that] prevents the barrel from vibrating as much when the bullet comes out" on a bolt gun either.

 

[MatthewVanitas]

Has there ever been any explanation as to why Remington brough out the 6.8SPC in the 700 rather than the Model 7? That would have made a bit more sense.

As it is the .260 Model 7 keep shouting out to me, but I've never gotten into pig or deer hunting (well, nobody's ever taken me), so had no reason.

 

[GunTech]

You can build an AR that is really light - under 6 pounds.

Start with a Cavalry Arms polymer lower, then use a ABS carbon composite barrel. The Cav Arms lower will shave about a pound of you rifle alone. The ABS barrel is light but heavy profile and cuta another 1-2 pounds. But it is very expensive. You could build you rifle in any AR compatible caliber.

http://www.cavalryarms.com/MKII.html
http://home.alltel.net/mdegerness/prod01.htm

 

[Gator]

At times scouts need to send a high volume of of suppresive fire to break contact.

...Cooper was not addressing the job I did back in the day as a cavalry scout with the Scout Rifle concept...

...Cooper was convinced not only that there was a market for a paramilitary bolt gun...

Guys, military/paramilitary has NOTHING to do with Coopers Scout Rifle concept. It is a general purpose hunting weapon, a rifle you could always have with you that would handle both close in shots at moving game, and longer shots at stationary game.

It was never designed as, or meant to be, a military weapon!

I think Cooper missed the boat by not looking at 6.5x55 due to his fixation on basically updating the 1903A3.

Cooper had a fixation about updating the 1903A3? I don't know where you are coming from on that one. Cooper didn't do much work with A3s at all. They are unsuitable as Scout Rifles, obviously. Coopers first Scout was a Remington 600. The 600 has a short action, which was a requirement to make weight. That's one reason the 6.5 Mauser round wouldn't work, ammo availability is another, and the .308 is just so versatile, with a wide range of bullet weights and designs available.

 

[ECVMatt]

TNP, You read my mind..

I think a 527 in 6.8 would make a great Scout type rifle. It would be easy on the ears and shoulder, but still have a decent amount of power. I emailed CZ and asked it they were going to make the 527 in 6.8 and they said they would if interest warrented it. Maybe an email might be in order.

Since I couldn't get a 527 I bought a Rem 700 Tactical. I am not sure what makes it tactical, however it is a really fun gun to shoot. I shoot Rem FMJ and get groups about MOA. I also load up 90 grn HP's and get sub moa groups. They are going about 2900 fps and they smoke things like coyotes and jackrabbits.

I mounted a Leupold VXIII 2.5-8 in aluminum mounts and rings that are one piece. The whole gun is very light and the overall length is not too bad. With the scope on 2.5 I can use both eyes and still get a pretty good FOV. Not like my Ruger Frontier, but decent.

I am waiting for a 527 and as they make the .222 and other semi-strange calibers, I would hope they will add the 6.8. Then I can start worrying about how to mount a scout scope, ect, ect...

You might look into the Rem Tac in the mean time, it might come close to what you are looking for.

Matt

PS, sorry your thread got kind of jacked...

 

[HorseSoldier]

Guys, military/paramilitary has NOTHING to do with Coopers Scout Rifle concept. It is a general purpose hunting weapon, a rifle you could always have with you that would handle both close in shots at moving game, and longer shots at stationary game.

It was never designed as, or meant to be, a military weapon!

I think that is a fair assessment of what the Scout Rifle really is, but I think the entire concept was clouded from the start by calling it a "Scout" rifle. Unless he meant to reference Boy Scouts, the name has an obvious paramilitary feel and connotation to it.

Certainly if you read some subsequent writings on the topic (for instance Bob Cashner's Poor Man's Scout Rifle) I'd think you'd see that there are a lot of people out there that think, based on what Cooper had to say on the concept, that he was talking about a paramilitary/guerilla/militia rifle with the Scout Rifle concept.

Cooper had a fixation about updating the 1903A3? I don't know where you are coming from on that one. Cooper didn't do much work with A3s at all. They are unsuitable as Scout Rifles, obviously. Coopers first Scout was a Remington 600. The 600 has a short action, which was a requirement to make weight. That's one reason the 6.5 Mauser round wouldn't work, ammo availability is another, and the .308 is just so versatile, with a wide range of bullet weights and designs available.

Perhaps I should have been a bit more sweeping and said "updating the full-power military bolt action rifle for general service use, owing to his long-standing admiration for the M1903A3."

Same difference, really.

 

[Titan6]

I need to go back and read more on the intent of Col. Cooper.

But what is the OPs intent?

Military= You need the capability to suppress fire. The information you gathered is worthless when you fail to live long enough to tell anyone
about it.

Civilian= Scouting around and looking for game heavy dangerous game??? = Heavy Bolt Action in .308 or up...

Boy Scout? = .22 RF bolt gun

Cub Scout? = BB gun...

 

[Bigfoot]

You can build an AR that is really light - under 6 pounds.

Start with a Cavalry Arms polymer lower, then use a ABS carbon composite barrel. The Cav Arms lower will shave about a pound of you rifle alone. The ABS barrel is light but heavy profile and cuta another 1-2 pounds. But it is very expensive. You could build you rifle in any AR compatible caliber.

Yup.

But if yould rather have a .308 start with the 6 lb 10 oz BAR Shortrac, send the barrel off to ABS and put on a lightweight scope. Easily under the Col's weight limit. Even with that light weight due to the semi action it wouldn't kick much even with elk loads.

 

[GunTech]

Just to ad a note, I built a CZ-527 in 6.8 and for this to succeed, the factory really needs to do it.

To build a 6.7 CZ-527 you have to start with the 7.62x39 carbine, because the other versions don't have a large enough magazine to accomodate 6.8. The you will need a 223 bolt and extractor that can be opened up to 0.422 - the 7.62 bolt face is too big. Finally, you need a barrel.

By the time you are done, you could have bought two CZ-527s. 6.5 grendel is much easier, requiring only a rebarrel.

Of course, if CZ would offer 6.8 as a factory option...

I'm sending them email.

 

[ECVMatt]

I just found this on the net...

"So interesting morning. Yes, there are 2 loads available for the 6.8 available from Silver State Armory although not listed on their website, when ordering if you ask for their combat load you will get a hotter load. I asked if they had tested their combat load ammo in the new 6.8 spc Mini yet and was told no, not yet. John at SSA then directed me to Tim Hicks at Ko-Tonics a maker of 6.8 AR type rifles who specializes in the 6.8 and who is knowledgeable about the modified chamber for the 6.8 SPC. Check his link for more information about the modified 6.8 chamber. He told me that the barrel makers for the 6.8 spc will be using the modified chamber on the AR barrels from now on and were in the process of getting reamers and making the production change to the modified chamber, among them E R Shaw the barrel makers.
Here is what I was told about the modified chamber. No change to the cartridge itself all dimensions remain the same, also the same for reloading dies, no changes. Where the change is in is the leade or freebore area of the chamber. The original, and still current SAAMI specs put the rifling to close to the bullet when in the chamber, basically touching, when the round ignites it builds up pressure to fast, because of the initial resistance to the rifling and because the rifling shoulder was at 90 degrees to the chamber (lengthwise), it was found that by removing a very small amount of the rifling and angling it a bit, it allows the bullet to launch and exit faster without the build up of pressure, so you can load hotter and not build up excess pressure, that equals higher velocity. Ko-Tonics also goes with a 1 in 11 twist to reduce resistance from the twist rather the the 1 in 10, he is able to achieve 2650 fps with a 115 grn bullet in a 16" barrel with handloads. That is in a barrel with the chamber throat relieved. Also says that in his experiments with a thompson center in 6.8 that 18" is about the max length needed to get optimal velocity, so with the mini's 18.5" barrel thats good news, he says you can go 20" but you really don't gain that much in velocity.
I then called Pacific Tool & Gauge who makes the reamers for the industry. They confirmed what I had been told, cutting the throat a bit on the original chamber really improves the 6.8 and they do sell reamers that will do it. I was also told that they had just shipped a large quantity of the modified 6.8 reamers to, who else, E R Shaw. They have a standard reamer that will require a barrel removal for $139, or a Uni-Throat reamer that can do the job without removing the barrel for $99. Was told that most people could do it themselves, it comes with a complete set of instructions. I would call them and get into it a little deeper before I went and purchased the uni throat. It may be that removing the barrel and using the right reamer made for the 6.8 would be the best way to go.
Called SAAMI was told that no design changes had been adopted from the specs submitted by Remington in 2004, it calls for a 115 grn bullet at 2780 fps in a 24" test barrel with a chamber pressure of 55,000 psi.
Then called Ruger got a nice person, but like all front office types wasn't very knowledgeable, he said ruger would stand behind any ammunition used that was manufactured to SAAMI specs. I would assume that Ruger uses the original SAAMI chamber specs. So the question is still open on which chamber the mini 6.8 uses, I would assume that it is the original design short leade.
I'm wondering if when handloading setting the bullet a bit farther into the case might help accomplish the same thing? I'm thinking that there is a technique that I have heard of that lets you find out where the lands contact the bullet when handloading. Handloading is an area I am not familiar with.
The post from constructor said that "The reamer design only adds .050 to the throat", which ain't a whole lot. So it might be possible, like steve 4102 said, that you might be able to handload up to a higher velocity, setting the bullet back a bit might just do it.
If you can get 2650 fps from a 16" AR modified barrel then you should be able to get 2700 fps from a mini 6.8 18.5" barrel, that puts it into another class of cartridges and definitely one step over the Mini 30 in power and trajectory. Puts it up to a bit over 1850 ftlbs of energy, thats about 300 ftlbs more than the 7.62x39 thats starting to get there."

from here:
http://www.perfectunion.com/vb/showthread.php?t=59187

and this:

"Improved SAAMI-spec chamber and optimum 6.8 SPC rifling: We worked with the leading 6.8mm ammunition provider to US special forces, SilverState Armory. The chamber of the KT68 barrel is specifically designed to reduce excessively high pressure when firing high-performance ammo. Four groove rifling with 1:11" rate of twist increases velocity and also reduces excessive pressure."

from here:
http://www.ko-tonics.com/KT68.html

Know if CZ used this chambering method, we would really be on to something...especially with those numbers coming from a 16' bbl.

Matt

 

[the naked prophet]

Zak, I think you misunderstand. I'm not wanting a heavy barrel, I'm saying that to make a barrel lose less accuracy due to vibration, either a heavier barrel or a shorter barrel is necessary. Using a shorter, thinner barrel can get the same accuracy potential as a longer, heavier barrel, but save weight by reducing both the length and thickness of the barrel.

I wonder if you could get the rifle down to around 4 pounds?

 

[Old Trapper]

Right on Gator, and consider the 6.8 for a carbine

Gator has been studying the original scout rifle doctrine and offering an accurate and factual perspective of where Col. Cooper led the concept.

Cooper didn't live long enough to accomplish what he wanted with improving the modern carbine. While the 6.8 isn't a proper scout rifle caliber, it may become a good carbine caliber.

Let the military work out the bugs with their assault carbines, and we citizens can work on the idea of a versatile and practical carbine for the common man.

That will be quite a challenge if we are to make it handier and faster handling than the scout rifle. Perhaps the Ruger Mini14 in 6.8 is a good first step in that direction. But until 6.8 ammo is commonly available one could still argue for the .223 as a carbine caliber.