Optimum Military Rifle Caliber -- 250 Savage?

Status
Not open for further replies.

Badger Arms

New member
I'd like others opinions on the optimum military rifle caliber and loading. Now, let's forget about the current climate and think back to, say, just after WW-II where we COULD have chosen a caliber and possibly even a rifle that would have lasted through the decades. Take into account the following factors:

1: combat effectiveness to include accuracy, trajectory, terminal ballistics.

2: practical usefullness to include weight of loaded cartridge, combat load, and recoil.

3: economy in terms of unit cost, development cost, and adaptability to many different weapons and situations.

My vote: 250 Savage sending an 87 grain boat-tail bullet out at 3,000 fps from an 18 inch barrel. Bullet design should be similar to the SS-109 and steel cased. Here's my logic:

The 250 Savage is a proven round effective on deer and with enough field time to prove the design. It has mild enough recoil for quick follow-up shots and controllable full-automatic fire. You can chamber it for carbines, rifles, LMG, and Heavy Machineguns without the need for two calibers as is now required with the 5.56x45 and 7.62x51. A reliable and bright tracer can be made in a .25 caliber round. Steel cases bring down costs.

For guns, I like the HK-36 design for the carbine, rifle, and LMG versions (with a heavy barrel). The current FN-MAG is a fine weapon and could probably be lightened up considerably for use with the 250 Savage.

Consider that had we adopted this caliber, we wouldn't have gone through the "Goldielocks" syndrome where the .223 was too small and the .308 was too big. Neither was ever wholly adequate. We HAD a good design in the T-48 rifle that far outperformed and outproduced the compromising M-14 and even McNamarra's folly.

---
Sidenote and History lesson: The FAL (known in Army Test Nomenclature as the T-48) was tested and found superior to the M-14 (T-44). Instead of taking the logical step of adopting or improving the better weapon, the politicians running the Army chose to continuously improve the inferior weapon for five years until the final incarnation performed up to the same standard as the FAL. Remember also that the M-14 was itself the result of a lengthy and expensive improvement program that began with John Garand's first test rifles in the Late 1920's(?). Had the FAL been improved in the same fashion during that period, a superior design WOULD have emerged. Alas, Politics won out and the M-14 turned out to be merely adequate.
-------
 
6.5-08. Better bullets. More velocity and better for GPMG use than 25 caliber, roughly similar weight. I would use 120gn steel core for general issue and GPMG use, and 142 Sierra MK's or 140A-max for the sniper rifles. In a pinch you will be able to find ammo for your sniper rifle from anybody and steel core AP has always been more accurate than ball or Semi-AP(SS109/M855) Also greater bullet weight means better effectiveness for you MG use. High sectional density means that it may be able to defeat targets that withstand 7.62 ball(class III armour) I like the FAL idea, perhaps updated for optical sight use and better metallurgy. Semper Fi...Ken
 
Funny you should bring this up. This month's Infantry Magazine has an article entitled "Is 6mm the Optimum Caliber? A Common Cartridge for Rifle and Machinegun" by Stanley C. Crist.

The author suggests a 100 grain bullet with a ballistic coefficient as close to 0.54 as possible. I'll quote from the article: "One caliber--the 6mm Optimum--could do it all. A weapon sending a 100-grain very low-drag bullet down range at over 2900 feet per second would give snipers the flat trajectory of the .300 Winchester Magnum. And it would give machinegunners the penetration potential and tracer capability of 7.62 NATO, thereby permitting the development of an infantry machinegun light enough to replace both the 7.62mm medium machinegun and the 5.56mm squad automatic weapon. The 6mm Optimum--being a compact, light weight cartridge, with low recoil impulse--should also allow the creation of a combat rifle that is little or no heavier than the M16A2."

It sounds good, but nowhere in the article does Mr. Crist address the terminal effects of this magic round. Will it be the close range manstopper the 5.56mm is or will it punch nice neat holes?

Jeff
 
Well, the big question is...

What do each of those respective rounds cost?

Also, what are the dimensions of those rounds? What is the powder amounts used in each?

------------------
The Alcove

I twist the facts until they tell the truth. -Some intellectual sadist

The Bill of Rights is a document of brilliance, a document of wisdom, and it is the ultimate law, spoken or not, for the very concept of a society that holds liberty above the desire for ever greater power. -Me
 
I've often thought the .243 would have been a good choice. Mild recoil and more punch than the .223. Also, the 100 gr. .243 bullet should outperform the 62 gr. .223 at distance in wind. Cost of manufacture and weight would be slightly more but not enough to cause a stir.
 
I do believe that the 260 Remington is a 6.5mm incarnation of the 308. This is also a good round but it's a bit more powerful than the 250 Savage. I'd be splitting hairs to say it wasn't in the same class though. I think that the key here is that this round should be given the same level of improvement in projectile design that the .223 and .308 have enjoyed. A VLD .25 bullet might be able to reach a .5 BC, but that might very well be the top end limit when velocity is kept at a reasonably high level.

Jeff, I'd love to read that article but have never heard of the magazine? Where can I get a copy?

Anyhow, I think a BC of .54 is a little too much to ask for out of a 25 or even a 6.5 caliber. There's only so much Ballistic Coefficient you can squeeze out of such small calibers. Still, I think BC's approaching .5 are much better than the .307 of the SS-109 ammo. Down-range energy and effectiveness should be greatly enhanced.
 
BC for the 142 MK and the 140 A-max are well over 0.550. 120gn bullets are going to be right around 0.500 with any sort of decent design. Looking at velocities of around 2600-2650 for the 140's from a sniper rifle, same for a GPMG. 120's should be right around 2750-2800 from a 20inch barrel. weight is going to be a little less than 308 ball ammo, so weight is an issue. Steel core so the bullet isn't going to do anything crazy like the M855 is supposed to do(but doesn't at long range or from the M4) but it makes nice holes through people and things. Also the 6.5-08(260 Rem) is inherantly very accurate and doesn't eat barrels near as fast as the 243Win. Burns about 45gns of powder, likes 4350 and 4831 speed stuff. Semper Fi...Ken
 
saw6mm.jpg

6mm SAW & .223

Sounds like your describing "the best cartridge that never was"....the 6mm SAW. In the early 70s the military spent a great deal of time and money developing a cartridge called the XM732 BALL (aka 6mm SAW). It was intended to be used with the (then experimental) Squad Automatic Weapon (SAW). SMALL ARMS OF THE WORLD, 12th Edition, by Ezell mentions the 6mm SAW briefly as it covers the development of the SAW machinegun in some detail.

The 6mm SAW was not derived from 5.56x45 or the 7.62x51 (or any other cartridge case for that matter), it's case dimensions were totally unique. According to CARTRIDGES OF THE WORLD, 8th Edition, by Barnes the OAL of a loaded round was 2.580". The case had a .410" head dia. and was 1.779" long. It was loaded with an extremely streamlined 105 gr bullet that moved out at 2520 fps from an 18" barrel, not that far behind cartridges like the .243 Winchester and 6mm Remington.

One interesting facts about the 6mm SAW is it was the first cartridge to be designed by computer. The technique called "parametric design" was a complicated model of complex thermodynamic equations. Pretty cool stuff if your an Engineer or a gun nut. The Army wasn't that impressed and once they figured out how to make tracers work in .223 caliber bullets they dropped the 6mm SAW in favor of the POS 5.56x45. To bad in my opinion, the 6mm SAW had a lot going for it, and in civilian form the brass would have been the basis for many, many interesting cartridges that never will be. -- Kernel
 
6mm SAW looks like a bigger version of the 5.45x39 Kalashakov..

------------------
The Alcove

I twist the facts until they tell the truth. -Some intellectual sadist

The Bill of Rights is a document of brilliance, a document of wisdom, and it is the ultimate law, spoken or not, for the very concept of a society that holds liberty above the desire for ever greater power. -Me
 
How obtainable/expensive is 260 remington?

------------------
The Alcove

I twist the facts until they tell the truth. -Some intellectual sadist

The Bill of Rights is a document of brilliance, a document of wisdom, and it is the ultimate law, spoken or not, for the very concept of a society that holds liberty above the desire for ever greater power. -Me
 
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Dangus:
How obtainable/expensive is 260 remington?
[/quote]

It's a new caliber offering by Remington. In mass-production arsenal situations, it should be nearly as expensive as the 308 or moreso with a well-designed bullet akin to the SS-109.

I'd like to state that 2500fps is very slow with a 105gr bullet out of an 18" barrel when compared to the .243. With Factory 100 grain bullets, I was chronographing 2850fps at 10' from the muzzle. (Remington 788 carbine) The 6mm SAW explored many technologies like VLD bullets, Aluminum and Steel Laquered cases, and computer design. The problem is, when the same technologies are applied to current calibers, similar levels of improvement can be obtained. I'll say that the SS-109 was given a significant amount of attention and development and may well be the pinnacle of .223 ammunition development in realistic terms.

I am of the opinion that the 6mm SAW lacked the velocity required to perform long-range work. Bullet drop at extreme ranges makes range estimation very critical for sniper work. Further, any gains foreseen by the VLD bullets were lost with the corresponding drop in inital velocity that they sought fit to impart.

As far as velocity goes, for general-use, a velocity of between 2700 and 3000 FPS with a VLD bullet out of an 18-20" barrel would provide the most utility. Beyond 3000 FPS, carbines would begin to suffer greatly in the velocity area and muzzle blast becomes a major problem. Below 2700, I feel that you are sacrificing mid and long-range effectiveness for bullet drop considerations. I prefer 3000 fps because of the hydrostatic effects of the projectile in flesh that incapacitate much quickly than clean holes. IMNTBHO


[This message has been edited by badgerarms (edited August 26, 2000).]
 
6.5-08 is going to cost the same or a bit less than 308, which is to say not much. Ammo costs are the smallest part of the deal. I would alter the 260 case slightly and shorten the neck and blow the shoulder forward for more capacity. VLD bullets are the way for long range performance. BC is much more important than velocity for long range perfomance. which is why it's always better to go to a heavier bullet for long range work than to try to up velocity. Something in the 2600-2900 range is more than adequate given good bullet design. 6.5 bullets are big for good wound ballistics regardless of bullet design, but given the inherant instability of VLD designs I think that they will be more than effective enough for our purposes here. A monobloc projectile will not rupture like the composite M855 but will penetrate far better as well as be cheaper to produce. I also like the idea that you will need only minimal retooling as brass can be drawn from 308 cases and head dimensions are the same as 308. I dislike introducing new head sizes into the game. Mag capacity will be the same as 308. And the same links can be used for MG purposes. An all around good deal. Now if we can just get the Pentagoon idiots to transfer some money from the OICW project..... Semper Fi...Ken
 
Badger, I think you make my point. The 6mm SAW with a 5% heavier bullet offered velocity only 12% less than the significantly larger .243 Winchester. So you have a compact cartridge only slightly larger than the .223 (actually the 6mm SAW and the .223 have the same case length - 45mm) that allows performance in the same league as the "full size" .308 family of cartridges. To my way of thinking that's a major breakthrough in cartridge design.

In the real world it would have meant an infantry man could carry 50% more 6mm SAW ammo (vs the same weight 7.62x51) in a weapon that weighed less than a M60 but provided performance comparable to the M60 (especially when compared to the weak sister alternative - the 5.56x45), plus about 1/2 the recoil & flash and better controllability. The next logical step would have been to develop a M16 chambered in 6mm SAW, a task that would have posed no major technical difficulty. Then we would have had something.....

My gripe is since the Army killed the 6mm SAW it never trickled down to civilian shooters. That cartridge would have been just the ticket for a lot of experimentation and applications from varmints to medium game, especially when chambered in civilian semi-auto rifles like the Mini-14, Browning BAR, and Remington M742. Chambered in the T/C Contender it (and it's wildcats) would have been the ultimate choice for single shot pistols. -- Kernel
 
What's the muzzle velocity average on the 260 remington? Someone may have said it here, but I must have missed that.

------------------
The Alcove

I twist the facts until they tell the truth. -Some intellectual sadist

The Bill of Rights is a document of brilliance, a document of wisdom, and it is the ultimate law, spoken or not, for the very concept of a society that holds liberty above the desire for ever greater power. -Me
 
BTW, any opinions on the .270 Win?

------------------
The Alcove

I twist the facts until they tell the truth. -Some intellectual sadist

The Bill of Rights is a document of brilliance, a document of wisdom, and it is the ultimate law, spoken or not, for the very concept of a society that holds liberty above the desire for ever greater power. -Me
 
I think the .270 would be better choice for the M-1 Garand than the 30-06 was. In the field, it provides a flatter trajectory with lighter bullets and recoil. It is a VERY long cartridge though and semi-automatic and automatic guns chambered for it are correspondingly larger also. The question would arise as to why not just stick with the 30-06?

In any case, the only other option for the M-1 Garand was the 276 Pedersen. This round was somewhat less powerful only slightly outperforming the 7.62x39. For the tactical doctorine of the time, it would certainly have been a good choice. Overall Length was comparable to the .308.
 
Badgerarms,
Infantry magazine is a professional bulletin published by the US Army Infantry School at Ft Benning. It is published quarterly and they do sell subscriptions. It is $15.00 for six issues and $28.00 for twelve issues. Write to Infantry PO Box 52005, Ft Benning GA 31995-2005.

I don't know if a good library would have it. It's rather long to post here, but if you e-mail me off line I'll arrange to get you a copy of the article.

Jeff
 
Badgerarms: I wuz just reading through the new SOF. .30-'06? A comment in SOF said that there have been complaints aabout recoil from the M-16!

I won't comment further.

:(, Art
 
260 Rem is doing about 2600fps from a 22inch barrel with 140's. 120's are doing about 2800 from same. 270 would have been a far better choice than the 30-06 for the Garand except the pressure rating of the Garand which would not have handled the 270's 52,000cup pressures. I don't like the 6mm SAW idea, it would be fine for an assault rifle but not adequate for a GPMG. It also has too long a neck, all that wasted powder space! I also think it would have sucked as a commercial round. Face it, 243 is already marginal for deer. By throttling back the velocity it would only get worse. Yes, there are people who seem to find the need to use inadequate calibers on deer. Case in point, look at all the people who proclaim the advantages of 223 and 22-250 on deer. I think it's silly. Anyway back to the cartridge, I think that we could eliminate the three round burst concept. It's useless, a fast double tap is much better. So we basically have the SLR in 6.5-08. Perhaps my version, the improved case with shorter neck. Either way. GPMG's have to deal with both semi-hard and soft vehicles at ranges up to 1000m, so you need plenty of gun. At the same time the rifle needs to be light enough to transport as well as rounds light enough to carry. You could carry 200 rds of 6.5-08 as basic load and it would weigh roughly twice what 5.56 weighes. But it would still be less than what 7.62 weighes so I guess it's a toss up. Maybe if we had optical sights we wouldn't need quite so many rounds? Training wouldn't hurt either. Semper Fi...Ken
 
EchoMikeFive, the last thing you'd want to do is put a shorter neck on the .308 (or derivative) case! The neck is to short already, making it shorter would be a big mistake. Take a look at the 6mm SAW picture. It's got a long neck for a reason, the Army put it there to specifically address an intrinsic problem found in the .308 and .223. - necks to short to provide enough tension to properly secure the bullet.

Neck tension is not a big deal in slow fire civilian rifles, in fact some target shooters make ammo with virtually no neck tension - finger pressure alone will push the bullet back into the case. However, machine guns may jam, fail to cycle, or spontaneous disassemble (i.e., blow up) when fed a bullet that's pushed back into the case. Heavy crimping (which is what we do now to correct the problem with the 5.55 & 7.62) isn't entirely satisfactory since it causes another set of problems.

Blowing the shoulder forward won't gain much anyway, VLD bullets are so long they extend back into the case and displace most of that extra volume. In an optimally designed case (like the 6mm SAW) the shoulder begins exactly where the base of the bullet ends - that gives maximum accuracy and efficiency.

The .260 Remington is a great cartridge. I think it may be the best whitetail cartridge around. I especially like the first version that came out in 1892 when it was called the 6.5x55 Swedish. Unfortunately the laws of physics apply and cartridges like this are just to powerful to be controllably shot offhand in full auto from a shoulder arm that weights less than 12 lbs or so.

So where are we? We all seem to agree the mythical OMRC lies somewhere between the .50 cal and a Daisy BB gun that's been pumped nine times. By all accounts the .308 was to powerful to shoot full auto from large 9 - 10 lb battle rifles like the M14 and FAL. The .223 IMO is barely adequate for ground squirrels, how the military got saddled with that turkey I'll never understand. Somewhere in between there is gotta be a compromise that with allow one cartridge to meet both the requirements of an assault rifle and squad automatic weapon so fire teams can carry one common round. -- Kernel
 
Status
Not open for further replies.
Back
Top