Ideal Calibers?

Most people on this board have their own opinions on the best calibers for rifles, squad weapons and pistols.
The discussion of the calibers has been going on in threads that might not benifit from it.

Most of us agree that no current rifle round is perfect:
.223 is underpowered
7.62x39 has a rainbow trajectory
7.62x53R has too much recoil for full auto on rifles and it's rimmed (bad for reliable feed in semiautos)
7.62 Nato (recoil is exessive for full auto in

Sure I will comment, on the fact I say .50 for pistol and nothing but bigger cal from there.

I like that Vintorez, need some factual info on it though.
That new OICW with the 20mm mag, that would be a blast.


NATO can bite a big one. They need to resign as well, and the UN can join them too. Let each nation build the calibers they want. If that was the case, the G11 would be more used I think.

More to follow.

The 6.8mm SPC and 6.5mm Grendel rounds seem promising.

THe Grendel doesnt drop to a supsonic velocity until 1400yards!

www.defensereview.com...

[edit on 19-4-2006 by warpboost]

7.62x39 has a rainbow trajectory

Not to be nitpicky, but no cartridge I know of rises after leaving the barrel, so a rainbow trajectory is not possible, in my understanding. Please correct me if I am wrong.

I have heard the 7mmX57 Mauser described as the perfect round for energy and ballistics, as well as the .270 Rigby, the US equivalent.

Other than that I'm with ADVISOR on this. Max it out!

Isn't the US working on a rifle that fires 7mm caseless ammunition?

7 x 43 is probably the ideal calibre. We worked this out in the late 40's but 'Uncle Sam' had to protect its arms factories so 7.62 NATO became the NATO standard (before the US decided it had to be 5.56)

en.wikipedia.org...

Strangely enough everyone's now coming 'round to our way of thinking

The Fins make really high quality weapons. Q. How do you get the 38 super casing to perform the role of sabot as the casing remains in the chamber?
Will you wrap the round with???what?

sayswho (skep by any other name)

The Sabot is attached to the bullet and will fly out the barrel, just like any other Sabot in existence. The .38 casing is only needed provide enough space between the bullet and the casing for the Sabot.

Originally posted by Icarus Rising

7.62x39 has a rainbow trajectory

Not to be nitpicky, but no cartridge I know of rises after leaving the barrel, so a rainbow trajectory is not possible, in my understanding. Please correct me if I am wrong.

You're not wrong.

The term is in use as a slang word to describe calibers with a lot of bullet drop.

Since a weapon is sighted in at a particular distance the bullet crosses the line of sight twice.

For a centerfire rifle sighted in for a 200 yard zero the bullet crosses line of sight on an upward trajectory at about 25 yards.
Then it crosses line of sight at the 200 yard mark.

After 200 yards you have to plot bullet drop from actual experimentation or for those who reload, consult the manuals for that load's actual drop.

A simplified example with the above 200 yard zero would be the bullet drops approx. 6" at 300 yards and 18" at 400 yards.

Since line of sight is straight and the flight of the bullet described as an arc, a bullet such as the above example would show an arc of large radius.
Very flat as the saying goes.

A heavier, slower, less ballistically efficient round that's zeroed at 200 yards, would drop perhaps 15" at 300 yards and 40" at 400 yards.
This last bit an approximation although the first example was taken from ballistics tables.

Viewing the arc of bullet flight of the 2nd example you'd see an arc of smaller radius, which to some resembles the arc of a rainbow.

And to add to the confusion, an experienced person can sight in a scoped rifle with one shot.

I get you. Its the bullet's path of travel due to the inclination of the barrel versus the line of sight to the target.

Sighting in a scope after one shot is a pretty good trick, the old one click equals a quarter inch at 100 yds extrapolation. You just need to be good with math, know your scope and your weapon, and be on the paper with the first shot, right?

One of the problems as I see it is that decisions on Cal. are being made by those having never experienced combat. One thread was correct in that too large a Cal. and the weapon becomes uncontrollable, too small and...well thats a no-brainer.
Having carried the M40A1 for 5 years, (at 14.5 LBS "approx.") I can tell you the weight of the weapon is critical in combat. Combat always involves long periods of running and hiking with your weapon so that just figures. Yet the NATO 7.62 in the right hands and the right weapon is extraordinarily effective at up to 1500 meters. (Yea a mile)
The lighter, smaller M16, 5.56 NATO is a good weapon, accurate (again in combat conditions) at over 800meters, again in the right hands.
I've also tried the Stoner 7.62 and liked the weapon but found it uncontrollable in full auto but very accurate at 1000 meters plus.
Anyway, my perfect squad/unit/platoon would comprise all of these weapons being used by those most effective with them, thus getting the best of all the worlds. In other words, coming from a combat vet, there is no magic cal., no magic weapon, no magic bullet, just good soldiers that if given the ability to choose a weapon that fits the mission will have an increased chance of survival.

Originally posted by Icarus Rising
I get you. Its the bullet's path of travel due to the inclination of the barrel versus the line of sight to the target.

Sighting in a scope after one shot is a pretty good trick, the old one click equals a quarter inch at 100 yds extrapolation. You just need to be good with math, know your scope and your weapon, and be on the paper with the first shot, right?

Correct about being on the paper with the first shot although that doesn't happen many times.
Due to most sighting in of scoped centerfire rifles is done at 100 yards.

You can go backwards on the ballistic tables and adjust the scope - once the rifle is sighted in - to approx 2" high over what the scope is aimed at.
That gives you a very close to right on the money at 200 yards.

Some flat shooters kicking out a high stepping bullet, say 3800' per second may be sighted in say 1 - 1 1/2" high at a hundred yards and other rifles shooting a heavier bullet at perhaps 2800 fps may be sighted in at 2 1/2 - 3" high and be close to right on at 200 yards.


The trick with the one shot sighting in is to set the target at 25 yards.
Shoot off a bench rest and aim for dead center on the target.
You'll want to use a target with 1" grids.

A rifle that's 2" high and 2" to the right at 100 yards will show 1/2" high and 1/2" right on the 25 yard target.
Just click in the appropriate adjustment on your scopes adjusters and a shot at the 100 yard target should be right on.

A useful trick to save ammo.
Seen more than a few times guys who were shooting at 100 yard targets take quite a few shots to just get on the paper.
If you don't reload and use factory loads, that can get expensive real quick.

Off the subject a bit from military rifles, but with military or civilian firearms accuracy is paramount.

My last rifle - purchased many years back - was a Ruger Model 77 bolt action heavy barrel in 22-250 caliber.
Scope was a Leupold 12 power.

First shot at 100 yards was 2" high - right where I wanted the elevation - and 1/2" to the right.
Interesting and it says a lot about the capabilities of modern firearm and scope manufacturers.


Getting back to the military caliber question, one reason the military went to the 223 was to lighten the load carried by riflemen.
308 (7.62 NATO) and the earlier 30-06 rounds weigh quite a bit more than the little 223's.

A second reason was that the 223 was fairly destructive on limbs and the thinking was that it was better to seriously wound an enemy soldier than it was to kill him.
Killing him took one soldier out of action.
Wounding him took three soldiers out of action because it takes a couple of guys to carry the wounded soldier and his rifle to safety and medical aid.

I think weight savings in the ammunition dept. will come from caseless or plastic cased ammo.
Some weight could be saved as well by developing a recoil-less rifle design and very lightweight materials could be used.
A 5# rifle is not out of the question.

Some competition rimfire (22 LR and the like) rifles are using carbon fiber barrels with steel liners.

My suggestion would be to go to 6mm (243 caliber) in a caseless round and fire it from a lightweight rifle.

You could raise bullet weight from the 223's about 55 grains or so to 85 grains in the 6 mm with minimal weight penalty.
The harder hitting bullet would still do maximum damage to limbs and such.

I understand the military has experimented with very fast moving bullets and launching systems.
On the order of 8000 fps.

Compare that with the considered pretty fast speed of the abovementioned
22-250 that launches at 3800 fps with reasonably mild powder loads.
Other civilian 22 caliber centerfire rifles launch at over 4000 fps, touching on 4200 fps at times.

There is a 204 caliber round out there.
It's pretty destructive on ground squirrels, prairie dogs, coyotes and the like.
The good part about it is that recoil is so mild you can remain on target after the shot is fired and see where it hits.
A decided advantage for a rifleman in a long range firefight.

Even so, if the 8000 fps designs ever see the light of day, it'll be a whole new world in the firefight area....


(Edited to add a missing line.)

[edit on 19-4-2006 by Desert Dawg]

From what I understand the .338 Magnum produced by Lapua (as per the Royal Marine Sniper weapon the Accuracy Inernational L96) has almost the same balistic characteristics as a .50 with almost the same range, less recoil, smaller firing signature, and it doesnt tend to over-penetrate like the .50. Seems like a good size for a sniper rifle.

The problem with the 7.62 NATO is that its damned heavy and has quite a recoil. Not to mention you're definately going to overpenetrate your target.

The 5.7mmx28mm round from FN has extremely good energy transfer characteristics, penetrates body armor but doesnt over penetrate flesh and has a muzzle velocity around 2300fps. Not a bad round. However it seems to lack long range punch and accuracy from what I've read.

Im interested in this 6.5mm grendel round.

Originally posted by Galvatron
From what I understand the .338 Magnum produced by Lapua (as per the Royal Marine Sniper weapon the Accuracy Inernational L96) has almost the same balistic characteristics as a .50 with almost the same range, less recoil, smaller firing signature, and it doesnt tend to over-penetrate like the .50. Seems like a good size for a sniper rifle.

The problem with the 7.62 NATO is that its damned heavy and has quite a recoil. Not to mention you're definately going to overpenetrate your target.

The 5.7mmx28mm round from FN has extremely good energy transfer characteristics, penetrates body armor but doesnt over penetrate flesh and has a muzzle velocity around 2300fps. Not a bad round. However it seems to lack long range punch and accuracy from what I've read.

Im interested in this 6.5mm grendel round.

Thanks Galvatron, I was wondering about the 5.7mm x 28mm round.

I was watching CSI Miami last night and one recovered round was described as a 5.728 and I couldn't figure out what they were talking about and figured it was a script error.

Supposedly fired from a P90.

Well as to the over penetration issue, the Marines at least issue Lake City, handspun, boattail Hollowpoints.
There will be instances of over penetration, but for the most part an excellent anti-personnel round

I was under the impression that the use of expanding bullets was prohibited under the Geneva convention. Are the Marines really using hollowpoints in combat?

FWIW, i am intrigued by a 6-6.5 mm round. slightly heavier than 5.56, less weight than 7.62, reasonably flat shooting..coupled with tungsten penetrator, match profile, it could be a very versatile round.

distance/anti-materiel, i still like the 50, api/fmj as needed...

subgun/pistol, the 5.7 might have applications here, but .45 hardball has taken down many a crazed enemy...

I tend to lean toward the 5.7x28 being a submachine gun round. Even though it has excellent energy transfer for its size, 180 joule after penetrating body armor, it doesn't have the sheer stopping ability that a .40 or .45 has. Which is why if you can spit a few of em out pretty quickly the 5.7 is a very good round.

However in a handgun where accuracy and rof is an issue, the 600 joule energy transfer of a .45 is i think more appropriate.

I remember hearing that the 5.56 NATO is overrated. IIRC soldiers complain, particularly spec-ops, that it takes 2 to 4 rounds to drop an enemy combatant, where as 1 was the norm with a 7.62. Sure one bullet from a 5.56 rifle is gonna incapacitate you, but not immediately, and if your head is all fizzy with adrenaline its going to take longer. Time you'd have to shoot some rounds.

I think a 6.5mm round sounds ideal. Heavy enough to drop a combatant cold, good range, less risk of over penetration (doing less damage), but light enough to carry an adequate combat load. SOUND GOOD TO ME!!

5.7x28 is a handgun/pdw/smg round, and it has exellent penetration but it's "soft" impact effectiveness has been doubted by Finnish Special Jägers (paras) who tested it with P90 (they allso said that P90 mags can't take low (sub -20C) temperatures.

.338 Lapua Magnum is a and accurate round (i've used it with Sako TRG 42 + Zeiss Diavari scope, used by FDF)
Its AP rounds do have exellent penetration, but it's not to be compared with .50< rounds in AMR role, It's accurate out to 1500m with factory ammo. And it's recoil is quite strong when compared to 7.62x53R (I shot the two during the same day) So it's a "middle class" weapon between light (.308) and heavy (.50-20mm) rifles.

7x43 round seems to be quite on the ideal spot, any ideas on the recoil from EM2? on Full auto?

That is because the P90s mags are cheap plastic, not plexiglass or some thing better. Manufacturers problem, after market products should take care of that.

When it comes to .45s, the 1911 for pistol or La France M16K, it has "better first round hit than most submachine guns" (closed bolt). Or custom De Lisle M4 "most silent of all silenced weapons.", all three do or can use ACP ammo in the DeLisle's case. The M4 is 7.62x51 NATO.

For long range what about a 15.5x106mm FN BRG-15 with muzzle velocity of 3460 ft/sec ave. Or 12.7x107mm Soviet Type77 (8 grooves, rh), with a muzzle velocity of 2625 ft/sec. Then there is the 14.4x114mm Soviet Gepard M3 (8 grooves rh), if you want a more accurate large caliber.
Those are for stationary or vehicle mounted, would be prefured, no one is going to want to move that stuff.

Source: Jane's ISBN 0-00-472453-4

I have seen a pistol, it was a 5.56 Bushmaster I think. 30 round mag and all, just very short, which made it concealable. Much like the LCW, but with out the customability.