6.8mm Stats

[Icelander]

Originally Posted by Anthony

No, because you haven't increased the weight of the weapon. Recoil is a function of bullet weight, bullet velocity, and weapon weight. 6.8mm increases bullet weight, reduces bullet velocity (but by considerably less than weight is increased), and doesn't much affect weapon weight; therefore it increases recoil. You could also generate stats by taking a 7.62 weapon, reducing damage by 1d, increasing ammo capacity, and reducing recoil to 2, but then you're dealing with an 11 lb weapon instead of a 7 lb weapon.

Recoil and Rcl aren't the same thing.

Rcl 2 is a minimum stat for any weapon that has a recoil at all. It does not follow that anything that recoils more than any given 5.56mm weapon must necessarily have a higher than Rcl 2.

Using that logic, an M4 would have to have a higher Rcl number than an M16, as it is a lighter weapon firing the same round.

A 6.8mm weapon would have higher than Rcl 2 if it was significantly more difficult to control on full-auto than the lightest 5.56mm weapons with Rcl 2.

I've not fired one, so I can't judge. But nothing I've heard or read suggests that this is the case.

In any case, the design goal is a weapon that can be used in the same tactical role as a 5.56mm weapon, but which has more punch. If the stats come out Rcl 3, that goal was not met and this round is a white elephant. As I said, I did not get the sense from HANS that he feels this to be the case.

[Anthony]

Originally Posted by Icelander

In any case, the design goal is a weapon that can be used in the same tactical role as a 5.56mm weapon, but which has more punch. If the stats come out Rcl 3, that goal was not met and this round is a white elephant. As I said, I did not get the sense from HANS that he feels this to be the case.

As far as I can tell, the military feels that the round is a white elephant.

[Icelander]

Originally Posted by Anthony

As far as I can tell, the military feels that the round is a white elephant.

I don't feel I have enough data to speak to that.

I know that they'll be hard put to justify the expense of replacing millions of weapons for a minimal improvement in performance, but that doesn't mean that they necessarily deny the possibility of such improvements existing.

[DouglasCole]

Originally Posted by Anthony

As far as I can tell, the military feels that the round is a white elephant.

Not precisely true. those who have used it feel it's quite satisfactory in its role: to provide more oomph out of the short barrels issued by Army and Marines than the M855 5.56x45mm.

"The Military" surely balks at having to replace half a million to a million upper receivers and 200 million rounds of ammo per year.

Especially since I just found out (though I'm sure this is old hat to many) the military just started issuing the M855A1 'improved' 5.56x45mm, of which the supposedly fired over a million of just in testing.

If we assume $300 per barrel assembly and $0.10 per round, that's probably approaching a quarter billion dollars over a five year period.

[AmesJainchill]

I don't think you'll see "The Military" adopt it...but law-enforcement, etc.

[jason taylor]

Originally Posted by AmesJainchill

I don't think you'll see "The Military" adopt it...but law-enforcement, etc.

Counterinsurgency is on the border between policework and war. It's difficulty comes from the fact that to few people recognize that it is on the border and must use a mixture of both paradigms-each at the right time.

But that complaint is a separate issue. The main point is that a lot of things that are useful in policework are needed for war because of the reasons given above.

[cosmicfish]

Originally Posted by Anthony

As far as I can tell, the military feels that the round is a white elephant.

Not true - I work for a defense contractor, and we've from some of their contracting guys that they like the round and the weapons, but it is mostly a timing issue - if they were contracting a whole new rifle right now then it would be a contender, but until then it is not enough of an improvement to justify a massively priced upgrade under a tight budget.

[jason taylor]

Originally Posted by Anthony

As far as I can tell, the military feels that the round is a white elephant.

As for that round, I couldn't say, but the military has an AWFUL lot of white elephants it could get by without.

I still have an animosity against the Seawolf. That is a Clancyvian tech-fetish and an awfully cool one to be sure. But we wouldn't dare use it in combat and anyway we already rule the waves.

Of course as we have only about half-a-dozen of those, why not take them home and use them as R&D labs? They can do useful work their and it would be just as well to have our R&D about a generation ahead of our actual force.

Who knows? We might actually discover Vilani on Barnard's Star, after all.

[Anthony]

As a side point, I only listed it as Rcl 3 if used in a converted 5.56mm weapon. Such as what the OP asked about.

Some basic math here: the recoil inertia of a round is mass*velocity (plus a certain amount for escaping powder, which is difficult to measure here but will generally scale fairly well with the round weight so you won't go too far wrong by ignoring it unless there's a very large difference in muzzle velocity)

5.56mm: 4.0g * 940m/s = 3.76 kg*m/s.
6.8mm: 7.45g * 800m/s = 5.96 kg*m/s (+58% vs 5.56)
7.62mm: 9.7g * 850m/s = 8.24 kg*m/s (+38% vs 6.8)

As we can see, the 6.8mm is much closer to the 7.62mm than the 5.56mm. However, this also isn't the number we particularly care about. What we actually care about is either the recoil velocity (which will scale with recoil momentum / weapon weight) or recoil energy (which will scale with recoil momentum^2 / weapon weight). Most likely we care about the first, the second should more affect Min ST.

So, the default 5.56mm from Basic is a 9 lb (4 kg) weapon, which appears to be a loaded M16, the default 7.62 is an 11 lb (5 kg) weapon, which I can't immediately identify. We thus get a recoil velocity of:
5.56 from AR: recoil velocity = 3.76/4 = 0.94m/s.
6.80 from AR: recoil velocity = 5.96/4 = 1.49m/s (+58% vs 5.56)
6.80 from BR: recoil velocity = 5.96/5 = 1.19m/s (+27% vs 5.56)
7.62 from BR: recoil velocity = 8.24/5 = 1.65m/s (+11% vs 6.8/AR, +38% vs 6.8/BR)

The 6.8mm from an assault rifle is obviously much closer to the 7.62 than to the 5.56, so it's pretty fair to call it recoil 3 (though it should have a lower ST). 6.8mm from a battle rifle is less obvious and can reasonably be argued to be recoil 2. 5.56mm from an M4 carbine (6.9 lb loaded) would have a recoil velocity of 1.23 m/s.

[DouglasCole]

Originally Posted by Anthony

So, the default 5.56mm from Basic is a 9 lb (4 kg) weapon, which appears to be a loaded 5.56 AR, the default 7.62 is an 11 lb (5 kg) weapon, which I can't immediately identify.

Figure it's a G3 or L1A1, both of which I believe are about 11lbs loaded.