Greets,

I was wondering what kind of damage code would be on on large bore sniper rifles, basically modified autocannons. I would be looking at clibers in the 12.7mm, 20mm, 25mm, 30mm, and 40mm range.

The purpose is to find a rifle which can effectively punch through the engine block of a limousine at distance, or used to fire on a passenger at an oblique angle inside of said armored limousine.

The 40mm Bofors round might be too much. What do you think?

i would say compare you idea to the barret and stage it up from there until you think its suitable.

You can get bigger than a Barrett?

I would already consider the Barrett to be a 12.7mm, or .50 BMG. The Panther Assault Cannon has always been 20mm in my mind, so that would be a good place to start.

Does 4th Edition still have the Victory and Vigilant Rotary Autocannons? Those would be good choices for 20mm and 25mm, respectively.

As was adeptly pointed out to me in THIS THREAD (Thank you CrusherBob), by modern definitions a cannon is anything that fires a round 20 mm or larger on a relatively flat trajectory in a direct fire fashion. By that definition a 20 mm anti-tank rifle basically = the SR assault cannon. I'd argue that the GM Light cannon is roughly equivalent to a 25 mm Bushmaster and that the GM Heavy Cannon is roughly equivalent to a 40 mm Bofors. (Note that "Heavy" in an Arsenal sense does not include very large main guns like the Rheinmetall 120 mm on an M1A1, which will presumably be including in the forthcoming military/mercenary source book).

SO the break down basically looks like this:

20 mm = 10P
25 mm = 13P
30 mm ~ 15P
40 mm = 17P

You can mount a scope to anything...

In real like, Carlos Hathcock mounted a scope to a Browning M2 .50BMG machine gun, and was using it to snipe at some pretty extreme ranges.

Scoped Browning M2

Carlos Hathcock

I already assume the sniper rifles with a higher damage code are .50 or similar. Those are the sniper rifles today that you don't (according to the Geneva Conventions, I believe) shoot people with. They are generally anti-material sniper rifles. The "sniper rifles" that are bigger are autcannons (cannon, recoiless rifle, 'uge sniper rifle, whatever you wish to call it).

Incidently in RL I believe they are developing a 20mm anti-material sniper rifle. Of course there is also a .50 assualt rifle out there also (and .51 pistols). *looks like he's going to cry from happyness* The world is such an amazing place.

Well I learned something new.

Link
Link
Link

For size comparison (since I happen to have these sitting on my desk... yes I'm weird):
Link

{edit to fix link}

I kind of like this one...

Vulcan 30mm

I think I've got a .50 caliber and 20mm projectile floating around. I'll see if I can get a picture to go along with your cases.

We could always go with the 15.2mm death machine known as the Steyr IWS 2000
http://world.guns.ru/sniper/sn46-e.htm

40mm of steel from 1km away....

Sorry kids, your body armour doesn't mean shit anymore.

EDit: Yeah, this is a gun for trolls and people who don't mind shooting from prone. At 1.8 meters long, it's a beast.

I assumed Chrysalis wanted a man (or at least troll) portable anti-material weapon. This is a great illustration of how I envision the Vigilant or Vanquisher Autocannon tho...

Zombayz: Lovely!!

Depends on how well the limo is armored.

Assuming it is armored vs rifle fire (~15mm RHA equivalent, around armor 12-15 in SR 4 terms):

12.7mm will have adequate penetration to around 750 meters; if fired in bursts instead of single rounds, it will probably stay effective a few hundred more meters.

for 14.5mm probably effective to 1000+ meters

for 20mm, around 1200? meters

for 25, 30, and 40 mm, probably 2+ km, assuming you are firing bursts out of an autocannon

25mm and 40mm grenades will also be effective out the the max point target range of the grenade launcher, the problem will mainly be in actually hitting the target.

For 25mm high-velocity grenades, maybe 1000 meters
For 40mm high velocity grenades, maybe 750 meters
for 25mm low velocity grenades, maybe 200 meters
for 40mm low velocity grenades, maybe 150 meters

If firing grenades in bursts, add around 50% to the effective range vs point targets.

I think the 30mm is severe overkill for even the Vigilant or Vanquisher.

I've always pictured the Vengeance or Vanquisher as being a .308 & .30-06 caliber mini-guns respectively, at least according to 2nd and 3rd Edition damage codes. The Vanquisher being a .30-06 is debatable, as not many modern armies field that caliber in a machine gun anymore, but it's either that or 7.62x54R, based on modern comparisons. I don't feel that you start getting into .50 BMG territory until you reach the Barrett.

I have no idea what they've changed to in 4th Edition, though...

As for the Victory and Vigilant Rotary Autocannons, here's what I picture them as:

Victory = 20mm Oerlikon

Vigilant = 25mm Bushmaster

As for a size comparison between the .50 caliber and the 20mm:

.50 BMG vs. 20mm

This second photo shows from left to right: .22 LR, .223 (5.56 NATO), 7.62x39, .308 (7.62 NATO), .50 BMG, 20mm Practice Round, and what might be a 20mm Dummy Round.

Multiple Caliber Comparison

This last photo shows the actual rifle cartridges compared to the .50 caliber and 20mm projectile:

Cartridge Size Comparison

I would just treat it as a Sniper Rifle with 33% added to each range bracket and Panther damage.

Why add range? Why not just treat it as a Panther Cannon with a scope?

Not criticizing, just curious...

SR has always been a little loose with their use of the term "cannon", especially in earlier editions. This has always annoyed me (see my previous thread on the topic linked to above). Anyway, in 4th Ed. they have done away with the Victory and Vengeance (at least for now). Arsenal only includes the Vigorous (which is clearly a man portable assault cannon AKA anti-material rifle) and the Vigilant and Vanquisher autocannons (which are clearly described as large caliber miniguns). The large bore cannon have been replaced by the SA GM Light Cannon and the SS GM Heavy Cannon, which I envision to be similar to the weapon systems you mentioned above.

P.S.- Awesome size comparison photos! Thanks for posting!

The russians had a 14.5 mm that they used in WWII as an antitank rifle (the RTRS-41). It was also the caliber of one of their hevier machine guns (KPV). Though they did have 12.7mm called the DShk.

For a sniper rifle, a .50 cal with AV ammo is pretty much all you should need to take out a limo's engine block(the Barret with AV rounds has a total of -10 to armor). However, that also depends on how heavily armored the limo is.

Wouldn't that nifty Gauss cannon thing in arsenal be what you are looking for?

Because it would have a better barrel, an action job, and a far superior scope if it was designed as a sniper weapon. Don't forget that 2000m+ shots are fairly common with modern .50 BMG sniper rifles so the wussy-ass 1500m range in the BBB for sniper weapons is rather inadequate considering how these weapons would only get better by 2070.

So add an 'Extreme' range that is 1.5x long range. Require magnification, half the dice-pool before any situational modifiers, and reduce the base damage and AP down a point or two.

This would ensure that the Sniper has to take an action or two making perception test (gotta find the target at this insane range), at least one Aim action (to get the Magnification effect), and with the reduced dicepool it would mostly only be effective against unaware targets or ones stupidly remaining stationary and exposed to the sniper. Kinda like real life that...

*Edit*
Also, large bore sniper rifles are not the best for extremely long range. In fact, the .50 BMG is a poor long range sniper round design. Know why the military uses it? They got a bizillion of that round.

You want to see a good example of a quality long range sniper round? The Barrett .416 is your answer. Not near as much raw muzzle energy as the BMG round, but it holds onto it a whole lot better, has a flatter flight, and stays hyper-sonic to past 2000m. The round itself was specificly developed for extremely long range shooting and will outperfrom any of the high powered rounds on the market, especially all those with a larger bore (Not counting auto-cannon rounds here ok, but those are not good sniping rounds anyway).

Nah at these ranges we would be using a tac-net of flying drones with the gunnery program, and a computer assisted motorised tracking.

This would not be one person behind the rifle, but optical cable to a commlink/rerouter so that the person could be cheering in the crowd with a laser designator hidden as a camera as the limo passes by.

I think I don't believe in "too much."

I don't think that the Geneva Conventions forbid ammunitions based on the caliber, only the type; the reason is mostly that the rifle and ammunitions are expensive and too bulky to be used against infantry (they can be used and are extremely effective, a Barret won't give a frag about armor, but most of time the same result can be obtained with much lighter and easier to handle sniper rifles).

Incidentaly Barret is developing an antimaterial rifle that fires 25x59 mm ammunitions.

Rule 37: There is no 'overkill.' There is only 'open fire' and 'time to reload.'

Just for the record, it was the Hague Accord, not the Geneva Convention...

The 20mm anti-tank rifle has been around forever. See, as examples, the Japanese Type 97, the Finish Lahti L-39, and the Solothurn S-18/100.

They weren't popular for a variety of reasons: weight and size mean that they are not really man portable (~2meters, 50 kg). In addition, they had a bad habit of breaking collar bones, due to their huge recoil. Plus they were generally only effective against early war tanks.

The 25mm 'Payload Rifle' that you see people trotting out occasionally is much closer to a high velocity grenade launcher. The 25mm rounds achieve effect vs armor via Munroe effect explosive charges rather than kinetic energy. This also allows it to retain its full anti-armor/anti-material effect at range. The rifles that rely on KE to penetrate armor have trouble with penetration at range.

I think its safe to assume that this technology is already built into the SR assault cannon rounds, at least as described in 4th ed.

Always reminds me of Unintended Consequences...

I also wanted to mention that I find the timing of this thread impeccable. Just a few weeks ago I was thinking about how I still needed to make the Panther Cannon Sniper that I have been contemplating, and this thread has provided further inspiration.

Hooray for Dumpshock!!!

Correction: it is not against the rules to shoot someone with a .50 sniper rifle. *rolls his eyes* So much for listening to one's friends. Apparently it's one of those uber pervasive, ongoing urban legends.

Heh, I could have told you that. We gotta get a full briefing on those rules every time we deploy to a combat zone. Nothing wrong with shooting people with a 50. Actually nothing wrong with shooting them with a bushmaster (27mm) or even 155mm guns.

I actually don't even bother trying to correct people anymore because they tell me (a soldier, who has to live by those rules) that I'm wrong and "bla-bla-bla shot someone with a 50 and you go to jail bla-bla-bla".

technically according the Hague Accords its illegal to bomb targets from the air. Shows you how relevant those conventions are now-a-days...

[edit]Sorry. To be specific thats saturation bombing...

My dad told me that when he was in Vietnam he used to use a duce with a scope rigged for night vision on one of the fixed defensive positions on the arty hill he was guarding at the time.

Related, but not directly: whatever happened to Austere Emancipator? He was always great for input on this kind of topic.

That's a good question. He really was a wealth of knowledge.

There are a lot of familiar faces that I miss... I think it was the Forum's transition to primarily supporting SR4 that likely alienated some of them.

Personally, I much preferred the separate SR3 and SR4 Forums. I've often wondered if having an SR3 sub-forum would bring back some of the old-timers...

We have:

Raygun; might still be around, but says very little these days.

HullBreach; last seen 26th April 2008

Austere Emancipator; last seen 13th May 2007

FrostyNSO; RIP ~June 2006