The Best That Never Was 2 (Prototypes)

[swaghauler]

Originally Posted by Vespers War

A mix-and-match firearm this time, the LeMat Carbine. Yes, the carbine, not the revolver. Well, sort of the revolver...it's complicated.

You see, Doctor Colonel Jean Alexandre LeMat wanted to produce long arms in addition to his 9-shot revolvers with shotgun goodness in the center. So he produced 9-shot revolving carbines with either shotgun or rifle goodness in the center. Around 200 of these were made, and the handful of survivors vary in caliber for both the central barrel and the surrounding revolver. All have 20" barrels and I estimate the weight at 4.5 kilograms (seriously, if anyone can find an actual weight, I'd appreciate it, because Google is failing me on that point of research).

Revolver options:
Original (10.668x47mmBP Conical)
Dam 2, Pen Nil, Ammo 9i, ROF SAR, Bulk 6, SS 1, Rng 74
Pinfire (11mm French Ordnance)
Dam 2, Pen Nil, Ammo 9R, ROF SAR, Bulk 6, SS 1, Rng 59

Center options:
.56 rifled (14.224x31mmBP Conical)
Dam 3, Pen Nil, Ammo 1i, ROF SAR, Bulk 6, SS 3, Rng 98
.58 rifled (14.732x31mmBP Conical)
Dam 3, Pen Nil, Ammo 1i, ROF SAR, Bulk 6, SS 3, Rng 102
20 gauge shotgun
Dam 9 (close)/1x11 (medium), Pen Nil, Ammo 1i, ROF SAR, Bulk 6, SS 1, Rng 12

The powder charge is probably a little high for the original revolver load (it's roughly 63 grains), but I was trying to maximize range. The .56 rifled is a 74 grain load and .58 rifled is a 79 grain load. Again, they were calculated to maximize range using FF&S.

The 9i for reload on the first option is because it's a lead bullet loaded over loose powder, so it's slower to reload than the self-contained pinfire cartridges. The shotgun range I'm not 100% sure on, because I'm terrible at using FF&S to generate shotgun stats. For the shotgun beyond close range, treat it as a 5-round burst and two 3-round bursts.

While the carbine was apparently made into the centerfire era, I haven't seen any records of what calibers were manufactured, and I'm not sure any of them are among the 18 known survivors.

I know you do good work... but these formulas in FF&S and WTG are STILL driving me crazy. Here are weapons with a fairly low sectional density and TERRIBLE Ballistic Coefficient being driven by [low velocity] BLACK POWDER to boot. Yet when I even run the formulas you get SHORT RANGES around a hundred meters in a game where high-velocity smokeless powder loads with excellent Ballistic Coefficients are hitting 75m to 80m max. The Range formula seems off by at least 1/3 too much. I noticed this in your entries on the Primitive Weapons Thread too. I think the Forum needs to brainstorm the modification of those formulas.

[ChalkLine]

On my quest to make the perfect Twilight 2000 Sheridan I think I've finally found it.

Believe it or not but way back in 1967 there was already concerns that the M81 (as it was then) Gun/Launcher may not be a good idea. As such Rock Island Arsenal did a crash program of four other weapon systems to fit in the M551 turret should the M81 develop problems.

Of the four only two were recommended mainly due to space problems, although it was mentioned that if serious redesign work was done all four would fit in the turret. The two weapon systems were:

- M32 76mm Cannon, the same as was on the M41 Walker Bulldog
- XM180 105mm Gun/Howitzer from the XM104 super mobile lightweight howitzer (which really should have gone into service)

Of the two the XM180 was the preferred weapon system as it coupled low pressure and trunnion loading with high damage output and ammunition that was still largely in service.
This weapon fired much faster than the existing M81 because it didn't need a compressed air purge to blow out the bore so the combustible cartridge cases wouldn't ignite prematurely. It's likely that by the time of the Twilight War an A1 version of the gun/howitzer would have been developed with a bore evacuator for even faster firing. Notably the XM108 could fire any 105mm howitzer ammunition in US stocks and new racks for the vehicle gave a stowage of 50 Rounds. (I note the UK ammo has a squash head round)

If the M551A1 is the M81-armed standard version with vision upgrades and a minor modernisation package that would make the M32 76mm the M551A2A1 and the XM108 105mm the M551A3A1

Here's an image of the gun way back in 1967

[Raellus]

That's an interesting concept, Chalk. The XM180 would make a great light assault gun for MOUT*, but it kind of loses the Sheridan's raison d'etre as an AT-capable light tank for Airborne forces.

Was there ever an AT round developed for 105mm howitzers? Something that could be used when the SHTF?

*And with "Beehive" rounds, it would be deadly against infantry in the open.

[micromachine]

Seem to recall the M101 howitzer having a HEAT round. While not a sabot round, it can have a decent punch if used in the correct way.

[ChalkLine]

Originally Posted by Raellus

That's an interesting concept, Chalk. The XM180 would make a great light assault gun for MOUT*, but it kind of loses the Sheridan's raison d'etre as an AT-capable light tank for Airborne forces.

Was there ever an AT round developed for 105mm howitzers? Something that could be used when the SHTF?

*And with "Beehive" rounds, it would be deadly against infantry in the open.

Originally Posted by micromachine

Seem to recall the M101 howitzer having a HEAT round. While not a sabot round, it can have a decent punch if used in the correct way.

(A lot of this is cut-and-pasted from the FB page)

Importantly this whole process was reversible. You could swap guns and racks in a few hours.

The way I see this thing going down is that the ammo for the M81E1 is going to get used up and they simply don't make it anymore. At that point these weapons and racks are shipped out to divisional workshops and the systems swapped over. M81E1s in still good condition are shipped back up the chain to where the few remaining M551 units are that are near supply chains that have the ammo as spares.
Yes, it does lose tank-killing ability but hey, TOWs are everywhere. If the crew really want to go tank hunting they can keep a MILAN in the bustle rack

Otherwise they have two jobs; the first is skirmishing with other recon assets. Now the flyboys and the satellites are gone it's back to going-out-and-having-a-look. This means you'll be meeting PT-76s (which, as I posted earlier on a long micro-essay, isn't actually a scout vehicle but something entirely else), BRDMs and the odd BMP.
The second is infantry support. Unlike IFVs the big honking gun can drop entire buildings and break open bunkers. They were actually used like this in Panama.

The "beehive" rounds were the famous APERS-T. It was used extensively in Vietnam in anything that used a low recoil barrel.
It's been replaced with a special airbust setting on the various fuzes that lets you use standard shells, this is the mechanical time–super quick (MTSQ) fuze. With this you can set the shell to blast nearby targets but it also gets those in trenches, crawling or otherwise in cover.
Who'd be an infantryman?
I'd still put one or two APERS-Ts in the rack if I had a chance for targets of opportunity.

Elsewhere we've done some discussion on what the range and rate of fire would be.
Now, obviously the default information for this would be Paul's standard NATO 105mm howitzer. However I don't know which gun Paul based this on, and if it was a semi-automatic breech as is on the XM180 mentioned or the manual interrupted screw on the M103 105 mm Howitzer off the M108 (they tried to fit this originally and it would have meant moving traverse gear, something they didn't want to do). Also howitzer fire rates are based on "sustained fire" shooting, whereas direct fire rates are usually much higher as you're essentially in a shit-has-hit-the-fan situation. I'm not sure what if the direct fire range listed in Paul's rules are the same as something with a dinky little barrel like the XM180. I'll leave that answer for the specialist cannon-cockers here.

[Vespers War]

Originally Posted by ChalkLine

On my quest to make the perfect Twilight 2000 Sheridan I think I've finally found it.

Believe it or not but way back in 1967 there was already concerns that the M81 (as it was then) Gun/Launcher may not be a good idea. As such Rock Island Arsenal did a crash program of four other weapon systems to fit in the M551 turret should the M81 develop problems.

Of the four only two were recommended mainly due to space problems, although it was mentioned that if serious redesign work was done all four would fit in the turret. The two weapon systems were:

- M32 76mm Cannon, the same as was on the M41 Walker Bulldog
- XM180 105mm Gun/Howitzer from the XM104 super mobile lightweight howitzer (which really should have gone into service)

Of the two the XM180 was the preferred weapon system as it coupled low pressure and trunnion loading with high damage output and ammunition that was still largely in service.
This weapon fired much faster than the existing M81 because it didn't need a compressed air purge to blow out the bore so the combustible cartridge cases wouldn't ignite prematurely. It's likely that by the time of the Twilight War an A1 version of the gun/howitzer would have been developed with a bore evacuator for even faster firing. Notably the XM108 could fire any 105mm howitzer ammunition in US stocks and new racks for the vehicle gave a stowage of 50 Rounds. (I note the UK ammo has a squash head round)

If the M551A1 is the M81-armed standard version with vision upgrades and a minor modernisation package that would make the M32 76mm the M551A2A1 and the XM108 105mm the M551A3A1

I believe there were only three different weapons tested. Two of the four were the M32 76mm, one with the M76 recoil system (from the M41) and the other using an adapted M81E12 recoil system (from the M551).

Assuming the XM180 uses the same ammunition as the M101 howitzer, the M327 HESH/HEP round would be available, with an 80% chance of spalling 5 inches of armor at 60 degrees obliquity. If any M67 HEAT was still around, it would also be usable, but IIRC it was replaced by the M327 pretty quickly in the late 50s.

[StainlessSteelCynic]

Another benefit of Beehive rounds is that because they don't use HE, they are often quite effective for creating entry points into buildings or through walls (without the risk of explosive throwing its blast or debris back onto the vehicle or accompanying troops).

[ChalkLine]

Originally Posted by Vespers War

I believe there were only three different weapons tested. Two of the four were the M32 76mm, one with the M76 recoil system (from the M41) and the other using an adapted M81E12 recoil system (from the M551).

Assuming the XM180 uses the same ammunition as the M101 howitzer, the M327 HESH/HEP round would be available, with an 80% chance of spalling 5 inches of armor at 60 degrees obliquity. If any M67 HEAT was still around, it would also be usable, but IIRC it was replaced by the M327 pretty quickly in the late 50s.

Yeah, the 76mm was tested twice; once with it's own recoil system and once with the M81 recoil system.

[Vespers War]

I've recalculated the numbers for the LeMat using best guesstimates of powder charges. The decimal measurements are caliber and grains of powder (i.e. .42-16 is a .42" ball and 16 grains of powder). The shotgun has two statlines for ball and for shot.

The 60 grain load for the .56 is the midpoint of what was used in Civil War carbines (Merrill's used 50 grains, Colt's 60 grains, and Burnside's 75 grains), while the 75 grain load for the .58 matches the rifle-musket. Barrel lengths are 19.687" (50cm) for the revolver and 17.375" (44.1325cm) for the center.

Pinfire and centerfire carbines would tend to have the shotgun barrel, while the muzzle-loader might have any of the center barrels. The 9R calibers will still be slow to load, since they require single ejection of spent cases with a non-spring-loaded punch and single loading of new rounds through a gate.

LeMat Carbine
Revolver loads
.42-16 (10.668x12mmBP Ball)
Dam 1, Pen Nil, Ammo 9i, ROF SAR, Bulk 6, SS 1, Rng 35
12mm Perrin Pinfire (12x15mmR BP Conical)
Dam 2, Pen Nil, Ammo 9R, ROF SAR, Bulk 6, SS 1, Range 62
11mm French Ordnance Centerfire (11.47x17mm BP Conical)
Dam 2, Pen Nil, Ammo 9R, ROF SAR, Bulk 6, SS 1, Range 63

Center barrel loads
.56-60 Rifled (14.224x25.2mmBP Conical)
Dam 2, Pen Nil, Ammo 1i, ROF SAR, Bulk 6, SS 2, Rng 87
.58-75 Rifled (14.732x29.35mmBP Conical)
Dam 3, Pen Nil, Ammo 1i, ROF SAR, Bulk 6, SS 2, Rng 81
20-gauge slug (15.75x13.7mmBP Ball)
Dam 2, Pen Nil, Ammo 1i, ROF SAR, Bulk 6, SS 1, Rng 23
20-gauge shot
Dam 11 (close)/1x15 (medium), Pen Nil, Ammo 1i, ROF SAR, Bulk 6, SS 1, Rng 12

[Vespers War]

Originally Posted by swaghauler

I know you do good work... but these formulas in FF&S and WTG are STILL driving me crazy. Here are weapons with a fairly low sectional density and TERRIBLE Ballistic Coefficient being driven by [low velocity] BLACK POWDER to boot. Yet when I even run the formulas you get SHORT RANGES around a hundred meters in a game where high-velocity smokeless powder loads with excellent Ballistic Coefficients are hitting 75m to 80m max. The Range formula seems off by at least 1/3 too much. I noticed this in your entries on the Primitive Weapons Thread too. I think the Forum needs to brainstorm the modification of those formulas.

I think the problem is with smokeless more than BP. The Springfield Model 1855 rifle-musket was noted to be effective to 500 meters and deadly to 1 kilometer, firing 14.7x23.5mm BP Conical (.58 with 60 grains of powder) from a 101.6 cm barrel. Arguably the range should be around 125 so that it has 125/250/500/1000 as its range bands, using long as effective range and extreme as the range at which it can (with major luck) inflict casualties. Actual calculated range is 89, which is 28.8% low. I know from tests a while back that the formulas really have problems with the Whitworth, which hit targets at 1.8 kilometers in trials.

The GDW rules also don't have a good way to simulate the trajectory problems of black powder that required better range estimation than with high-velocity small-caliber smokeless powder. Black powder rifles had plenty of accurate range, but they needed accurate range estimation to be of any use, and that's something that could probably use a house rule.

I think the problem for the LeMat specifically is that I went for the powder charge that maximized range, which is almost certainly heavier than what was used, since the .58 BP exceeds the service charge for the rifle-musket. I don't know what charges were actually used, and lighter charges would reduce range.

[swaghauler]

Originally Posted by Vespers War

I think the problem is with smokeless more than BP. The Springfield Model 1855 rifle-musket was noted to be effective to 500 meters and deadly to 1 kilometer, firing 14.7x23.5mm BP Conical (.58 with 60 grains of powder) from a 101.6 cm barrel. Arguably the range should be around 125 so that it has 125/250/500/1000 as its range bands, using long as effective range and extreme as the range at which it can (with major luck) inflict casualties. Actual calculated range is 89, which is 28.8% low. I know from tests a while back that the formulas really have problems with the Whitworth, which hit targets at 1.8 kilometers in trials.

The GDW rules also don't have a good way to simulate the trajectory problems of black powder that required better range estimation than with high-velocity small-caliber smokeless powder. Black powder rifles had plenty of accurate range, but they needed accurate range estimation to be of any use, and that's something that could probably use a house rule.

I think the problem for the LeMat specifically is that I went for the powder charge that maximized range, which is almost certainly heavier than what was used, since the .58 BP exceeds the service charge for the rifle-musket. I don't know what charges were actually used, and lighter charges would reduce range.

GDW went with what is termed "practical accuracy" which is what the average shooter could pull off "in the field." What you are modeling would be called "mechanical accuracy" or "benchrested accuracy" for expert shooter or shooters using controlled conditions. My issue with changing the four range band model of RAW is that you will break the practical accuracy of both pistols and SMGs if you change the formula to properly address the maximum "mechanical" or benchrested range of rifles using the four range bands.

I agree with you that GDW needed to take into account the effective long-ranged accuracy but I think they just needed to add one more Range Band. The Maximum Effective Range band. This would allow those spectacular shots that are legendary today. I also agree with optics, bipods, and tripods adding to the Base Range. I just think they didn't go far enough with scopes. Why do I add another Range Band? Just look at what happens with the M16A2

Short Range = 55m, Snap Shot: Average (Skill), Aimed Shot: Easy (Skillx2)
Medium Range = 110m, Snap Shot: Difficult (1/2Skill), Aimed Shot: Average
Long Range = 220m, Snap Shot: Formidible (1/4Skill), Aimed Shot: Difficult
Extreme Range = 440m, Snap Shot: Impossible (1/10Skill), Aimed Shot: Formidable

And finally my Maximum Effective Range...
Maximum Effective Range = 880m, Snap Shot: NO, Aimed Shot: Impossible

This allows that impressive one in a million shooter WITHOUT compromising the fairly accurate practical accuracy in the RAW game. It also allows for the positive effects of things like optics and bipods with an easy to apply mechanical advantage by simply adding range.

[Legbreaker]

Originally Posted by swaghauler

I agree with you that GDW needed to take into account the effective long-ranged accuracy but I think they just needed to add one more Range Band. The Maximum Effective Range band. This would allow those spectacular shots that are legendary today.

I LIKE it!
I'd be inclined to consider a max possible range also much like GURPS and their 1/2 Damage stat - anything beyond that has penalties to both accuracy and damage.
Knowing the max possible range allows for using tripod mounted machineguns in the indirect roll, something which has been done for well over a hundred years for suppressive fire and in some circles known as the poor mans artillery (unless you're the one paying the ammo bill!).

[StainlessSteelCynic]

I like it too.
My gaming group has always had a bit of a liking for the idea of adding items to gear to improve them e.g. putting better tyres on a vehicle, putting a better scope on a rifle and so on. Basically a way to let a Character improve their chances with a Skill check, especially if they are not particularly good in that Skill.

If I can con my group into any game using the 2.2 rules, I'm very much inclined to use your idea Swaghauler

[swaghauler]

Originally Posted by Legbreaker

I LIKE it!
I'd be inclined to consider a max possible range also much like GURPS and their 1/2 Damage stat - anything beyond that has penalties to both accuracy and damage.
Knowing the max possible range allows for using tripod mounted machineguns in the indirect roll, something which has been done for well over a hundred years for suppressive fire and in some circles known as the poor mans artillery (unless you're the one paying the ammo bill!).

I used to give a bonus of 1 to a roll for any tripod that had Traverse and Elevation gear on it. Now I'll probably give a BOON (The Mongoose Traveller version of ADVANTAGE) because it does make a big difference in accurate fire from a tripod.

[StainlessSteelCynic]

It's an interesting idea. I like the advantage/disadvantage idea for certain circumstances but I'm not sure I like it for equipment that gives you a mechanical advantage e.g. the tripod.
The ad/disad system generally gives you an equal chance of scoring good or bad so I figure this means that if you get two lousy results for the skill check the tripod hasn't really done anything extra for you when it should.
However if it adds to your skill check in some way then the percentage chance of success is somewhat better all the time making it worthwhile to use whenever you can.
Players want to stack the odds in their favour, it's natural, they want their characters to survive & thrive. The ad/disad system feels like it completely negates the ability to shift the odds a little more in your favour when using something like the tripod in this example.

[swaghauler]

Originally Posted by StainlessSteelCynic

It's an interesting idea. I like the advantage/disadvantage idea for certain circumstances but I'm not sure I like it for equipment that gives you a mechanical advantage e.g. the tripod.
The ad/disad system generally gives you an equal chance of scoring good or bad so I figure this means that if you get two lousy results for the skill check the tripod hasn't really done anything extra for you when it should.
However if it adds to your skill check in some way then the percentage chance of success is somewhat better all the time making it worthwhile to use whenever you can.
Players want to stack the odds in their favour, it's natural, they want their characters to survive & thrive. The ad/disad system feels like it completely negates the ability to shift the odds a little more in your favour when using something like the tripod in this example.

One of the options I have been considering is a Skill Level based bonus. My players are REALLY ENJOYING my [RAW] skill-based rules for Outstanding and Exceptional Success*, so I have been considering:

Skill Level 0 = No bonus as you are not knowledgable enough to gain a bonus.
Skill Level 1 thru 6 = A bonus of 1 to the roll for tripods with T&E gear.
Skill Level 7 thru 9 = A bonus of 2 to the roll for tripods with T&E gear.
Skill Level 10 = A bonus of 3 to the roll for tripods with T&E gear.

This will give more skilled gunners a better bonus (as befits their higher experience).

* My Skill Level based bonus is designed to reward high Skill Levels (training) over high Characteristics (natural talent) and it works like this. You get an Outstanding Success if you roll under your RAW base Skill Level on an AVERAGE Task. To get an Exceptional Success, you must roll under HALF of your RAW Skill Level on 1D20. So, in practice, it looks like this:

A PC with an Attribute score of 7 and a Skill Level of 3 would succeed at an AVERAGE task on a roll of 10 or less. They would score an Outstanding Success IF they rolled a 3 or less. They would score an Exceptional Success on a roll of 1.

A PC with an Attribute score of 3 and a Skill Level of 7 would also succeed on a roll of 10. HOWEVER, they would achieve an Outstanding Success on a roll of 7 or less. They would achieve an Exceptional Success on a roll of 3 or less on an AVERAGE Task.

On an Outstanding or Exceptional Success, you score a Special Manuever. My players have a great affinity for this new system and I have LOTS of positive feedback on Skill-based Success.