Challenger II is underpowered

[Guest Killjoy]

Sorry for the OT noobish question,but what is the advantages/disadvantages of a smoothbore Vs rifled barrel?

I was under the impression that rifled was better as it "spun" the round making it more stable in flight.

Is this now not needed,so employ smoothbore barrel,if so why?

Cheers,

Mick.

I suppose you could ask the same question like; "Would you rather have the ability to punch someone hard enough to knock them out cold, but be likely to miss, or the ability to punch someone, hit them exactly where you were aiming, but have slightly decreased energy behind it?".

[DarkLabor]

Yes but HESH has the same "terminal effect" on any solid surface, not just armour.

Yes, I tend to be focused on the armor defeating role when I have to explain the principle of HESH rounds.

So it will do the same thing to concrete with a similar adverse effect on the occupants of say a concrete or masonry bunker or other hardened structure.

It all depends on thicknesses and quality of the concrete material.

If the concrete wall is too thin or made of a poor quality concrete, it will act like HE.

DL, I imagine any composite armour- ceramics, plastics, rubber spacers, etc- are likely going to interfere with this shockwave? It seems to me that HESH is going to struggle against the composite-armoured portions of, say, a T-72B?

Right.

Any significant variation of density within a volume is so much interfaces that will reduce the effect of the shockwave that is supposed to produce the spall.

[Kyle Harmse]

I suppose you could ask the same question like; "Would you rather have the ability to punch someone hard enough to knock them out cold, but be likely to miss, or the ability to punch someone, hit them exactly where you were aiming, but have slightly decreased energy behind it?".

Fin-stabilised APFSDS and the new DM-11 fired out of L44 smoothbores are pretty accurate Killjoy :-P

Considering that their stabilisation is independent of the barrel, just like British APFSDS rounds are.

[Hedgehog]

Hmm, I wonder if storing Charm Rounds cross wise might lead to the ability for a Penetrator length increase?

[Gibsonm]

Fin-stabilised APFSDS

So "FSAPFSDS"?

I think one of the "FS" there is redundant.

[Kyle Harmse]

So "FSAPFSDS"?

I think one of the "FS" there is redundant.

Hehe, you got me, though I was trying to say that there's a whole family of fin stabilised rounds now including kinetic energy long rods, HE and HEAT. Tech has marched on, and its just strange to hear rifling still being touted as an accuracy enhancing feature on tank guns, HESH and older rounds notwithstanding.

[Ssnake]

Why do they love the HESH round so much anyway?

I don't claim to know the motives behind the original decision - whether it was irrational love or something else. That said, one fella I met a few years ago pointed out that the UK at the time had a huge stockpile of 120mm war ammo for a rifled gun (from the 1960s Conqueror heavy tank) and that the decision to continue using the rifled design was motivated by the desire not to spend a godawful amount of money to replace the HESH stocks with HEAT rounds (which were rightfully considered as inferior in the general HE/fragmentation role) or a newly to be developed dedicated HE/fragmentation round (like the 120mm DM11, introduced barely three and a half decades after the 120mm smoothbore round was adopted by the rest of NATO).

At the time, when the Challenger 1 was introduced, it wasn't a clear-cut case which gun design would be superior. The Brits probably hoped that the 120mm gun would be adopted by most 105mm L7 gun users, and in any case ammunition production was done at a higher rate by the domestic Royal Ordnance factories, so there probably wasn't the prospect of drying up R&D funds.

As it turned out however a lot of money was poured into smoothbore gun ammo R&D, and the majority of tank gun customers opted for the higher performance of smoothbore-fired APFSDS rounds (IOW, the anti tank role of the tank). In addition, some point out that the British government never put any energy behind marketing the Challenger for export in the various NATO tank trials that were held in the 1980s and 1990s, and the one-time abysmal CAT performance didn't help to build a good reputation either.

So, what might have been rectified by bigger numbers and consequently more R&D investments apparently fell behind.

[Grenny]

Hehe, you got me, though I was trying to say that there's a whole family of fin stabilised rounds now including kinetic energy long rods, HE and HEAT. Tech has marched on, and its just strange to hear rifling still being touted as an accuracy enhancing feature on tank guns, HESH and older rounds notwithstanding.

Fin stabilization is in some cases inferior to spin. Aerodynamics can be a bitch :-P and small deviations can lead to a quiete big spread of rounds.

For example, the DM-11 didn't receive the HEAT-like "stand-off-probe" to produce standoff...

You don't have that fuzz with a spinning round.

[Kyle Harmse]

Fin stabilization is in some cases inferior to spin. Aerodynamics can be a bitch :-P and small deviations can lead to a quiete big spread of rounds.

For example, the DM-11 didn't receive the HEAT-like "stand-off-probe" to produce standoff...

You don't have that fuzz with a spinning round.

Sure, DM-11 is probably unnecessarily complicated compared to a HESH round and as we've said already rifled is superior for full-bore rounds.

It's just that sub mil dispersion for smoothbore guns firing APFSDS is pretty impressive, and pretty good for anti-tank work at 2-3km :-P

*edit* Also illustrates your point of minor variations nicely, and shows how important it is to have a gun/FCS rounds properly "tuned"/zeroed for a round too :-P

I don't claim to know the motives behind the original decision - whether it was irrational love or something else. That said, one fella I met a few years ago pointed out that the UK at the time had a huge stockpile of 120mm war ammo for a rifled gun (from the 1960s Conqueror heavy tank) and that the decision to continue using the rifled design was motivated by the desire not to spend a godawful amount of money to replace the HESH stocks with HEAT rounds (which were rightfully considered as inferior in the general HE/fragmentation role) or a newly to be developed dedicated HE/fragmentation round (like the 120mm DM11, introduced barely three and a half decades after the 120mm smoothbore round was adopted by the rest of NATO).

At the time, when the Challenger 1 was introduced, it wasn't a clear-cut case which gun design would be superior. The Brits probably hoped that the 120mm gun would be adopted by most 105mm L7 gun users, and in any case ammunition production was done at a higher rate by the domestic Royal Ordnance factories, so there probably wasn't the prospect of drying up R&D funds.

As it turned out however a lot of money was poured into smoothbore gun ammo R&D, and the majority of tank gun customers opted for the higher performance of smoothbore-fired APFSDS rounds (IOW, the anti tank role of the tank). In addition, some point out that the British government never put any energy behind marketing the Challenger for export in the various NATO tank trials that were held in the 1980s and 1990s, and the one-time abysmal CAT performance didn't help to build a good reputation either.

So, what might have been rectified by bigger numbers and consequently more R&D investments apparently fell behind.

Interesting insight as always Ssnake. Maybe worth a spot of research one day.

[Grenny]

...of course i was talking full bore rounds. Above a certain l/d ratio...center of mass and center point of stabilization get to far of. Hence for all sabot rounds FS is the only way.