Slugs and frags

Awang se

New Member
Verified Defense Pro
I read an article once about a possible CIWS system. One is using Super high fire rate 20/30mm auto guns with solid projectiles. The other is slower firing rate large calibre with fragmentation round. I see the first is widely use. the second, except for a ship guns, i'm yet to see it. Anyone know why?
 

tatra

New Member
Verified Defense Pro
What do you mean "not widely used"?:
35 mm Oerlikon and SA-derivatives (AHEAD munition)
40 mm Oto Fast Forty single and twin gun mounts, Bofors
57 mm Bofors
76 mm Oto Super Rapid mount

They are common gun systems (with exemption of 57mm bofors, all available in both land- and shipbased applications) that use fragmentation rounds in CIWS (i.e. anti-missile) role. My guess is that with the smaller caliber guns, a fragmentation round doesn't do enough damage. Hence AP(FSDS)-rounds fired at a very high rate.
 

Awang se

New Member
Verified Defense Pro
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tatra said:
What do you mean "not widely used"?:
35 mm Oerlikon and SA-derivatives (AHEAD munition)
40 mm Oto Fast Forty single and twin gun mounts, Bofors
57 mm Bofors
76 mm Oto Super Rapid mount

They are common gun systems (with exemption of 57mm bofors, all available in both land- and shipbased applications) that use fragmentation rounds in CIWS (i.e. anti-missile) role. My guess is that with the smaller caliber guns, a fragmentation round doesn't do enough damage. Hence AP(FSDS)-rounds fired at a very high rate.
I see, how good is this frag round compare to the solid one. is it effective against supersonic anti-ship missile
 

gf0012-aust

Grumpy Old Man
Staff member
Verified Defense Pro
Awang se said:
tatra said:
What do you mean "not widely used"?:
35 mm Oerlikon and SA-derivatives (AHEAD munition)
40 mm Oto Fast Forty single and twin gun mounts, Bofors
57 mm Bofors
76 mm Oto Super Rapid mount

They are common gun systems (with exemption of 57mm bofors, all available in both land- and shipbased applications) that use fragmentation rounds in CIWS (i.e. anti-missile) role. My guess is that with the smaller caliber guns, a fragmentation round doesn't do enough damage. Hence AP(FSDS)-rounds fired at a very high rate.
I see, how good is this frag round compare to the solid one. is it effective against supersonic anti-ship missile
There were some tests done some years ago by the USN on the Phalanx. From memory they discovered that the 20mm weapon had minimal disruptive effect in a cruise missile until 2-300m. At 2-300m the terminal velocity of the CM was such that even if it was hit, the fragments would still cause considerable damage to superstructure etc...

30mm (Goalkeeper) was more effective but had a lower rate of fire.

Since that test, no new USN vessels have been commissioned with new Phalanx systems. RAM and ESSM were then rapidly developed to take up the CIWS defence layer.

AFAIK 35mm has emerged as the min calibre to effect a cruise missile stoppage. (Hence Contraves/Oerlikon AHEAD)

It's why rapid fire 76mm are still in favour. The 35mm AHEAD system has substantial range - well beyond the 76mm system and it borders on SRAAM distance.
 

tatra

New Member
Verified Defense Pro
Awang se said:
I see, how good is this frag round compare to the solid one. is it effective against supersonic anti-ship missile
As I said, that depend on caliber. In smaller calibers, solid rounds fired at high rates are probably more effective than fragmentation round. At larger calibers, it is more difficult to achieve such high fire rates (e.g. heavier rounds). Fortunately fragmentation rounds of larger caliber are more effective than smaller ones.

The problem with supersonic antiship missiles is not so much that they couldn't be destroyed by gunfire. Rather it is that you have even less time to detect them (spot, classify, pass off to weaponsystem) and react (ready the gun, aim and fire it, then allow for the flight time of rounds) to them then you already have with subsonic SSM.
 
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