If the vehicle is enough protected against a 30x113 HEDP, then it is enough valuable. And if it is enough valuable, it will be really more expensive than any ATGM or other future AT system like a loiter UAS.

I just don't understand why in 2021 AP capabilities of auto cannon is taken seriously anymore, given the myriad of AT options. I rather would think that payload capabilities, either cUAS, AP or in general urban fighting is more important by far.

And any 20mm lacks payload capability for using airburst ammunition and thus being a meaningful cUAS / antipersonnel in defilade system

poliorcetes said:

I just don't understand why in 2021 AP capabilities of auto cannon is taken seriously anymore, given the myriad of AT options. I rather would think that payload capabilities, either cUAS, AP or in general urban fighting is more important by far.

Autocannon AP ability may return to relevance if there is a proliferation of Active Protection Systems (APS) that make ATGMs unreliable. As far as we know APS doesn't work on screamingly fast APDS/APFDS. I could see that as part of the rationale for the 30x173mm Stryker, as well as the bigger AC's like the 40 CTA and 50-57mm developments the US and Russia are looking into.

But the sorts of vehicles that have APS that could defeat Javelins and other sophisticated ATGMS...more then likely armored well against Autocannons as well. At the least, almost certainly armored agains 'low end' AC's like 20x102. 

Overall as you said, for most realistic / useful light cannon applications (anti infantry, anti drone, anti structure, anti material) the 30mm is really the answer. Maximum HE, moderate recoil, with room for growth in both improving Frag as well as possibly improving the HEDP penetration through a more advanced little copper cone. 

In terms of .50's on RWS, is there any merit in switching from the M2 browning to the M3P version, which has 2x the ROF (1100rpm)?

To me this would seem a nice upgrade for the RWS, as it would allow a burst to put roughly 2x the amount of rounds on target in the amount of time as the M2, and the RWS would handle the recoil to ensure accuracy. 

That would seem to improve the chances of hitting moving infantry/vehicles, or having enough rounds hit an armored vehicle that one may disable an important sensor. All while keeping the same basic .50 setup and most of the same logistics.

YouTube

Browning Fn M3M calibro .50

La prova a fuoco della mitragliatrice Fn M3M calibro .50, erede della leggendaria M2.

Whats the approximate core diameter of bog-standard .50 AP? (not SLAP) 

gatnerd said:

In terms of .50's on RWS, is there any merit in switching from the M2 browning to the M3P version, which has 2x the ROF (1100rpm)?

To me this would seem a nice upgrade for the RWS, as it would allow a burst to put roughly 2x the amount of rounds on target in the amount of time as the M2... 

That would seem to improve the chances of hitting moving infantry/vehicles... All while keeping the same basic .50 setup and most of the same logistics.

It sounds good in theory, but how much difference does it make in reality?

     M3 - https://youtu.be/gBcvKTYUFq8?t=19

     M2 - https://youtu.be/MWrthRBdhTA?t=1

Switching from the M2 to the M3 would have some significant drawbacks:

1.  It would consume ammo 2X as fast.

2.  It would burn up barrels 10X as fast.

3.  It would require buying a whole bunch of new manufactured M3 guns.

While FN would love the idea, I dunno if the gain would be worth the cost.

My understanding is that they are tired of having to retightening the bolts on the chopper after using the 30mm cannon. Less maintenance time.

Farmplinker said:

My understanding is that they are tired of having to retightening the bolts on the chopper after using the 30mm cannon. Less maintenance time.

That would be pretty weird, you'd imagine they'd have figured out some sort of Locktite like solution there in the last 40 years?

The Eurocopter Tiger uses a 30x113 GIAT, while Russia's MI28 and KA-52 use the even more beastly 30x165mm. I'd think at this point the 'copter mounted 30mm would be a non issue. 

Werent they considering the caseless Rmk30 for the tiger..

Can choppers use APDS or is it still too risky

smg762 said:

Can choppers use APDS or is it still too risky

The AH-1's M197 is cleared to fire MK149 (Phalanx) APDS ammo. I presume that the reasons are connected with the low mounting of the gun compared to the engine intakes, and the fact that the downwash from the rotor will push the sabot pieces even further away.

Maybe there is more of a push for USMC AH-1 to be able to use the same ammo as the Phalanx system since USMC helos would spend a lot of time riding on USN amphibs.