I know 40x180 was designed with bushmasters in mind, as an alternative to 30x173,  but with new chambers and barrels is there any reason it wouldn’t work in other cannons designs using 30x173 as far as magazine, feeding etc?

Asking because I’m thinking of a hypothetical GAU-8 rechambering, and if it means not having to replace the whole gun then all the better since it’s so closely integrated into the airframe.

The feed system on the GUA-8 is linkless so it would probably take a major redesign. The shoulder also plays a part in protecting the projectile from being battered in the feed system.  Assuming anyone found a use for the gun it's probably doable but not simple.

https://www.youtube.com/watch?v=33teK7L4DM4&ab_channel=FUNKER530-VeteranCommunity%26CombatFootage

The heavier recoil also requires additional buffering. And there is a question about whether the ammunition, designed to be fired at a low rate (200 rpm), will stand up to the much more violent handling of high-rate guns like the Mauser MK30.

Refleks said...

Asking because I’m thinking of a hypothetical GAU-8 rechambering, and if it means not having to replace the whole gun then all the better since it’s so closely integrated into the airframe.

I’m curious as to what the super 40 would do for you in the GAU-8. I was under the impression that discarding sabot wasn’t an option for aircraft because of the FOD risk, so going to the larger calibre would compromise your velocity over range which would limit AP performance and ease of aiming.

What doesn’t the 30mm do that a 40 would?

Not just discarding sabot parts, the Air Force wouldn't allow the gun system to discard shot cartridge cases (imagine getting hit by a spent GAU-8 case moving at 300 knots). 

A-10  and strafing run on an armored formation is obsolete, A-10 is not survivable for anything but gunning around folks with AKs , flipflops and no real anti-air capability . The battlefield is about to get even deadlier due to need to counter the drones with ever more anti-air guns and missiles than ever before. 

Mr. T (MrT4) said:

A-10  and strafing run on an armored formation is obsolete, A-10 is not survivable for anything but gunning around folks with AKs , flipflops and no real anti-air capability . The battlefield is about to get even deadlier due to need to counter the drones with ever more anti-air guns and missiles than ever before. 

Yup, it was designed as a follow on to the Skyraider with stuck on antitank ability. Something closer to the Su-25 powered by a pair of non afterburning F100s is what they really needed. 

I agree that busting MBTs in the fulda gap by hitting them in the rear with 30x173 is not a mission set that the A-10 is suitable for any longer for a variety of reasons.

I was thinking of a notional 40x180 SAPHE with timed airburst, impact, and delay modes, which along with the greater HE fill, more substantial shell, and PFF would provide significantly improved effects on the target sets they have been engaging over the last 20 years: namely, enemy personnel, softskinned vehicles, light AFVs and robust structures.

The pilot would select the mode (or predetermined mix) from the cockpit based on what he's about to engage, and a fuze setter mounted to the front of the firing barrel would set the mode electronically as it exits the barrel. To provide continuous slant range data for airburst, a small fixed phased array radar would be mounted, perhaps an Osprey 30 derivative.   This would also be able to provide CCIP data for the gun to help offset trajectory tradeoffs over the flatter shooting 30x173.

Since we're not dependent on velocity any longer, if armored vehicles are more of a problem (such as the opening stages of a conflict), a notional 40x180 HEDP (using scaled up 30x113 HEDP internals) using superquick fuzing would provide potentially ~65+mm RHA penetration with secondary HE effects similar to 30mm.

Anyway, I understand the politics behind spending a dime more on the A-10, none of that interests me since this is just a hypothetical I was kicking around in my head anyway. I just didn't know if it would be feasible to redesign the GAU-8 internals to support it, or if other issues (as Tony and others have described) would be a showstopper.

It would certainly be impressive to see.

ZailC said:

Not just discarding sabot parts, the Air Force wouldn't allow the gun system to discard shot cartridge cases (imagine getting hit by a spent GAU-8 case moving at 300 knots).

It also has CG issues if it doesn't keep the shells.

Mr. T (MrT4) said:

A-10  and strafing run on an armored formation is obsolete, A-10 is not survivable

The A-10 conops was obsolete before it was built. That's why they carried triple rail Mavericks, so they could at least attempt BAI & CAS missions before dying in flames.

I cannot recommend this series enough:

http://elementsofpower.blogspot.com/2011/07/debunking-close-air-support-myths-part.html

And this post in particular:

http://elementsofpower.blogspot.com/2011/07/cas-myths-sidebar-a-10-and-cult-of-gun.html