Does anyone have more info on the Mauser experimental 27x143b. I grabbed a couple of images off of CSA’s auction page. Here’s his description of it.

27x145b reformed/loaded to an OAL that would fit in the 20x139 HS820 cannon with 27mm barrel.


CSA auction = ???

It is not a reformed 27x145B. Cartridge OAL does not match the 20x139 and also not the OAL of a 30x113B.
The case head is from a 30x113B. So no relation to a 20x139 system at all.
Cases weere made by Manurhin for Mauser/IWK. The projectile has a plastic driving band.
These were made for Aerojet in the US and delivered in inert state to be loaded in the US. Only 150 ever made and never used as the project was cancelled. Woodinlab got the inert cartridges and also never found out what the project was about.
Almost all info in that auction is incorrect.

CSAEOD gunbroker auctions.

I located a guy who has some of the projectiles stuffed into 27x145b brass, he thinks they were for an F14 Tomcat gun project.

I doubt…

Segue, was there any competition for the gun in the JSF/F35?

The F-35 evaluation was about the 27x145B BK27 but as we see they ended up with 25x137.

The one above in 27x143B was a project in 1971.

Ok, so I believe the projectil in the middle is the 27x143b experimental, but missing the driving band. Any idea what the other 4 are?

1 Like

So is the one posted originally a real experimental projectile shoved in a different case or is the cartridge correct, with the wrong information attached?

The cartridge is legit, just all wrong info.

Good to know! Thanks!

I’d like to know where I can get a empty 27mm case.

Tom, at every German ECRA show.

Here a comparison image provided by Rolf Pfennig.

Cartridge OAL of the ones in question is clearly way off what was stated in that auction.

Items in the image are:
20x139 (for comparison)
27x143B for Aerojet (the one in question)
27x143B DEFA head (the early 27x145B before it got it’s final head, NOT related to the #2)
27x145B (case)
27x145B (today’s standard)
30x113B (for comparison, a French made one)


sorry for the off topic but it nice to see a french 30x113 with BRASS case ,i know 30x96 (30-540) with brass case but not the 30-550 (30x113)

Indeed it is a scarce one! But no surprise as Rolf’s collection was one of the best European medium caliber collections in it’s days.

Thank you very much for the comparison images!

So it seems the projectile is supposed to be seated that far down in the case? I assume the drive band is then hidden completely inside as well?


In Rolf’s photo, that (3rd from left) Mauser logo on the 27x145B is that factory installed logo sticker? Is it a display dummy?

Very cool!

This should be a factory item.