The 1985 Olin SLAP patent, a comprehensible one

The patent filed on 1985 and published in 1989 by Olin Corporation, titled “SABOTED, LIGHT ARMOUR PENETRATOR ROUND WITH IMPROVED POWDER MIX”, is a very interesting document.

It explains the failed Army development of a saboted penetrator projectile for the 7.62 Nato caliber, and how Olin Corp was able to make it work by switching to a very fine grained spheroidal propellant. It is really well written (for a patent) and could make for a post in this specialized forum.

It doesn’t have any drawings, but everybody knows the SLAP round, don’t we? … 1863A&KC=A

For the legal status of the patent, and the patent in other languages, see … 6&tab=main



Though this is an old thread and our dear friend Schneider has left us years ago here the patent with the actual drawings. Maybe of interest to somebody.

Starting on pg 25, In the 2018-3 edition of Very High Power an article on Winchester and the 50 BMG Cartridge by Jim Frigiola notes another factor in making the SLAP design work was a special priming compound.

Pete, interesting! Often seemingly unrelated factors in ammunition development do decide about a whole thing working or not. And I am not neccessarily speaking of real physical and proovable factors here.
I heard such things about a multitude of ammo/gun projects.

Is that article available in digital somewhere?

Hi Alex
I don’t think so.
Frig does note that the primer cup was nickel plated as an ID.

Alex, you can read more about the propellant issues in the last pages -conclusions and recommendations- of a 1982 report on the 7.62 mm SLAP round:


Fede, thanks!

Why was ARRADCOM developiing sabots in this project? I thought it was an Olin development.

And who is meant with “GTE Walmet Division”? Or do they mean Valmet in Finland???

Alex, Olin was the contractor but the initial specifications, drawings, &c. were made by the US Army ARRADCOM. The Walmet Div. of GTE Products Corp. was one of the sources for the penetrator.

Ok, I was not aware that Olin was just the manufacturer then.