I did find this. It’s called .30 HRT. Short for Herrett rimless tactical.
30 HRT Cartridge Details
ar15barrels.com
From your link...and for folks intrigued. .30 HRT is a 6.8 SPC bumped to .30 cal with the same shoulder used on the .30 Herrett using .30 Herrett dies. So its Herrett in name only...compliments of using .30 Herrett dies to do the forming operations.
" ...The 30 Herrett
originated as the product of Steve Herrett and Bob Milek in 1972 for chambering in Thompson/Center pistols. Cases for the 30 Herrett are formed from 30-30 Winchester cases. ..."
"... The 30 HRT is a very simple wildcat based on the 6.8 Remington SPC and 30 Herrett.
For all the people that wondered why 6.8 SPC was a 27 caliber instead of a 30, this is your cartridge.
If you want something with more oomph than a 300x221, this is the answer.
30 HRT is easily formed by full length sizing 6.8 SPC brass in a 30 Herrett die.
Then you simply load using 30 Herrett dies.
It is not available in featherweight or lightweight barrel profiles.
30 HRT uses 6.8 SPC magazines available from
PRI.
30 HRT uses a 6.8 SPC sized bolt head."
From the pic, the intent was to bump the shoulder along with upsizing the neck. I'd be interested in what the case OAL might be as the 2 look real similar in length. I might also be interested in how available the 6.8 brass is if I were reloading it... RCBS and Hornady still peddle .30 Herrett dies so that's not a hassle. The other Q I might ask is reload info availability in current manuals. I'm a tad leary of internet info on the subject for good reason...too many nimrods posting dangerous/misinformed info.
Handy part in all of this for the reloader is that it uses .30 slugs instead of the .27 as with the 6.8 so one can minimise the type slugs in inventory, the downside is that its a wildcat and most tend to die on the vine after the "newness" wears off, and the "big boys" like Remchester come up with the the lastest new and improved after a nod from Guns and Ammo magazine...