It was invented by a poster with the handle NONAGONAGIN or FOOBAR on the accuratereloading.com forums. I think its the same guy under two handles as both make references to inventing it. The forums are almost dead but NONAGONAGIN was posting as recently as last year. So you might still find him there. I searched a couple threads referencing the project here.
http://forums.accuratereloading.com/eve/forums/a/tpc/f/4711043/m/3411029751?r=8481004851#8481004851http://forums.accuratereloading.com/eve/forums/a/tpc/f/4711043/m/3851050502?r=4071060502#4071060502From 'FOOBAR's' posts
On my last wildcat, my 510 Makatak, I had the reamer made by PT&G, then I cut the chamber, THEN I fire formed 3 cases and sent the reamer AND the fireformed case to CH4D to have the dies made, and requested the sizer be 0.001" to 0.0015" smaller at the base than chamber size INCLUDING springback and 0.002" shoulder setback. They came back perfect even though it took 8 months.
My 510 MAKATAK is a Rigby case necked to 50 cal and shortened 0.050" at the shoulder,0.500" neck length, 2.85" case length, 3.25" COL in the Ruger Tang M77 originally a 30-06. I opened up the bolt face to handle the Rigby case.
The throat is long enough to shoot milspec 650 gr BT's at 4.5" and I'm looking for some cheap ones to try out...another reason why I went with my own wildcat rather than the 500 AccRel. Maybe next year I will do a 30-36" barrel and a build a "roofrest" setup just to "bomb" sageratz at 1000 yds. lol
I tried some 475 gr, 535 gr and 590 gr Beartooth cast lead CG's...the 475 gr with AA2520 chrono'ed ~2330fs at ~40KCUP...with at least ~350-400fs more to go. The 535 gr was slightly over 2100fs with AA2520 but didn't chrono any of the 590 gr...a CG came off and wasted the front Beta Chrony screen while I was testing 458 A loads in my Marlin 336.