I don't know the details but a friend in the midwest had one built, then rechambered it to 7mm STW when that cartridge came along. He's a serious long range game shooter and really happy with the STW, but I simply don't recall why he gave up on the 7mm/300 chambering.
1000-yard match shooters messed with 7mm wildcats for a long time, but I've lost track of that crowd. A great bunch that can teach you what precision long range shooting is all about, but I don't know if they've picked up on the STW or if they're still using wildcats.
Have Had At Least One Of This Chambering For Over 20 Years. I Shoot The Identical Load In It As The 7mm Stw. Since The 7mm Stw Is A Factory Load I Have Gone To Chambering For These. Very Impressive With 27", 12" Twist Barrels. My Load Is Warm At 81.5 Grains Of Rl-22 With 140gr Accubonds Or Balistic Tips.
I had one built on a Remmie 700. I rechambered 7mm mag to it. Dang rifle was amazing. Load was 7828 and 175 partition.
I remember sighting it in 3 inches high at 100 yards and firing 3 shots. Then I moved the target back to 200 and fired three more. Finally I set it up at 300 and fired the last 3.
All 9 fit into a 5 inch circle!
One of the few rifles I ever regretted selling.
In todays time I would start with 175 grain XXX and RL 25 and see what develops.