I've had several 527s through the years, all were very accurate. I used one in .221 Fireball and 50gr XLC for a shoat, it worked fine. I liked the .223 Lux model a lot, coyotes and birds were zapped very well. I used one in a Varmint, .204 for some awesome prairie dog shots.
I often thought about having that 527 .223 Lux rebarreled or rebored to 6x45mm. I had used a Remington 700 rebarrelled to 6x47mm and used the 85gr XBT for some exotics in Texas. I shot an axis doe, a real nice Axis buck in velvet and about a 500# Scimitar Horned Oryx with it. I was recovering from a neck surgery and the rifle had no recoil ( one of the rules my wife set for me,! ha)I later had that rifle rechambered opened up the bolt face to .243 and gave it a friend in south Africa. I think your idea is a great one Pastor! I never loaded the 7 TCU, but if you can get it to fit your magazine, I say go for it! If you do, we will require you to report on "everything", ha. Good luck to you Pard.