If using the factory stock, you will need to custom profile a new 721 barrel.
Sweets darn sure eats brass jags and brushes.
I about damn near wore the barrel of my 7 mag trying to get it clean.
I used sweets, then an overnight soak with Hoppes, followed by brushing.
Another shot of sweets always brought out green. Repeat, repeat, for days.
Finally realized the brush and jag mixed with Sweets was causing the green.
Who knows how long the gun had been clean.
