The #1 in 458 can be re-bored to 470 NE. Some of the older #1s can be re-bored to 500 NE but they are getting scarce. The later issue Rugers have the quarter rib holes drilled too deeply.

The safety is in the way of the bigger NE cartridges. For the 500 NE, I'm simply shaving and melting my own safety and re-installing it in the factory (exterior) position. The 577 does need to have the safety recessed.

SSK Industries did my 500 NE #1 and I am very happy with it. Unfortunately, they do not re-bore anything, only re-barrel. Mine has a 27" Shilen barrel, 1" straight. Cost was about $1200 USD.

Here is their web site: www.sskindustries.com/

Bowen does a lot of #1s and their rep is also very good. They will re-barrel when appropriate. Their web site is:

www.bowenclassicarms.com/

Holler if I can help and good luck to ya.

-Holmes