Ming, You're my action hero!

cz550 & olympic arms ultramag

Good options for us poor folk.

The Ultramag sure looks crude when compared to the CZ550. Perhaps with a few hours on the Buffer it would clean up ok! I believe the Ultramag is in reality a BBK-01 or 02 ( they didn't seem to know when I talked to them). For $600 I'd take the CZ.-Rob

My ultramag has a 0.720" bolt body diameter, if that helps identify what action it really is.

The queer thing is that they drill and tap it for Browning A-bolt scope bases. And the bolt is swept back too much. And it looks like it was spray painted.

500 grains- Sounds like a BBK-02. I have one with a .730 bolt diameter on a custom .416 Rigby. That's about the only good thing I can say about the action. As I remember, I had to mill flat a set of warne bases to fit the thing. I spent about 5 hrs trying to polish mine before I blued it. It also took a mottled color on blueing which makes me suspect of what alloy they used. I believe they are investment castings. -Rob

Thanks folks for the comments!

Yeah I like the finish of the CZ 550 better. I do not like the UltraMag BBK-01 being drilled and tapped for the A-Bolt pattern mounts. According to Dennis Olson's own testing, the Ultramag BBK-01 is a very tough action so it should be good for a big bore cartridge like the 505 Gibbs. This BBK-01 has a .725 diameter bolt. As for the finish, it is in the raw casting finish but with some polishing work, it should come out nicely. Got to love that three position safety. Later.

Mingo-Rob-That BB-2 would be great for the 600 OK
with the larger diameter bolt.They are tough.
I remember someone somewhere saying they were
investment castings as tough as Rugers.Ed