Would a 458 Lott RSM be a step up from a 458 Win Mag BRNO? Would it be better just to rechamber the BRNO?

Personally, I like the BRNOs. They're big enough for any practical cartridge and they hold a lot of rounds down (at least 4, probably 5 down with your lott.) There is certainly enough room in there to rechamber to the longer round.

The 602 in particular has a "history" and is synonymous with modern African hunting. I don't know the exact number, but would venture to say that more than half of African PHs either use or have a well-worn 602 in camp.

If Africa rings your bell, then you probably have a soft spot for them too.

A word of advice on rechambering. If it's a 602, your gunsmith should plan on rechambering it with the barrel on.

I don't know what they did to put those barrels on, but it usually takes a lathe and removing steel from the barrel shoulder to get the barrel off of a 602.

I would rechamber your Brno. I have one that was originally a Win now a Lott. They used crush threads on ZKK Brnos so leave the barrel on when rechambering, no need to take it off anyway.

THe Brno 602 is a fine action and I would just re-chamber it. I think the RSM's are a beautiful gun though, my only complaint is the lack of a lug on the front of the action.

Paul Rigby at one point used the 602 action as a basis for his rifles............

I had my cz 550 .458 winnie reamed out to lott, it's a better round for the big cz 550/Brno 602 as it fills the mag bix better, the 458 winn9ie can be in a 30/06 action and is probably better suited to that length action I reckon.

I rechambered my CZ-550 .458WM to Lott. Improved the feeding btw...

There is nothing Brno about ZKK or CZ 550. Genuine Brno rifles are made on polished VZ-24 military action with largest caliber being 9,3x62.
Zbrojovka Brno
These are much nicer then those Uhersky Brod Lunkers!

P/

the rsm is awesome, weighs too much, and anyone with a will (and a milling machine) can cut a slot in the underrib and solder a square lug on...

the brno/zkk/cz are of proper weight for a rifle, and a basically a suped up mauser platform.. value of the improvements are felt to the users opinion

remember, the 602 is more or less the 550 magnum, with a "cocking" safety.. aka backwards

jeffe

Before you run out and re-chamber the 458 to Lott, chronograph some loads through it and you might be surprised. I use the Barnes 500gr banded solids in my CZ550 and 64gr RL7 to get about 2200fps from a 25"+ barrel. The Barnes banded solids give you the option of using the grooves to seat the bullets out further, eliminating powder compaction and increasing capacity. The CZ has a cavernous magazine that easily allows you to seat the bullets way out there.You can easily put a droppped floorplate on it and pick up an extra round in the magazine.

Be careful reaming the chamber with the barrel on the rifle. Some times it turns out ok, sometimes you wind up with a botched chamber. Harry McGowen about had a stroke when I mentioned doing this when I was in his shop. He said he gets a lot of business fixing messed up rechambering jobs that are done this way by ham-fisted amateurs. He only charges $135 IIRC for a Lott rechamber,he takes the barrel off when he does it, money well spent for some peace of mind. Good luck whichever way you go.