Other than having to ream the chamber for the longer round, are there other things that will need to be done to the rifle in oreder to make it a reliable conversion ?

The magazine box and/or feed rails will need to be modified in order to make it feed the longer shells.

Matt V.

Did you have this conversion done on a CZ 550 to know this for sure ?

generally the 550 works better converted to lott than as a .458. Try and do a rapid fire with a 550 with soft points in .458 Lott

I have one converted from .458wm to Lott. It took about 5 minutes with a file on the feed rails to make it feed any style or weight bullet
Dave

quote:

Originally posted by tank:
Did you have this conversion done on a CZ 550 to know this for sure ?

I’ve owned two…..

When CZ first brought them out “458 Winchester Magnum†was still stamped on the barrel & they just stamped 458 Lott underneath. CZ simply took their old Win Mags and reamed them out to Lotts without opening up the rails. Neither of mine would feed a full length Lott round. The cartridge case heads would not be released in time from the magazine box and cause the action to jam.

It’s a relatively easy thing to fix. But I’d hire a good smith, ya don’t want to remove too much metal!

Matt V.

Thanks for the info.

trophyhunter5000 or anyone else, Does anyone know if the barrel has to be removed on a CZ 550 in order to ream the chamber out from 458 WM to 458 Lott ?

I know some people does it, and it is ok to do so - actually I think Jeffeosso is one of them - personally I like to remoove the barrel anyway, as I find it easyer to polish the chamber afterwards - and remooving the barrel is really no big deal.
I have never done a 550, but quite a few 602's.

Thanks for the info. I have found a gunsmith tto do the work and he will be removing the barrel. I have the 458 Lott reamer and a throater on the way so that I can have a longer throat cut than what the sammi spec reamer will do. Anyone have any suggestions on how much throat or freebore is ideal ? I was told by the guy at reamerrentals.com that their reamer cuts a .178 inch throat. I think I read somewhere that a 458 WM has a .451 inch throat. If this is so, should I go with something close to the .451 of the wm or what ?

On my 458 lott conversion, I loaded up a dummy round with a 500 grain Sledgehammer (long and very straight sided before you get to the olgive) and then instructed the gunsmith to put .600" free bore in front of that per Atkinson's recommendation and per the article by Lott/G. Sitton.

Pounded an elk with it this last fall at 160 yards, right on the money with 450 grain TSX loaded warm, no pressure signs at all.

Also, my gunsmith worked the feeding rails and the ramp, plus slicked up the action.