Home Forums Hunting & Shooting Express Rifles and Big Bores Only CZ 550 safari magnum

Typically the BRNO/CZ in 458 would either feed correctly, or not.

I got my CZ550 458 relatively cheap because it was warranty returned by the owner to the dealer and they were going to part it out figuring it was a lost cause to try and fix it. It was relatively new and the dealer had a reputable smith modify the feed ramp when the owner had made complaint but it didn't fix it.

There's something in operating the bolt. I knew the original owner and every round from the LH side of the magazine jammed on him, whereas only occasionally for me.

I use Woodleigh PP projectiles (like a spitzer) and that has almost completely fixed the problem. I accept the occasional jam and can rectify it quickly, but not everyone would be happy with that. A DG rifle needs to be 100% reliable but I have no such concerns with the pigs and rabbits I shoot with it.

Using pointy bullets seated out long will generally feed properly. It’s the factory 510gr Win factory loads and reloads using bluff round nose and flat nose pills that seem to cause feeding problems.

After a lot of work on the mag, mine feeds most pills well including bluff nose cast pills.

Sorry to hear about the feeding situation. Such obviously can be a real problem! I'm no gunsmith! But long ago I learned of the hazards of 'messing' with receiver-integral feed rails & ramps! The relative pernament nature of such work and impracticability to restore metal removed, heat treatment and all!

I have a Sako Mauser 98 based on FN commercial action. Converted from 300 H&H to 300 Wby, but it was accomplished by Weatherby themselves as part of a Sako barreled action purchase from them. It feeds fine. Transaction in the fifties as a teen & still have it!

Such stories are learning/reinforcing lessons!
Best!
John

I had a CZ 550 in .458 Win. I simply handloaded all bullets long: 350 TSX, 400 Barnes X, 450 Barnes X, 500 Hornady, etc. Never a loading issue. It would easily match a Lott in ballistics, then still more free bore.

Bob
www.bigbores.ca

Hope you don't let that one get away from you.
Rechambering from .458 WinMag to .458 Lott would be a crime.
That will not fix any feeding issues that you cannot fix by a front reinforcement of magbox (best done whatever the chambering, whether inside or outside the box)
and adjustment of COL depending on bullet.
As Bob said, the long loaded .458 WinMag easily beats a SAAMI .458 Lott for highest MV/KE at lowest pressure.

As mentioned earlier, factory CZ550 / Brno 602 in 458WM will either feed or not feed. A lot of the factory rifles do but some don’t and mine being a conversion certainly didn’t. Loaded to SAAMI length leaves nearly 0.5” of extra mag length in these long mag boxes. It’s a bit like expecting to have no feeding issues using a stock mag in a SA Rem 700 that’s chambered in 6mmBR. It’s a big ask.

The smith that did my metal work is a very experienced smith. He worked for Century Arms and did most if not all their big rifle builds, including quite a few 500J rifles on 98’s. He was at his wits end trying to get my rifle to feed. In the end, after trying all his usual tricks, he soldered a piece of hard steel inside the front of the mag to shorten the mag length and then blended the top of the metal block to form a longer feed ramp. This has worked.

At the time I consulted with CZ guru Wayne Jacobson at American Hunting Rifles, who BTW was very helpful. He said that of all the chamberings the big CZ came in the most troublesome was the 458WM. He went on to say that the feeding generally improved when rechambered to 458Lott. In a conversation I had with Graeme Wright (of Double rifle fame), he also confirmed Wayne’s findings with problematic CZ’s in 458WM. However, I persisted with the 458WM chambering and the smith has fixed the feeding problem, but I should have just rechambered to 458Lott.

For a safari hunter that wants to take one rifle for DG and plains game I think the 458 Lott chambering does have its advantages. It allows a longer length with shorter pills that you might use for plains game (eg 350gr TSX). Personally, I like my handloads to have a decent amount of the base of the bullet held by neck tension and not just rely on crimping into a pressure relief groove near the base of the bullet. Plus you can still fire factory 458WM shells should you need to. As Ron and Bob have clearly shown, a long col 458WM can exceed 458Lott ballistics at lower pressure, but there are other factors to consider.

I almost went the route of trying a spacer at the front of the magazine but the problem became almost non-existant with the appropriate projectile choice.

A friend with a jamming CZ550 458WM fiddled around with mag spring tension/arrangement with some success. The round leaves the magazine earlier so the angle of the round is less ie it is no longer sharply angled towards the extractor recess inside the front of the action, where the projectiles go to jam. The front spacer arrangement is also meant to help with the early departure of the round from the magazine.

Gents that is some very useful information! Goes to show you can’t take just about any factory rifle as delivered after dangerous, or even any, game without seriously going over it and trying the loads you think you want to hunt with.

Exactly. I'd recommend shooting the Big Game Rifle match down here too. Good experience for practicing rifle handling and reloading under pressure (time pressure at least, not big teeth and claw pressure), as well as discovering any other potential rifle issues.

BGR match is where I discovered that my Merkel 500NE double will fire both barrels if the rear trigger is pulled first. Unfortunately the second goes off a very short time after the first, when it is pointing skyward. And it's not all that enjoyable when that happens either. The spectators got a laugh out of it though.

Some trivia:
The .458 Lott chambering from the CZ-USA outfit that I bought was in a "Kevlar" (B&C synthetic) stock,
so it was one of their later ones, not a stamped-over .458 WM re-chambering.
But it still had the oldest, original CIP chamber throating and was properly marked on barrel as ".458 Lott" with no over-stamping of the "WM."
It had a .458 WM throat on the end of the 2.810" brass-accepting part of the chamber, as per original CIP homologation for .458 Lott.
Makes me think they chambered the barreled actions in Czech Republic and shipped to Kansas City for stocking.
The Motherland of CZ was obsolete on their chambering reamers ?
Or are the chambers hammer-forged into the barrels with the rifling ?
That would be an expensive bit of tooling to change just for the throat.
The latest CIP .458 Lott chamber matches the late-comer SAAMI .458 Lott chamber nowadays.
No confusion with the .458 WinMag, as SAAMI and CIP have always matched on those chambers,
since 1956 SAAMI.

If you re-chamber a .458 WinMag to SAAMI .458 Lott, the .458 Lott throat is swallowed by the .458 WinMag throat.
You will have the same as the .458 Lott wildcat that Jack Lott built.
That is the best kind of .458 Lott to have.
It can be done by hand with a reamer and a T-handle, like Jack did,
with a non-cutting stop in the belt portion of the reamer.

I have no need for that, prefer leaving well enough alone as the .458 WinMag.
Can't fix perfect.

Considering how bad CZ customer service sucks and how many CZ rifles I’ve sent back for repair I’d be an easy pass.

CZ-USA customer service was great for me, while the 550 Magnum and Medium rifles lasted.

They replaced entire firing pin assemblies on a 9.3x62mm (Medium) and another Magnum because I did not like the C-clip spring retainer instead of the
double-nut-locking retainer I had always seen before.
I think they stopped that sneaky move.

They provided the .458 WM mag boxes (no ribs stamped in sides as on the .375 H&H boxes)
whenever I wanted to order some spares.

They replaced a fancy, marble-caked, Phat-American walnut stock on the .404 Jeffery, when it broke off at the wrist.
It happens.
.505 Gibbs did not break the same style stock.
.404 Jeffery broke the stock.
They let me choose "Kevlar" stock as the replacement.
They had to change name of that one to "Aramid" stock due to copyright on Kevlar name, methinks.

And by gosh, I have owned a half dozen .458 WinMag CZ 550 Magnum rifles with no feeding issues.
Wish I had not rebarreled or re-chambered them in youthful ignorance of the greatness of the .458 WinMag.

Maybe CZ-USA were fitting the Lott barrels from new in the US for the more recent ones. The 404s and 505s had US barrels and were assembled in the US, along with the different stocks and the recoil reducers. Front sling studs were also typically on the barrel for those.

True, the .404 Jeffery and .505 Gibbs barrels were made for CZ-USA, by McGowen, button-rifled not hammer-forged.
The marble-cake, black walnut, Phat-American, stocks came from USA too, I reckon.
The .458 Lott CZ 550 Magnum factory rifles that I owned at one time (early one with Lux walnut stock, later one with Kevlar/Aramid stock)
both were like the standard .458 WinMag in barrels.

RC,
WRT the above post mentioning McGowen barrels.

Both my Custom DR rifles have McGowen barrels and both are very accurate.

McGowen barrels are good ones.
Their .458-caliber barrel had a true minimum groove diameter of 0.458" last one I bought from them.
The Pac-Nor was too.
The factory CZ barrels I have slugged are 0.459" like on most .458 WinMag factory rifles, Winchester and Ruger.
SAAMI minimum spec is 0.458" for barrel groove, and maximum bullet spec is 0.459" diameter.
I think my Shilen barrels are about 0.4585" so rounds up to 0.459".

I heard the McGowen factory is making the inside steel tube of carbon-fiber wrapped rifle barrels
for some brand nowadays too.

So I bought the rifle and this morning I discovered it has been rechambered to 458 Lott. I just bought some 458 win mag ammo made by hornady 510gr solids. I then noticed on the box it says “this ammunition is intended for use in fixed breech firearms only” would you fire this in the CZ 550 rifle? I’m not familiar with these big bore rifles.

Good price for a good rifle that can be rechambered for an even longer cartridge if you like. (450 Watts or such).
And, yes, you can fire the 458 Win Mag in a Lott or Watts chamber.

The bolt action must be considered a fixed breech, is the only way I can make sense of that last statement,
as opposed to a break-action where the breech face drops away from the chamber when the action is opened,
as with a double rifle or single shot.
Still, plenty of double rifles have been made to handle standard SAAMI/CIP .458 WinMag ammo,
so I do not understand why the ammo was labeled like that.

Of course, firing .458 WM ammo in a .458 Lott is like firing .44 SPL ammo in a .44 RemMag, etc.

Sorry 500gr-fmjrn is the correct description on the box. I’m also thinking this rifle possibly was rechambered by CZ. It has a very neat stamped 458 lott with a slash / above the 458 win mag stamp on the barrel. Thanks for everyone’s help.