Could you rechamber a .458 Win Mag in a Mauser action to Lott?

Also, I've read about High Energy factory loads in the Win Mag that duplicate Lott ballistics. Is this true? Who makes them? And, can you "roll your own" to these ballistics without blowing yourself up?

GAHunter,

You can easily do this rechambering. Getting feeding "right" is more involved (solids will probably feed OK and softs will probably need some help). YMMV, as will cost.

Check out the Hornady Heavy Magnum load.

jim dodd

Yes, you can rechamber the Win. Mag. to the Lott. It's done all the time. As Jim says, feeding will have to be tweaked in all probability.

Also as Jim says, Hornady makes a "Heavy Magnum" .458 Win. Mag. load that reportedly gets over 2,200 or so with a 500 gr. bullet. That's pretty close to a Lott, but still 100-150 fps behind.

But Hornady uses a special powder and loading technique (they reportedly "spiral" the powder into the cases using some kind of drop tube/powder funnel device) that handloaders can't duplicate.

3.600" minimum magazine, more is better (Think long monometal solids)

The 458 M70 Classic is fine, most later ones are the 375 H&H length action with the shortened rear bridge. And most of the Safari Express actions come with the Williams bottom metal. If the action is not 375 H&H rear bridge length, it should be machined to this length for proper ejection. How can you tell? 375 length actions have a .330" spacing on the rear scope base screw holes.

Keep in mind most Lott chambers are the American short version, I recommend chambering for the international chamber so it will take 2.85" length brass. Search in Big Bores for more info on this.

In addition to the rechamber, required for one of these actions in 458 Win Mag to convert to to 458 Lott:

Install the longer magazine (or remove the spacer in the 458 Win box), longer follower (the M70 416 Rem follower works great), and either replace or shorten the ejector and the bolt stop. Recontour the ramp and tweak the rails.

Highly recommended: Good pillar bedding job, true the rear face of the barrel mounted recoil lug, install a NECG Masterpiece front ramp, hood & blade, check the cross bolts and secure with epoxy. If not equipped, install Williams bottom metal. If the rifle has the NECG island rear sight with no windage adjustment (it adjusts with a punch and hammer!!!!) install the NECG windage adjustable sight. And, replace the extractor with one machined from solid steel.

IMHO,

it would be wise to start with a cz 550 my overall chamber length is 2.87" my smith staes as that is the specs from clymer reamers. You have plenty of room to use whatever bullets you want and you also have a six shot capacity. The .458 lott also recoils reasonably hard and you will be glad of an extra little bit of weight that the cz 550 has. Once you seat 510 gr win softs out to the cannelure there is not a hell of a lot of room left either.

The M-98 Mauser will make you a wonderfull 458 Lott...Get a Drop Box magazine from Blackburn and go from there...

Ray,

Where can I get the Blackburn bottom metal?

Blackburn bottom metal:

Call the information operator and ask for Blackburn Machine Shop in Spanish Fork, Utah.

It is very likely that you will need a new stock for that bottom metal. Definitely if you get the extra deep bottom metal to fit 4 cartridges down.

And be sure to buy a follower from Blackburn to match that bottom metal because a standard mauser follower is too short.

[ 10-30-2003, 19:09: Message edited by: 500grains ]

John Ricks, I have have looked at several M70 Classics and they are all the same length between the receiver rings, except of course the short actions. Specifically, I have checked, 375H&H, 300 Win, 30-06, 270, 300 RUM, 7mm STW, 458 Win, 416 Rem, 25-06. The ONLY difference was in the magazine box. The rifles chambered in cartridged with COL of 3.34" had a spacer in the back of the box, while the longer COL cartridges did not. The scope mounting holes are the same too! In all honesty, to convert a 25-06 Win M70 Classic to 458 Lott, duplicating what the factory would do anyway, you would simply replace the follower, magazine box, and open the bolt face. Heck there did not even appear to be a significant difference in the feeding ramp between all these rifles!

Are you sure about the M70 classic, or are you talking about the M70 pre64?

Kent

Kent, he's talking about the current production model 70 classic (controlled feed). It is an easy conversion, but easier if you start with one in a long magnum like 7mm stw.