I have a Winchester M70 classic stainless / synthetic rifle chambered in 300 win mag. What is the the most cost effective chambering that would keep gunsmithing costs to the minimum. I'm just looking for a fun shooter at a minimum cost to get into big bores using my donor rifle.

458wm. Same case length so magazine issues are at their minimum.

Jacketed .458" bullets are plentiful and some are cheap and there is a wide selection of cast bullets to further cut costs or molds to cast your own if you wish.

Easy to reload down to 45/70 levels or up to max levels for a wide range of fun.

And when the time comes, the 458wm is a great cape buffalo or elephant round, despite some decades old issues that are now long resolved with modern powders.

JPK

458 AR..

for those that don't know, winmag brass is getting tough to get, and is a SEAONSAL run from winchester.

the .458 is the "best" cost effective bore size
your real choices are 458 winmag .. 500gr at 2150, 458 lott, 500gr at 2300, and 458 AR, 500gr at nearly 2400 ...

and no belt on the AR... brass is like 70¢, made from 375 rum, and just fun to shoot
jeffe

with merely a rebarrel you can have a .375 Taylor, a .375 Ruger, a .416 Taylor, a .416 Ruger, a .458 Winchester and the .375 Ruger and .458 are standard rounds so the cost of converting is less for them.

Winchester sells the parts necessary to convert a 300wm to a 375 H&H/ 416 Rem for around $50.00 & you can put them in yourself. It is worth $50 more to me to have a 375 H&H than a 375 Ruger or a 416 Remington than a 416 Taylor.

I've got two full length magnum guns that started out as standard lenght Classics. Very easy conversions.

I keep reading that 458wm brass "is getting hard to find" or something similar. But the 458wm is my go to cartridge for DG hunting, and I do a good bit of that and every time I go to get new brass for my next hunt I have NO DIFFICULTY finding brass!

JPK

I was thinking the 458 Wim hadn't considered the Lott becuase was unsure about what action components would require replacing. I see shilen do barrels in 458 Win & Lott so would probably order one of those. What barrel contour would you go keeping in mind that I want handy, maybe a 22" barrel length. It's got to be portable but not too light that I get the snot smacked out of me

Rebarrel it to a .458,