I had one a few years ago and this rifle feed about anything you put in it
tries even empty case, bullet base forward just to try to make it refuse to feed
the cone breach really helps in the feeding department
I am waiting for my new winchester safari express in 458 hope it the same for the reason I load a lot of cast bullet with large meplat for hunting
could the owners of winchester safari express share their experience on feeding with this rifle

Yes, coned breech like a Springfield M1903.
It has an extractor cut in the right side of that cone.
Feeds well as long as there are no sharp corners or edges on that extractor cut where a soft-nosed bullet can hang up.
Some will criticize it for gas handling like the Springfield, if a case head ruptured.
But it does not make the rifle more prone to case head rupture.
Overall, the M70 gas handling is swell, IMHO.

You are a wise man to make that new Winchester M70 a .458 Winchester Magnum.

.458 Winchester Magnum Perfection
Nota bene: In maxima potentia parvum spatium.
Id venit et vicit omnis.
The longer load plus higher pressure is a Lott of fun.
But three point three four and sixty thousand will get it done,
if the rifle is chambered for the four five eight Winchester.
Believe the Three Mahohbohs, or you're a monkey's sister.

if it hang up on the sharp extractor cut is it wise to polish them just a bit or they will polish themselves by loading and break in period I alway load from the magazine

With factory rifles I have never had a problem. Knock wood.
The custom re-barrel needs to specify attention to polishing and smoothing all edges and corners of the extractor cut.
The barrel needs to be off the rifle to do a correct job.

happy to hear

The M70’s that I have and/or had, are as a whole the smoothest feeding of my bolt rifles.
They feed fast or slow. That goes for the various WSM’s through 416’s that I have personal experiences with.

There can always be an anomaly be as a whole they feed excellent as factory rifles.

Yes your rifle has a cone breech as do all M70s with claw extractors, old or new, but don't for a minute think they are smoother feeding than the flat breech post 64 type.
Doubt it? Come over and I will let you shoot a dozen; 6 of each Three of them 375 safari mags, and you will see which is smoother.
Yes, Model 70s are the smoothest feeling; and the flat breech type is the smoothest. I will get hate mail for saying this, but I can prove it.
Cone breeches, like the 03, 1917 Enfield (P14 has a flat breech), and Model 70s, to name the most common types, are good actions, but so are other designs with flat breeches.

had a winchester push feed that did not feed well fast cycling