Rechambering Model 70 Safari Express in .458 Win Mag to .458 Lott

100.jpg


Take a gander at how the exactly same powder charge in a .495 A-square beats a .500 Jeffery with exactly same barrel (26", 1:10" twist) and bullet weight, 570-gr:

.495 A-Square: 104 gr of H4895 >>> 2406 fps, sub-Pmax and most uniform of all for pressure SD/ES

zzzz000.jpg


.500 Jeffery: 104 gr of H4895 >>> 2348 fps, exceeds Pmax and wildly non-uniform for pressure SD/ES

zzzz01.JPG
 
That's just because you're running the 500 jeffery at the original 1920 pressure levels. With a strong action and new brass you can easily attain 2500 fps with a 570g bullet with the 500 Jeffery.
 
Yeah, right.
Still shows that the li'l .495 A-Square can beat the "classical" .500 Jeffery jumbo-killin' ballistics,
and does it with less recoil for whatever ballistics if same MV with same bullet as the .500 Jeffery.

Yes, comparison point here is the 3300 bar MAP for the .500 Jeffery versus 4400 bar MAP for the
.495 A-Square.
And those are modern pressure standards of CIP, not 1927 vintage.

Higher pressure does the trick, and that may be a key to the uniformity and efficiency of the .495 A-Square.

Wait until that .495 A-Square gets a .458 WIN MAGIC throat and becomes the ".510 WIN MAG."
That will add another 100 fps to MV at same 4400 bar MAP.
Slicker feeding than a .500 Jeffery.
And the .510 WIN MAG reamer would be perfect for re-throating the no-throat, short-necked, rebated-rim .500 Jeffery.
 
SCAN0202.JPG

That will work in an M70 Winchester with 3.6" magazine box but that will cramp the nose room just like in a .458 Lott, tisk, tisk.
If you scale up a .458 WIN MAG to .510 caliber, that 3.340" COL becomes 3.720" and really ought to go into a 3.8" magazine box.
Best use for a .458 WIN MAG M70 Winchester rifle
is to leave it as is, .458 WIN MAG.
 
You must log in or register to reply here.

Members online

... and 1126 more.
Total: 59,592 (members: 1,176, guests: 58,416)

Forum statistics

Threads
65,319
Messages
1,441,416
Members
135,568
Latest member
DoziSezal
 

 

 

Proudly sponsored by

Latest posts

Latest profile posts

crossfire3006
crossfire3006 wrote on Hornedfrogbbq's profile.
An excellent AH member right here! I had a fantastic transaction with Hornedfrogbbq (I was the seller). His communication was first rate, payment was extremely fast, and I would have absolutely no reservations at all dealing with him again. Thank you, F!
•••
HENRY GRIFFITHS SAFARIS
HENRY GRIFFITHS SAFARIS
Here we are, the last day of the show in Denver, it's been a good show but expecting a quiet day today. I will be back for-sure to do this show next year and maybe also do the one in Sacramento California.

On Monday I will be hitting the road driving from Denver and eventually make it down to Atlanta for the flight home.

its going to be a good year!
•••
C
CraigV wrote on Rem280's profile.
Hi Rem280, Saw your post on getting selected for Idaho Elk. Do you have a zone(s) selected? I live in N Idaho, might be able to offer some ideas.

Cheers,

Craig
•••
G
ghay wrote on Konrad.inc's profile.
Do you still have the Ruger 9.3x62?
•••
HENRY GRIFFITHS SAFARIS
HENRY GRIFFITHS SAFARIS
I have made it to Atlanta this morning, few other outfitters on same flight and our luggage never came trough, looks like mine will go via France to Denver hope it gets there before the ISE show starts on the 8th TOMORROW!



flying to Denver in an hour! is it to early to hit the bar:)
•••

Share this page

 
Top