The .358 WInchester - An Interesting Cartridge

[gitano]

As some of you know, I think a great deal of the .308 Winchester case. There aren't any cartridges made from it from the .22 Cheetah to .375-08 that I think aren't at least "reasonable" hunting cartridges. Since I am building a .358 Steyr (a .376 Steyr necked down to .358"), I thought I'd have a look at the .358 Win and see how it performs (on paper) relative to the .358 Steyr. As usual, it was an interesting journey. (All of the following calculations are from QuickLoad unless I note otherwise.)

I should define my personal design criteria first:

1) Muzzle energy of less than 4,000 ft-lbs, and less than 3,500 ft-lbs is much better,
2) Carry 2000 ft-lbs (and not a lot more if ME goes up over 3,300 ft-lbs) out to 300 yds, and
3) Not be more than 9" low at 300 yds when sighted in for a 6" target - (not exceed 12" of total vertical deflection).

When it comes to bullet seating depth, I prefer to seat one caliber deep. I'll settle for 2/3rds of a caliber (67%) if it will help to keep the max chamber pressure below the max spec'd and still keep the other numbers up where I want them.

According to SAAMI, the max AVERAGE chamber pressure one should have in a .358 Winchester is 58,740 PSI. Since I like Mauser 98-type actions, I set the limit at 56,565 PSI.

Using a 26 inch barrel I get the following numbers with a 1-caliber seating depth for a 225-grain Nosler Partition:

Loaded Cartridge Data:

................Powder: I3031
................Charge: 45.2 grains
Chamber Pressure: 51,343 PSI
.....Muzzle Velocity: 2515 f/s
......Muzzle Energy: 3160 ft-lbs

Trajectory and Retained/Delivered Energy Data:

Range in Yards . Elevation . . Energy
100 . . . . . . . . . . . 2.8" . . . . 2727 ft-lbs
120 . . . . . . . . . . . 3.0" . . . . 2646 " "
200 . . . . . . . . . . . 2.9" . . . . 2342 " "
213 . . . . . . . . . . . 0.0" . . . . 2295 " "
250 . . . . . . . . . . .-3.0" . . . . 2166 " "
300 . . . . . . . . . . .-8.6" . . . . 2000 " "

Now by my way o' thinkin' folks, that ain't too shabby. I get a nice short cartridge that:

1) Generates a very tolerable muzzle energy at a "nice" chamber pressure more than 7,000 PSI below SAAMI max,

2) Carries 2000 ft-lbs out to 300 yds, and

3) Is less than 9" low all the way out there at 300. (Total vertical deflection less than 12" in 300 yds.)

I'd hunt with a rifle/cartridge combination like that any day for anything on the North American continent, and most of what's in Africa.

And such an "old-fashioned, wimpy", cartridge it is too. Not nearly as "ehtical" or "cool" as those new "super" cartridges.



Paul