Does anyone have a load or suggestion of what powder to use and where to start working up a 458WM load for 450 gr North Fork soft and solid?

Bunch 'o fellows say AA2230 headed up to book max. I'm using that formula and its very accurate but I don't chrony so I don't know how fast.

I use 74grns of BenchMark2 powder for 2150fps with the 480grn woodleigh bullets and have loaded similar for 450grn Swift A Frames.
This powder is Australian made and shows minimal signs of temperature related problems.

I've been using 72 grns. of H4895 w/Fed 215 primers under a Barnes 450 grn. TSX bullet. Outstanding accuracy from my CZ with velocity at 2225 fps.

I use stubby bullets (heavy for length) in the Win mag. I like the NF's but they are long; but not as long as Barnes bullets.
Two accurate loads I have used are.
1) 450 Swift A frame; 74 gr AA2230; Fed 215; Chrono's about 2270 FPS out of my 24" pipe- Is extremely accurate.
2) 500 Hornady DGS; 72 gr AA 2230; Fed 215; Chrono's 2160 FPS out of a 24" pipe.
Shoot to the same POI as the first load. I see no compaction with these loads but they are 97-100% to capacity. No issues with pressure in these loads in my rifle in +100F ambient environment.

I get 2206 fps with 450 grain A-Frames with 74 grains of H4895. It is about as compressed as a load can get, but shot cloverleafs and killed 10 water-buffalo for me.

Since then, I was finally able to find some A2230. 74grs matched the H4895 velocity with no pressure signs what-so-ever, and without the compression. Accuracy was only fair at 74 grains but as I creeped the charge up to 78 grains it returned, and the chronograph was reading 2350 fps. That charge is firmly in the "You're on your own category" but is safe enough in my stock M70.

Not that you asked, but I was also able to get 2150 with 500 grain Nosler Partitions with 72 grains of A2230. I lost most of my interest in buying a .458 Lott reamer after getting these A2230 results.

Thank you gentlemen, it would appear that I should be OK if I use AA2230 and begin at 69 or 70gr and gradually move up with a ceiling of 74 for 450 gr bullets and 72 for 500's. assuming no signs of over pressure.

quote:

Originally posted by TerryR:
Thank you gentlemen, it would appear that I should be OK if I use AA2230 and begin at 69 or 70gr and gradually move up with a ceiling of 74 for 450 gr bullets and 72 for 500's. assuming no signs of over pressure.

465H&H

I use H4895 as some mentioned above.

Superior has put mine together for me, but Mike Brady of North Fork (at the time) recommended H 4895 and AA 2230. You might try sending him a PM here.

These were both with NF 450 grain FPS.

I chronographed 450 NFs at 2250 fps from my 22" barrel with F215 primers and 72 grains of AA2230. The same load gave 2200 with 500 grain Barnes bullets. No signs of pressure and very little powder compression in Winchester cases. Work up to these loads with caution because your situation may be less forgiving.

I like the 450 instead of 500 grain bullets because felt recoil is a lot less. Flat point 450s develop supercavitation and penetrate deeper than 500 grain round-nosed solids.

I tried H4895, VARGET, H335 and AA2230. AA2230 is the best but hard to find.

Could I get more velocity with more than 72 grains? Who cares? Lengthwise penetration on buffalo was most adequate.

Thank you to all that share their information on this site. I just got a 458 WM M70 Safari Express and the information here is perfect advice.

Using 72 gr AA2230 and 450 gr SAFs I got avg. velocity of 2254 fps and a 5 shot group in 3/4"

Did see odd results with 70 gr at 2224 fps but 71 gr was 2219 with lower min and max than 70 gr. Any explanations out there?

After combing through a small sample of the Terminal Bullet thread the next project is to load up CEBs.

Could be any number of things..
1) Same primers?
2) Same brass?
3) Crimped/not crimped?
4) Same ambient temp every test?
5) Barrel allowed to cool between shots equally?
6) Barrel cleaned or fouled between sessions? Clean and fouled barrels show different velocities
7) Consistent placement of Chrono.?
8) Same OAL?
9) Same lot of powder?
10) If you are using a digital powder scale; check it often. They are not always reliable.

quote:

Originally posted by hunt99:
Thank you to all that share their information on this site. I just got a 458 WM M70 Safari Express and the information here is perfect advice.

Using 72 gr AA2230 and 450 gr SAFs I got avg. velocity of 2254 fps and a 5 shot group in 3/4"

Did see odd results with 70 gr at 2224 fps but 71 gr was 2219 with lower min and max than 70 gr. Any explanations out there?

After combing through a small sample of the Terminal Bullet thread the next project is to load up CEBs.

All are identical for all 3 loads. The only real variables not controlled would be barrel fouling and temperature.

I shot the 70 first, then 71 then 72 so if it was a temp sensitivity it should have went up a little more than usual (rather than down for 71 gr) and I do collect data from the chrony between loads and change target to let the barrel cool.

I'm not really concerned about it, just curious more than anything as I have not seen this before other than at max load which is clearly not the case since there were no pressure issues of any kind for the 72 gr loads.

Just curious, but what is the OAL you used with AA2230 and the 450gr A-Frame?

3.287" on the most accurate 72 gr load. Crimped just in the groove. The load didn't seem very sensitive to seating depth in my rifle so I never really messed with any variation.

Here is some data from today.

DISCLAIMER: THESE LOADS ARE SAFE IN MY RIFLE. I WORKED THESE LOADS UP WITH DATA I PREVIOUSLY USED AND BASED UPON PUBLISHED LOADS. REFER TO PUBLISHED DATA.

New Hornday 458 Win. Mag Brass: Size, trimed, etc.
Winchester Mag. Primers.
North Fork 450 grain Softs and FN Solids.
COAL: 3.305 FN Solids and 3.360 Softs
Pownder: AA2230 - 72 grains
Crimped - Lee Factory crimp Die
Temp: 50 degress F
Rife: Browning Safari (1964 FN Long Ext) 24" barrel.

Nominal 2300 fps 8 rounds all within 8 fps. Accuracy potential looks good.