I want to make some experimantal loads for my 458 win mag, 325gr at about 1800 fps. This is not a typical load so I am having some trouble finding actual data for it. I can do some estimating.
Is there some calculator I can look up or buy or something?

Thanks.

Ken Waters' "Pet Loads" book lists 68 grains of Reloader 7 behind a Hornady 300-grain HP as giving 2158 fps, and a 350 Hornady RN giving 2122 fps with 69 grains of the same powder. I would think you shoould be able to extrapolate a starting load by beginning somewhere in the middle of these, and working up.

You need to research the Lyman Cast Bullet Handbook, old IMR data from the brown booklet from the 1970s and 1980s (for IMR4227 and SR4759)
and the Speer Manual for SR4759.

You can also look at the Speer Manual for the high pressure 45-70 loads that us SR4759.

If you do not have these references post here or send me a PM.

I can recommend SR4759 from long use in BPCRs - mostly 45-70s. It is a very bulky powder that takes up a lot of space in the case making it work pretty well for reduced loads.

XMR5744 is another powder with similar burning characteristics but burn dirty. It is intended for reduced loads. You can find that data on the net in some cases. It was once an Accurate Arms powder. It is now called Accurate powder and is marketed by Western powders.

IMR4227 also has similar burning characterists but is finer grained that SR4759.

Can you tell us what the goal or objective of your load is?

Most 45 cal rifles will be more accurate at low velocity with the heavy bullets.

quote:

You need to research the Lyman Cast Bullet Handbook

I am holding my copy of the Lyman Cast Bullet Handbook. The only bullet weights it lists are 292 grains, 385 grains, 482 grains, and 562 grains. In other words, extrapolation is needed for the 325-grain projectile the OP is looking to load...

The Lyman 45th Reloading Handbook lists a 385-grain bullet as the lightest. More extrapolation necessary...

The 13th Speer book lists 4759 with only a 400-grain projectile, and stops at 30.0 grains max. Speer #8 doesn't list the 458 at all, and #11 starts the loads at 400 grain bullets...

The first Sierra manual doesn't even list the 458...

The 1970 Hodgdon Manual #12 lists H4198 ONLY for the 300, 350-grain and 400-grain projectiles.

The RCBS Cast Bullet Manual probably comes closest, listing a 311-grain projectile as being loaded with 21-23 grains of Unique, 46-50 grains of IMR 4198, 58-62 grains of IMR 3031, or 58-62 grains of IMR 4064.

I hope some of this helps...

quote:

Originally posted by SR4759:

Can you tell us what the goal or objective of your load is?

.

The plastic tipped Hornady FTX bullet is fairly light and still has a good b.c. I was hoping to get a good deer and plinking round that has modest recoil and relatively flat trajectory.
I might be asking a lot of this caliber.

quote:

Originally posted by SR4759:



I can recommend SR4759 from long use in BPCRs - mostly 45-70s. It is a very bulky powder that takes up a lot of space in the case making it work pretty well for reduced loads.

I have a can of 4759 right here. A bulky powder would be a good thing.

About 35 grains of SR4759 ought to be just about right on what you need.

But, if your gun fits you, the Hornady 350 at 2100 fps is a real easy shooting load that will whack any deer or pig you see out to 150+ yards without much, if any, holdover.

LWD

Great suggestions.
Now, I have a question. If I start with 35gr of sr4759, and I start stepping it up looking for a group, will I first hit pressure, or run out of case capacity?

quote:

Originally posted by LWD:
About 35 grains of SR4759 ought to be just about right on what you need.

But, if your gun fits you, the Hornady 350 at 2100 fps is a real easy shooting load that will whack any deer or pig you see out to 150+ yards without much, if any, holdover.

LWD

You will hit pressure long before you run out of case capacity with SR-4759. It's bulkly but we are talking the 458 Win Mag case here.
With a 425 grained cast bullet from 30 grains to 42 grains yields from 1450fps to 1872fps with SR-4759
51 grains of AA-2015 with the same bullet is a nice soft shooting accurate load guessing 1700-1800 fps.
With the 405 Remington jacketed bullet: 52 gains of H-4198 will give about 1950fps. All of these loads are pretty soft shooting and will kill all the deer/ hogs you want to shoot.

quote:

Originally posted by frank4570:
Great suggestions.
Now, I have a question. If I start with 35gr of sr4759, and I start stepping it up looking for a group, will I first hit pressure, or run out of case capacity?

quote:

Originally posted by LWD:
About 35 grains of SR4759 ought to be just about right on what you need.

But, if your gun fits you, the Hornady 350 at 2100 fps is a real easy shooting load that will whack any deer or pig you see out to 150+ yards without much, if any, holdover.

LWD

I don't know. IMR lists 44.5 grains behind a 500 grain jacketed bullet for 1645 FPS at 52,400 CUP. That amount of powder will take up about the same space as 55 or 60 grains of fine grain extruded powder. You can try it by pouring 45 grains into a 458 case and taking a look.
You can also imagine how much it will take to build 52,400 behind a bullet that weighs about 55%. Say as a swag it is 55 grains - that might be equivaent to 70 grains volume with other powders.

No matter what trick you try with that light bullet it is going to require a lot of hold over at 200 yards. Find one of the trajectory calculators on line and put in your desired information.

One thing you might keep in mind is the throating of your .458. If it is a SAAMI chamber it will have a really long leade - it is a DGR.
That long leade will make accuracy possibly suck with short bullets.
You can look at the SAAMI drawings on line if you do a search.
Your rifling twist is probably 1 turn in 14" which is way fast for even 500 gain bullets.For example 45-70 BPCR match rifles are usually 1 in 18" and are expected to shoot 525 grain bullets at 1100 FPS to 1000 yards with accuracy.

40-42 grains of Accurate 5744 with a magnum primer should give around 1800 fps with a 325 grain bullet. No fillers needed with this powder, just load and shoot.

frank45/70

I have killed a deer and 2 pigs with the Hornady 325FTX bullet out of a 458 SOCOM and it worked great. My muzzle velocity is just a little over 1700fps, and I still got expansion on a deer at 141 yards.

Here are some loads for the 458 Win Mag from Ken Waters.

300gr bullet:
50gr of IMR 4198 1863fps
60gr of IMR 3031 1902fps

400gr Speer FNSP:
56gr of IMR 3031 1564fps
60gr of IMR 3031 1766fps

I would start with 58gr of IMR3031 and work up for best accuracy.

I always used IMR 3031 in my 458's.

I think you idea of a 325FTX at @1800fps is a great one. It will make a great deer/pig load.

That is one of the advantges of the 458 Win Mag, there are a lot of great bullets avialable for lighter loads, suitable for lighter game and for plinking and practice.

Invest ($153) in the Quickload Windoze program. It will let you do all sorts of experimentation, with or without having fired rounds.

Quick Load

You definitely can get too much SR4759 in the 458 Win Mag case and have a pressure problem so be careful. Anything under 44.5 grains ought to be safe though. That's a max load with a 500 grain bullet. There's not a lot of, if any, risk of a detonation with light loads of SR4759 in a large case, but I've also never seen loads of it less than 30 grains, so I'd start there and work up.

But I think you need to be a little careful with this bullet.

In looking at the current Hornady data, it seems the 325 FTX has more bearing surface than their 300 grain bullets. In the 450 Marlin, the starting and maximum loads for the 325 FTX are markedly lower than the loads for their 300 grain bullets.

Also note that the case trim lengths for the FTX bullets across the spectrum of bullet weights are shorter than for non-FTX bullets. The stated reason for this is that the bullet has a longer ogive. I.e. it could get into the lands and cause a pressure spike.

So perhaps you need to be a little more careful with this bullet than others.

And there are other choices out there that don't have these issues. The Hornady 300 grain intro loads are at 1850 fps. The Hornady 350 grain intro loads are 2100 fps.

That said, Modern Reloading #2 lists a max charge of Herc 2400 of 35.0 grains for a 300 grain bullet at 1590 fps with pressure of only 13,500 CUP.

Let us know how it works.

LWD

quote:

In the 450 Marlin, the starting and maximum loads for the 325 FTX are markedly lower than the loads for their 300 grain bullets.

When used in a Marlin the overall length is restricted so the long pointy nose requires the bullet to be seated deaper than a 300 grain.

quote:

Originally posted by LWD:
But, if your gun fits you, the Hornady 350 at 2100 fps is a real easy shooting load that will whack any deer or pig you see out to 150+ yards without much, if any, holdover.

I use the Speer 350 and 57g IMR 4198. That is below the Hogdgon online data, maybe I found it online or in a Speer book. It recoils the same as the 30-06 I shot with it.

Anyway, you inspired me to do some ballistic comparisons of the 325 Hornady FTX, the Speer 350 flat point, and the 300 Barnes TTSX. The ballistic coefficients are all very close (.230-.236.) Comparing 100 yard zero and 300 yard drop, they all drop about 22 inches at maximum velocity, and about 36 inches at 2100 fps.

My point, don't be afraid of the cheap and available Speer 350, if availability or data are hard to come by for the FTX. None of them are what I would call 300 yard loads. All would work on deer. I killed 3 deer in the last two seasons with the Speer 350 and 57g IMR4198, and I am happy with performance.