Subsonic 458 win mag

[generalzip]

I am looking to see if anyone has loaded 458 win mag to subsonic levels successfully? I have a 458 win mag with a suppressor and some ACME 576 casts I was hoping to load down to subsonic for use on hogs and practicing. Haven’t found much online. Some claim to have done it with unique or trail boss but I’ve not seen any load data. Just curious if it’s possible to safely do by seating the bullet deeper.

 

[Fordy]

Gday generalzip
Trail boss has been very good over the years @ obtaining low velocities with no pressures now I’ve got no data on the 458 sorry

Here’s the information off the ADI website

& also ar2206h maybe possible for you to do a reduced load but once again no 458 information sorry

Hope that helps
Cheers

 

[thriller]

I am looking to see if anyone has loaded 458 win mag to subsonic levels successfully? I have a 458 win mag with a suppressor and some ACME 576 casts I was hoping to load down to subsonic for use on hogs and practicing. Haven’t found much online. Some claim to have done it with unique or trail boss but I’ve not seen any load data. Just curious if it’s possible to safely do by seating the bullet deeper.

I have yet to find subsonics that work well on hogs from 308-45/70. Let me know if you find something that works well. Good luck

 

[generalzip]

I have yet to find subsonics that work well on hogs from 308-45/70. Let me know if you find something that works well. Good luck

Have a look at discreet ballistics

 

[Sarg]

I have used subsonic 45/70 loads on a LOT of game up to Buffalo (brain shots) if you use a 500gr slug with a big flat Meplat it will flatten Pigs for sure even 400gr if your rifle doesn’t group the 500gr slugs !

The same load I use in the 45/70 would work in the .458Win but I mainly use a discontinued ADI powder of AP90 it was a high performance pistol powder 12.5gr & a small ball of Dacron pressed down to hold powder near primer, I have used Backer Rod lately in my experiments with my new subsonic 50/70, still on going.

Usually 125yds is max to hit game but now days with a range finder & graduated scope im sure you could stretch that out a bit ?

That slug will just poke a hole through both sides from any angle but I don’t think a stopper unless you shoot them in the Brain Box bud, find a slug from 400gr 450gr 500gr or even 600gr with a huge flat nose that will work even with body shots .

 

[wildwilderness]

I found this-

https://hodgdonpowderco.com/wp-content/uploads/2023/04/subsonic-data-final-1.pdf

That has load data for the 45/70 which might translate to a 458 win.


Remember for subsonic you want to do the “opposite” for reloading- start higher than you want and work down to the subsonic velocity you want- at least that’s what I’ve heard but don’t take my word for it…. That was to avoid a bullet stuck in the barrel too slow…

More experienced reloaded can chime in…

 

[DieJager]

There is a similar thread from a few days old from a Russian hunter who does it successfully.

Thread '458 Lott Subsonic? It's real!'

Jun 10, 2025

Recently, I purchased HS Precision in caliber .458 Lott with 1:10 Twist for hunting bears and moose as well as for future trips to Africa. This is an excellent weapon and an excellent caliber, but I wanted to hunt with it more, as well as at night with a thermal imaging sight on deer, wild boars, wolves, beavers and other animals. The power of the cartridge is too great for these animals and,
Also, I was afraid that my sight would not withstand strong return. Then I thought about assembling cartridges with a heavy subsonic bullet that would be sufficient for these animals and would not...

• Volodia
• Replies: 19
• Forum: Firearms & ammunition

• 
• 

 

[generalzip]

Unfortunately trail boss no longer seems to exist. I have other pistol powders like h110, Hodgdon high gun (replaces titegroup I believe) and win 231. Not sure if any of these would work?

I have H4895 as well which seems to work for some in 45-70 as well as IMR 4064

 

[Riflecrank]

I have not made the plunge yet, but would want to do it with jacketed/monometal copper/brass
bullets for suppressor use.
Can't have fillers or cast bullets cluttering up a suppressor.
Until then I have collected some data from the internet for some non-suppressed subsonics.

Trail Boss with no filler and a cast 500-gr bullet with some of my scribbling added to the image:

Fortunecookie45LC Youtube screenshot with some of my typing added to it, shows a slick
subsonic 500-gr NOE with PC paint, 16.0 grains of Unique and Dacron filler,
no worries about a pressure spike from that.
Not for suppressor:

500-gr FN solids with AA-5744 might be a go, no filler.

I tried 26.0 grains of AA-5744 with a 409-gr hardcast (Berry's RNFP) and got 1182 fps and 1.2 MOA for 3 shots. 24"-barreled .458 WIN MAG.

Maybe same charge with 500-gr jacketed/monometal might slow it down to subsonic, no filler needed. Hopefully won't get stuck in barrel or suppressor.

Finally a good use for the Hornady DGS 500-gr/.458 that won't get you killed ?

Or just plink with any old RN 500-600 grainers, cast without suppressor, jacketed with suppressor.
Squash the meplat flat on a Barnes Original 600-gr RNSP, for use on pig or deer.

 

[generalzip]

I have not made the plunge yet, but would want to do it with jacketed/monometal copper/brass
bullets for suppressor use.
Can't have fillers or cast bullets cluttering up a suppressor.
Until then I have collected some data from the internet for some non-suppressed subsonics.

Trail Boss with no filler and a cast 500-gr bullet with some of my scribbling added to the image:
View attachment 692987

Fortunecookie45LC Youtube screenshot with some of my typing added to it, shows a slick
subsonic 500-gr NOE with PC paint, 16.0 grains of Unique and Dacron filler,
no worries about a pressure spike from that.
Not for suppressor:

View attachment 692988

500-gr FN solids with AA-5744 might be a go, no filler.

I tried 26.0 grains of AA-5744 with a 409-gr hardcast (Berry's RNFP) and got 1182 fps and 1.2 MOA for 3 shots. 24"-barreled .458 WIN MAG.

Maybe same charge with 500-gr jacketed/monometal might slow it down to subsonic, no filler needed. Hopefully won't get stuck in barrel or suppressor.

Finally a good use for the Hornady DGS 500-gr/.458 that won't get you killed ?

Or just plink with any old RN 500-600 grainers, cast without suppressor, jacketed with suppressor.
Squash the meplat flat on a Barnes Original 600-gr RNSP, for use on pig or deer.

Awesome info thank you! I emails Hodgdon and they said they will do a run of trail boss in the near future so I’ll hold out for that. Looks like 22 grains of trail boss with no filler and 576 grain ACME coated cast bullet would be a good place to start? You using larger or large magnum primers? I’d imagine a magnum primer couldn’t hurt things and should ensure more reliable ignition?

I’m going to aim for around 1050 fps in Texas summer weather which should get me subsonic regardless of the condition. That’s a great extreme spread you’re getting with trail boss!

 

[Sarg]

I have not made the plunge yet, but would want to do it with jacketed/monometal copper/brass
bullets for suppressor use.
Can't have fillers or cast bullets cluttering up a suppressor.
Until then I have collected some data from the internet for some non-suppressed subsonics.

Trail Boss with no filler and a cast 500-gr bullet with some of my scribbling added to the image:
View attachment 692987

Fortunecookie45LC Youtube screenshot with some of my typing added to it, shows a slick
subsonic 500-gr NOE with PC paint, 16.0 grains of Unique and Dacron filler,
no worries about a pressure spike from that.
Not for suppressor:

View attachment 692988

500-gr FN solids with AA-5744 might be a go, no filler.

I tried 26.0 grains of AA-5744 with a 409-gr hardcast (Berry's RNFP) and got 1182 fps and 1.2 MOA for 3 shots. 24"-barreled .458 WIN MAG.

Maybe same charge with 500-gr jacketed/monometal might slow it down to subsonic, no filler needed. Hopefully won't get stuck in barrel or suppressor.

Finally a good use for the Hornady DGS 500-gr/.458 that won't get you killed ?

Or just plink with any old RN 500-600 grainers, cast without suppressor, jacketed with suppressor.
Squash the meplat flat on a Barnes Original 600-gr RNSP, for use on pig or deer.

Now @Riflecrank your writing from reading the internet or guess work arent you ?

I have shot thousands of subsonic rounds, many into animals killing them, not in fairy land !

Some of these new high bullets look great (Maker - Lehigh - Peregrine & others) some even work but at quadruple the price of a nice chunk of homemade cast lead !

Never had Dacron, Backer Rod or lead problems in suppressor, saying that you must service/clean your suppressor regularly, even after each use, making sure to wipe barrel off & clean the bore, as if left on the firearm it was rust the outside & the bore, hence a lot of very short barrels here that started by people cutting back damage & then folks finding out short was better & killed as well, this is using supersonic also .

 

[Hunter4752001]

Hodgdon don't make powder, they are a distributor who re-brand propellants made by other companies. Thales (ADI) made a small batch some months ago and I scored a 2Kg tub. Since then they have made a couple of small runs of their new pistol powders as well as a tiny batch of AR2205 (IMR4227). Given the small size of these batches, I suspect they were basicaly test runs to prove the facility and processes. Hopefully larger batches won't be to far away.

 

[generalzip]

Hodgdon don't make powder, they are a distributor who re-brand propellants made by other companies. Thales (ADI) made a small batch some months ago and I scored a 2Kg tub. Since then they have made a couple of small runs of their new pistol powders as well as a tiny batch of AR2205 (IMR4227). Given the small size of these batches, I suspect they were basicaly test runs to prove the facility and processes. Hopefully larger batches won't be to far away.

They told me “near future” hopefully that means in the next few months

 

[Hunter4752001]

Correction: The Trailboss was in a 1.5Kg tub. The other pistol powders APS950 & APS650 were in 2Kg tubs.

 

[Riflecrank]

Sarg,
Excuse my ignorance.
We can't all be experts in everything.
The subsonic field is new to me, but I have cast thousands of bullets for supersonic use in rifle,
even paper-patched and with duplexed-BP in the .458 WIN MAG, works a charm.

A NOE .459"-600-grainer is ready for subsonic trial, powder-coat-painted and gas-checked,
with no filler and not to be run through my Griffin 46-Bushwacker, nope, not gonna do it.

I do see that subsonic lead would be excellent for something like this +500-pound hog I shot behind the ear at 25 yards with the CEB 400-gr Safari Solid at 2500 fps MV from a 24"-barreled .458 WIN MAG:

It is about time to try some subsonic loads for such as that,
in the .458 WIN MAG.
600-grainer for suppressor:

I been thinking about it.
Should be fun, as long as the bullet does not get stuck in the barrel.
AA-5744 ought to do it with no filler.

 

[Riflecrank]

I have 1:10" twist and 1:14" twist available in .458 WIN MAG
1:10" twist in .458 B&M,
all threaded for suppressor.

1:18" and 1:20" twist available in .45-70 Elko Magnum, no muzzle threading.

1:20" .45-70 Gov't threaded for suppressor.

One or more of those ought to gitterdun.

 

[generalzip]

I have 1:10" twist and 1:14" twist available in .458 WIN MAG
1:10" twist in .458 B&M,
all threaded for suppressor.

1:18" and 1:20" twist available in .45-70 Elko Magnum, no muzzle threading.

1:20" .45-70 Gov't threaded for suppressor.

One or more of those ought to gitterdun.

Acme said they recommended a 1-10 twist. I emailed them and showed them even subsonic a 14 twist should be ample twist to be stable. They didn’t offer much explanation other than they had better luck in 10 twist. Nevertheless I will try them out. Could have just been an accuracy issue for them. Who knows

 

[Kynoch2015]

5744 would be a great powder for this application as no filler is required. I would worry about filler getting snagged up in the baffles, building up over rounds. I know it’s obvious but work up the loads without the suppressor in place to be sure bullets aren’t keyholing. I’ve seen someone skip this step, and it didn’t work out for them. All the best.